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Unformatted text preview: Human-Computer Interaction Lecture Notes Version of 05 Apr 2011 Ao.Univ.-Prof. Dr. Keith Andrews IICM Graz University of Technology Inffeldgasse 16c A-8010 Graz kandrews@iicm.edu Copyright ©2011 Keith Andrews Contents Contents iii List of Figures viii List of Tables ix Preface xi Credits xiii 1 Human Computer Interaction 1 2 The Psychology of Usable Things 2.1 The Psychopathology of Everyday Things 2.2 The Psychology of Everyday Things . . . 2.3 The Psychopathology of Computers . . . 2.4 Interface Hall of Shame . . . . . . . . . . 2.5 User Centered Design . . . . . . . . . . . . . . . . 7 8 17 32 34 39 . . . . 41 42 44 45 49 4 Know the User 4.1 Classifying Users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Research the Frames of Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Research the End User . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 51 53 54 5 Usability Benchmarking 5.1 Competitive Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Set Usability Targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Return on Investment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 57 58 58 6 Goal-Oriented Interaction Design 6.1 Creating Personas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 Defining Goals for each Persona . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3 Defining Scenarios for each Persona . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 63 68 68 3 Usability Engineering 3.1 Defining Usability . . . . . . . . . . 3.2 Usability Evaluation . . . . . . . . 3.3 The Usability Engineering Lifecycle 3.4 Planning Usability Activities . . . . . . . . . . . . . . . . i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4 6.5 7 8 9 Moving to a Design Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Follow Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prototyping 7.1 Verbal Prototype . . . . . . . 7.2 Low-Fidelity Paper Prototypes 7.3 High-Fidelity Paper Prototypes 7.4 Interactive Sketches . . . . . . 7.5 Working Prototypes . . . . . . 7.6 Implementation . . . . . . . . Usability Inspection Methods 8.1 Heuristic Evaluation . . 8.2 Severity Ratings . . . . . 8.3 Guideline Checking . . . 8.4 Cognitive Walkthrough . 8.5 Guideline Scoring . . . . 8.6 Action Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Usability Testing Methods 9.1 Preparing for Usability Testing . 9.2 Six Stages of Conducting a Test 9.3 Thinking Aloud . . . . . . . . . 9.4 Co-Discovery . . . . . . . . . . 9.5 Formal Experiments . . . . . . . 9.6 A/B Testing . . . . . . . . . . . 9.7 Query Techniques . . . . . . . . 9.8 Usage Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Usability in Practice 10.1 Comparison of Evaluation Techniques 10.2 Discount Usability Engineering . . . . 10.3 Differences in Evaluation Practices . . 10.4 Usability Reports . . . . . . . . . . . 10.5 Usability Consulting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 71 . . . . . . 77 78 78 79 79 82 82 . . . . . . 85 86 93 94 96 100 102 . . . . . . . . 105 107 113 124 126 127 131 133 136 . . . . . 139 140 140 140 146 146 11 Visual Design and Typography 147 11.1 Typography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 11.2 Factors Influencing the Legibility of Text . . . . . . . . . . . . . . . . . . . . . . . . . 148 12 Icon Design 12.1 Visual Association . . . . . . . . . . . . 12.2 Standard Parts of an Icon . . . . . . . . . 12.3 Icon Design Principles . . . . . . . . . . 12.4 Cultural and International Issues . . . . . 12.5 Do Not Always Use Icons . . . . . . . . 12.6 Iconic Language . . . . . . . . . . . . . . 12.7 The Icon Design Lifecycle . . . . . . . . 12.8 Designing Icons for Sun’s Public Web Site ii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 156 156 157 160 162 163 166 169 13 A Brief History of HCI 173 13.1 Early Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 13.2 WIMP Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 Bibliography 188 iii iv List of Figures 1.1 The Nature of Human-Computer Interaction . . . . . . . . . . . . . . . . . . . . . . . . 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 2.18 2.19 2.20 2.21 2.22 2.23 2.24 2.25 2.26 2.27 2.28 2.29 2.30 2.31 2.32 2.33 2.34 Video Recorder . . . . . . . . . . . . . . . . . . . . Video Recorder Remote Control . . . . . . . . . . . Zeiss Slide Projector . . . . . . . . . . . . . . . . . The control panel in lecture theatre HS EDV . . . . . Audiovisual trolley with inputs at rear. . . . . . . . . Warning label on audiovisual trolley. . . . . . . . . . Where is the toilet paper? . . . . . . . . . . . . . . . Ah, there it is! . . . . . . . . . . . . . . . . . . . . . Hidden Shower Control . . . . . . . . . . . . . . . . Mop Sink . . . . . . . . . . . . . . . . . . . . . . . Mop Sink Label . . . . . . . . . . . . . . . . . . . . Car Seat . . . . . . . . . . . . . . . . . . . . . . . . Ambiguous Door Designs . . . . . . . . . . . . . . . Good Use of Affordances in Door Designs . . . . . . Example of Ambiguous Affordances in Door Design Good Use of Affordances in the Same Hotel . . . . . Seemingly Reasonable Door Affordances . . . . . . A Label as Big as the Control Panel . . . . . . . . . Arbitrary mapping of controls to hot plates . . . . . . Paired cooker controls . . . . . . . . . . . . . . . . A full, natural mapping of cooker controls . . . . . . Lego Motorbike Kit . . . . . . . . . . . . . . . . . . Assembled Lego Motorbike . . . . . . . . . . . . . . Beer Tap Handles . . . . . . . . . . . . . . . . . . . B17 Flying Fortress . . . . . . . . . . . . . . . . . . B17 Cockpit . . . . . . . . . . . . . . . . . . . . . . B17 Cockpit Control Knobs . . . . . . . . . . . . . B17F Manual . . . . . . . . . . . . . . . . . . . . . CFR 14 Control Knobs . . . . . . . . . . . . . . . . Fridge Freezer . . . . . . . . . . . . . . . . . . . . . Fridge freezer controls and instructions . . . . . . . The apparent conceptual model for the fridge freezer The actual conceptual model for the fridge freezer . . Projecting a correct conceptual model . . . . . . . . v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 9 9 10 11 12 12 14 14 15 15 16 16 18 18 18 19 19 19 21 21 21 22 22 25 26 26 27 27 28 29 29 30 30 31 2.35 2.36 2.37 2.38 2.39 2.40 2.41 2.42 2.43 2.44 2.45 2.46 Scissors project a good conceptual model . . . . . . . . . A digital watch provides no obvious conceptual model . . New Keyboard for Windows PCs . . . . . . . . . . . . . . Internet Explorer 4.0 Cache Settings Panel . . . . . . . . . Internet Explorer 4.0 Certificate Authority Selection Panel A Two-Item List Box in Visual Basic 5.0 . . . . . . . . . . A Two Thousand Item List Box . . . . . . . . . . . . . . Multi-Row Tab Controls . . . . . . . . . . . . . . . . . . Win95 Error Box . . . . . . . . . . . . . . . . . . . . . . Macintosh Trash Can . . . . . . . . . . . . . . . . . . . . Macintosh Keyboard with Eject Key . . . . . . . . . . . . Mac OS X Trash Can . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 32 35 36 36 36 37 37 38 38 38 38 3.1 3.2 3.3 3.4 Usability Engineering Cartoon . . . . . . . . . . . . . Defining Usability in Context of System Acceptability Usability Evaluation Methods by Purpose . . . . . . . The Usability Engineering Lifecycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 43 46 47 4.1 4.2 Categories of user experience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Riding the Learning Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 53 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 6.12 Elastic user . . . . . . . . . . . . . . . . . Jumble Car . . . . . . . . . . . . . . . . . Cars to Match Their Drivers . . . . . . . . The InFlight Seat Console . . . . . . . . . The InFlight Final Design . . . . . . . . . . Parallel and Iterative Design . . . . . . . . Lateral Thinking . . . . . . . . . . . . . . Survey on Menu Organisation . . . . . . . Conventional Link Style . . . . . . . . . . Non-Standard and Inconsistent Link Styles Avis Asterisk Means Optional . . . . . . . Avis Asterisk Means Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 64 64 65 69 70 71 72 73 74 74 75 7.1 7.2 7.3 7.4 7.5 7.6 7.7 Paper Prototype of IICM on Air . Working Prototype of IICM on Air Paper Prototype 1 . . . . . . . . . Paper Prototype 2 . . . . . . . . . Paper Prototype 3 . . . . . . . . . An Interactive Sketch . . . . . . . Dimensions of Prototyping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 79 80 80 81 81 83 8.1 8.2 8.3 8.4 Aggregated evaluations . . . . . . . . . . . . . . Sample Banking System Dialogue . . . . . . . . Aggregated Evaluations by Evaluator Experience The Web Usability Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 . 91 . 91 . 101 9.1 Simple Usability Test Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi . . . . . . . . . . . . . . . 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.10 9.11 9.12 9.13 9.14 9.15 9.16 9.17 Single Room, Single Camera Test Setup . . . . . . . . Example Single Room, Single Camera Test . . . . . . Alternative Single Room Setup . . . . . . . . . . . . . Observation Room with Electronic Monitoring . . . . Classical Usability lab . . . . . . . . . . . . . . . . . Microsoft Usability lab . . . . . . . . . . . . . . . . . Morae Test Setup . . . . . . . . . . . . . . . . . . . . Portable Usability Kit . . . . . . . . . . . . . . . . . . Portable Usability Kit 2 . . . . . . . . . . . . . . . . . Example Internal Task List . . . . . . . . . . . . . . . Orientation script for Harmony usability test . . . . . . Background Questionnaire for Harmony Usability Test Combined nondisclosure and consent form . . . . . . . A Generic Data Collection Form . . . . . . . . . . . . Completed Data Collection Form . . . . . . . . . . . . Example Test Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 108 109 109 110 110 111 112 112 115 116 117 118 119 119 121 10.1 Hotmail password hint question . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 10.2 Hotmail redesigned secret question . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 10.3 Hotmail compose new message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 11.1 Serif and Sans Serif Fonts . . . . . . . . . . . . . . . . 11.2 Proportional Versus Fixed Width Fonts . . . . . . . . . 11.3 Font Size Changes . . . . . . . . . . . . . . . . . . . 11.4 All Upper Case Slows Reading . . . . . . . . . . . . . 11.5 Lower and Mixed Case Words Have Distinctive Shapes 11.6 En and Em Word Spacing . . . . . . . . . . . . . . . . 11.7 Line Spacing . . . . . . . . . . . . . . . . . . . . . . 11.8 Characters per Line . . . . . . . . . . . . . . . . . . . 11.9 Flush and Justified Text Styles . . . . . . . . . . . . . 11.10Using a Layout Grid . . . . . . . . . . . . . . . . . . 11.11Text Right Up To Margins . . . . . . . . . . . . . . . 11.12Text with Ample Margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 149 149 150 150 150 150 151 152 153 154 154 12.1 The Standard Parts of an Icon . . . . . . . . 12.2 Visually Imbalanced Icons . . . . . . . . . 12.3 Mixed Levels of Realism in Icons . . . . . 12.4 Symbols for Men and Women . . . . . . . 12.5 Typical Viewing Distances to Icons . . . . . 12.6 Symbol silhouette conveys most information 12.7 Garish Multicolour Icons . . . . . . . . . . 12.8 Well-Balanced, Consistent Icons . . . . . . 12.9 Evolution of Microsoft Word icon bar . . . 12.10Language-Dependent Text in Icons . . . . . 12.11Culturally-Dependent Mailbox Icons . . . . 12.12Icons for Food and Drink areas . . . . . . . 12.13Words for Food and drink Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 157 158 159 159 159 160 161 161 161 161 162 162 vii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.14The Icon Design Lifecycle . . . . . . . . . 12.15Test Setup for Icon Intuitiveness Test . . . . 12.16An Icon Intuitiveness Test in Progress . . . 12.17Room Setup for Icon Test . . . . . . . . . . 12.18Icon Iterations for “Products and Solutions” 12.19Icon Iterations for “Sun on the Net” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 167 168 168 169 171 13.1 13.2 13.3 13.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 175 176 177 Memex Overview . . . . . . . . . Memex Detail View . . . . . . . . SketchPad . . . . . . . . . . . . . Augment/NLS Production Mouse . . . . . . . . . . . . . . . . . . . . viii List of Tables 5.1 Survey of usability budgets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 6.1 6.2 6.3 6.4 6.5 Differences Between Computers and Humans Programmers Think and Behave Differently . Personal and Corporate Goals are Different . Four Main Passenger Personas . . . . . . . . Five Main Employee Personas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 61 62 66 67 8.1 8.2 8.3 8.4 8.5 Heuristic Evaluation Number of Problems Found . . Heuristic Evaluation Aggregating Individual Results Proportion of Evaluators by Experience . . . . . . . One of the 944 guidelines by Smith and Mosier. . . Average Times for Typical Keystroke-Level Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 . 89 . 92 . 94 . 102 9.1 Simple Coding Scheme for Event Logging . . . . . . . . . . . . . . . . . . . . . . . . . 119 12.1 12.2 12.3 12.4 12.5 Iconic language for Windows NT 4.0 documents . . . . . . . . . Iconic language for document and link icons in Harmony . . . . . First Round of Icon Designs for “Technology and Developers” . . Second Round of Icon Designs for “Technology and Developers” . Third Round of Icon Designs for “Technology and Developers” . . ix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 165 170 170 170 x Preface I first started teaching human-computer interaction at Graz University of Technology in 1993. These lecture notes have evolved since then, and have benefitted from my teaching courses on user interface design at FH Technikum K¨ rnten in Villach, web usability and advanced user interfaces at FH Joanneum a in Graz, human-computer interaction at FH Hagenberg near Linz and numerous intensive courses at conferences and for industry. I would like to thank my many tutors for their many helpful ideas and comments over the years. I would also like to thank all my students past and present for their many suggestions and corrections which have helped to massage these notes into their current form. Printing this Document You may sometimes experience difficulties printing the entire document at once. Depending on the amount of memory in your printer, a single printed page containing one or more high resolution images or complicated diagrams might cause the printer to run out of RAM while assembling the page. If this happens, try printing the document a chunk at a time and printing complicated pages individually. References in Association with Amazon References with an ISBN number are linked to amazon.com (or amazon.co.uk or amazon.de) for easy lookup and possible purchase. Amazon pay me a small referral fee for each item you purchase after following such a link – the item itself does not cost you any more. If you find these notes useful and would like to contribute towards their maintenance, please purchase any book you might want after following a specific ISBN link from here. Thanks and happy reading, Keith xi xii Credits • The photographs in Figures 2.9, 2.10, 2.11, and 2.12 are used courtesy of Baddesigns.Com (Michael J. Darnell) [Darnell, 2010]. • The photograph in Figure 2.18 is used with kind permission of Karl Voit. • The material in Section 2.4 is from the Interface Hall of Shame and is used with kind permission from Brian Hayes, Isys Information Architects Inc. • The screenshot in Figure 6.11 is used with kind permission of Jared Spool [Spool, 2005]. • The paper prototype images of the Northumberland Bank interface in Section 3.3 are used with kind permission from Cliff Brown, University of Northumbria at Newcastle. • The material in Section 10.3 on Comparative Usability Evaluation is used with kind permission from Rolf Molich, DialogDesign, Denmark. • The material in Section 12.8 on Icon Design is used with kind permission from Jakob Nielsen. • Figures 13.1 and 13.2 are screen shots from the Memex animation [Adelman and Kahn, 1995], and are used with kind permission of Paul Kahn. • Figure 13.4 is used with kind permission of Stanford University, Special Collections. The following figures are used under the terms of the Sun Microsystems Copyright Notice (see page xiii): • The photograph of Ivan Sutherland’s SketchPad system used in Figure 13.3, taken from the sun. com web site (it is no longer there). Sun Microsystems Copyright Notice Copyright 1996 Sun Microsystems, Inc. 2550 Garcia Avenue, Mountain View, California 94043-1100 U.S.A. All rights reserved. Copyright in this document is owned by Sun Microsystems, Inc. Any person is hereby authorized to view, copy, print, and distribute this document subject to the following conditions: 1. The document may be used for informational purposes only. 2. The document may only be used for non-commercial purposes. 3. Any copy of this document or portion thereof must include this copyright notice. xiii xiv Chapter 1 Human Computer Interaction “ Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them. ” [ ACM SIGCHI Curricula for Human-Computer Interaction ] References ++ Cooper, Reimann, and Cronin; About Face 3: The Essentials of Interaction Design; Wiley, 2007. ISBN 0470084111 (com, uk) [Cooper et al., 2007] + Alan Cooper; The Inmates are Running the Asylum; Sams, 2004. ISBN 0672326140 (com, uk) [Cooper, 2004] ++ Steve Krug; Rocket Surgery Made Easy; New Riders, 2009. ISBN 0321657292 (com, uk) ++ Steve Krug; Don’t Make Me Think!: A Common Sense Approach to Web Usability; 2nd Edition, New Riders, 2005. ISBN 0321344758 (com, uk) + Lazar, Feng, and Hochheiser; Research Methods in Human-Computer Interaction; Wiley, 2010. ISBN 0470723378 (com, uk) [Lazar et al., 2010] + Kim Goodwin and Alan Cooper; Designing for the Digital Age: How to Create Human-Centered Products and Services; Wiley, February 2009. ISBN 0470229101 (com, uk) [Goodwin and Cooper, 2009] + Stone, Jarrett, Woodruffe, and Minocha; User Interface Design and Evaluation; Morgan Kaufmann, March 2005. ISBN 0120884364 (com, uk) [Stone et al., 2005] + Isaacs and Walendowski; Designing from Both Sides of the Screen; Sams, 2001. ISBN 0672321513 (com, uk) [Isaacs and Walendowski, 2001] • Jef Raskin; The Humane Interface; Addison-Wesley, March 2000. ISBN 0201379376 (com, uk) [Raskin, 2000] • Ben Shneiderman and Catherine Plaisant; Designing the User Interface; 5th Edition, AddisonWesley, March 2009. ISBN 0321537351 (com, uk) [Shneiderman and Plaisant, 2009] • Sharp, Rogers, and Preece; Interaction Design; 2nd Edition, Wiley, 2007. ISBN 0470018666 (com, uk) 1 2 CHAPTER 1. HUMAN COMPUTER INTERACTION Use and Context Application Areas and Tasks Human Social Organisation Human-Machine Fit Computer Human Human Information Processing Dialogue Techniques Interface Metaphors Language, Communication I/O Devices Ergonomics A Graphic Design Prototypes Evaluation Techniques Implementation Techniques and Tools Design Approaches Development Process Figure 1.1: The nature of Human-Computer Interaction. Adapted from Figure 1 of the ACM SIGCHI Curricula for Human-Computer Interaction [Hewett et al., 2002] 3 • Jenny Preece et al; Human-Computer Interaction; Addison-Wesley, 1994. ISBN 0201627698 (com, uk) [Preece et al., 1994] • Terry Winograd (Ed.); Bringing Design to Software; Addison-Wesley, April 1996. ISBN 0201854910 (com, uk) • Helander, Landauer, Prabhu (Eds.); Handbook of Human-Computer Interaction; 2nd Edition, Elsevier, 1997. 1602 pages. ISBN 0444818626 (com, uk) [Helander et al., 1997] • Jacko and Sears (Eds.); The Human-Computer Interaction Handbook; Lawrence Erlbaum, Sep. 2002. 1277 pages. ISBN 0805844686 (com, uk) [Jacko and Sears, 2002] • Bruce Tognazzini; Tog on Interface; Addison-Wesley, 1992. ISBN 0201608421 (com, uk) [Tognazzini, 1992] • Bruce Tognazzini; Tog on Software Design; Addison-Wesley, 1995. ISBN 0201489171 (com, uk) [Tognazzini, 1995] • Baecker et al; Human-Computer Interaction: Toward the Year 2000; Morgan Kaufmann, 1995. ISBN 1558602461 (com, uk) [Baecker et al., 1995] • Baecker and Buxton; Readings in Human-Computer Interaction; Morgan Kaufmann, 1987. ISBN 0934613249 (com, uk) [Baecker and Buxton, 1987] • John Anderson; Cognitive Psychology and its Implications; 6th Edition, Worth, 2004. ISBN 0716701103 (com, uk) [Anderson, 2004] • Robert Bailey; Human Performance Engineering; 3rd Edition, Pearson Education, Jan. 1996. ISBN 0131496344 (com, uk) [Bailey, 1996] • Wickens et al; An Introduction to Human Factors Engineering; 2nd Edition, Prentice Hall, 2003. ISBN 0131837362 (com, uk) [Wickens et al., 2003] • William Calvin; How Brains Think; Basic Books, 1997. ISBN 046507278X (com, uk) [Think, 1997] References in German + Steve Krug; Web Usability: Rocket Surgery Made Easy; Addison-Wesley, 2010. ISBN 3827329744 (com, uk) + Steve Krug; Don’t make me think!: Web Usability: Das intuitive Web; 2. Auflage, mitp Verlag, 2006. ISBN 3826615956 (com, uk) + Martina Manhartsberger und Sabine Musil; Web Usability - Das Prinzip des Vertrauens; Galileo Press, 2001. ISBN 3898421872 (com, uk) • Florian Sarodnick and Henning Brau; Methoden der Usability Evaluation; Huber, 2006. ISBN 3456842007 (com, uk) Standards • ISO 9241 Ergonomics requirements for office work with visual display terminals (VDTs), 1998. http://www.iso.org/ • ISO 13407 Human-centred design processes for interactive systems, 1999. http://www.iso.org/ 4 CHAPTER 1. HUMAN COMPUTER INTERACTION Online Resources • Wikipedia; Human-Computer Interaction; http://en.wikipedia.org/wiki/Human-computer_ interaction • ACM SIGCHI http://acm.org/sigchi/ • Usability Professionals’ Association http://www.upassoc.org/ • Society for Technical Communication (STC); Topics in Usability; http://www.stcsig.org/usability/topics/index.html • Usability Body of Knowledge http://www.usabilitybok.org/ • UXmatters; http://www.uxmatters.com/ • HCI Index; http://degraaff.org/hci/ • Human-Computer Interaction Resources Network (HCI RN) http://www.hcirn.com/ • HCI Bibliography http://www.hcibib.org/ • Newsgroup news:comp.human-factors • ACM Digital Library http://www.acm.org/dl [For students $ 42.00 per year http://www.acm.org/membership/student/] [Free access from IP addresses within TU Graz through ACM http://acm.org/dl/] • IEEE Computer Society Digital Library http://www.computer.org/publications/dlib/ [For students $ 99.00 per year. http://www.computer.org/join/] [Free access from IP addresses within TU Graz through IEEE Explore http://ieeexplore.ieee.org/] Journals • interactions; ACM; ISSN 1072-5520 http://www.acm.org/interactions/ • Transactions on Computer-Human Interaction (TOCHI); ACM; ISSN 1073-0516 http://www. acm.org/tochi/ • International Journal of Human-Computer Interaction (IJHCI); Lawrence Erlbaum; ISSN 10447318 http://www.leaonline.com/loi/ijhc • International Journal of Human-Computer Studies (IJHCS); Elsevier; ISSN 1071-5819 http:// www.sciencedirect.com/science/journal/10715819 • Behaviour & Information Technology (BIT); Taylor & Francis; ISSN 0144-929X http://www. tandf.co.uk/journals/tf/0144929X.html • Journal of Usability Studies (JUS); Usability Professionals’ Association ISSN 1931-3357 http: //www.upassoc.org/upa_publications/jus/ 5 Conferences • Conferences sponsored by or in cooperation with ACM SIGCHI http://sigchi.org/ conferences/ • CHI; Annual SIGCHI Conference: Human Factors in Computing Systems; http://chi2011.org/ • AVI; Advanced Visual Interfaces; http://www.dis.uniroma1.it/avi2010/ • UPA; Usability Professionals’ Association; http://www.upassoc.org/conferences_and_ events/ • HCII; Human-Computer Interaction International http://www.hci-international.org/ • Usab; Symposium of the HCI&UE Working Group of the Austrian Computer Society; http:// usab2010.uni-klu.ac.at/ The Front Desk • The Front Desk Bruce Tognazzini and the BBC [BBC, 1996], 30 minute video. 6 CHAPTER 1. HUMAN COMPUTER INTERACTION Chapter 2 The Psychology of Usable Things “ When simple things need pictures, labels, or instructions, the design has failed. ” [ Don Norman, The Design of Everday Things, 1988 [Norman, 1992, page 9] ] References ++ Donald Norman; The Design of Everyday Things; Basic Books, 1992. ISBN 0465067107 (com, uk) [Norman, 1992] [ This is a paperback reprint of the original hardbound book The Psychology of Everyday Things [Norman, 1988]. ] • Donald Norman; Turn Signals Are the Facial Expressions of Automobiles; Addison-Wesley, 1993. ISBN 020162236X (com, uk) [Norman, 1993] • Donald Norman; Things That Make Us Smart; Addison-Wesley, 1994. ISBN 0201626950 (com, uk) [Norman, 1994] • Lakoff and Johnson; Metaphors We Live By; Second Edition, University of Chicago Press, 1980. ISBN 0226468011 (com, uk) [Lakoff and Johnson, 1980] • Leonard Lee; The Day the Phones Stopped Ringing; Plume, 1992. ISBN 1556112866 (com, uk) [Lee, 1992] [Out of print] • Jeff Johnson; GUI Bloopers 2.0; Morgan Kaufman, 2007. ISBN 0123706432 (com, uk) [Johnson, 2007] • Jeff Johnson; Web Bloopers; Morgan Kaufman, 2003. ISBN 1558608400 (com, uk) [Johnson, 2003] • Vincent Flanders and Michael Willis; Web Pages That Suck; Sybex, 1998. ISBN 078212187X (com, uk) [Flanders and Willis, 1998] • Vincent Flanders and Dean Peters; Son of Web Pages That Suck; Sybex, 2002. ISBN 0782140203 (com, uk) [Flanders and Peters, 2002] Online Resources • Michael Darnell; Bad Human Factors Designs; http://baddesigns.com/ [Darnell, 2010] • Mark Hurst; This Is Broken; http://thisisbroken.com/ 7 8 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS • Wired; History’s Worst Software Bugs; http://www.wired.com/software/coolapps/news/ 2005/11/69355 • Computer Stupidities; http://www.rinkworks.com/stupid/ • Web Pages That Suck; http://webpagesthatsuck.com/ • Wikipedia; Affordance; http://en.wikipedia.org/wiki/Affordance • Wikipedia; Natural Mapping; http://en.wikipedia.org/wiki/Natural_mapping 2.1 The Psychopathology of Everyday Things Examples of where the design of everyday things went wrong. Opening a Milk Carton • Classic example from Austrian TV [ORF, 1987]. • Glass bottles were being replaced by new cartons. • On live TV, a manager demonstrates how easy it is to open the new cartons. . . • . . . but everything goes rather wrong! • The original was broadcast live on the program “wir”, but was later rebroadcast in the outtake show “Hoppala” (hence the laughter over the original soundtrack). Early Tractors • Early tractors had a high centre of gravity and narrow wheel base. • On rough, hilly surface → disaster! • Used to be called “driver error”. • More probably “design error”, since tractors today are designed with a low centre of gravity and wide wheel base. The Frustrations of Everyday Life Can you use all the functions of your: • digital watch? • mobile phone? • washing machine? • video recorder? 2.1. THE PSYCHOPATHOLOGY OF EVERYDAY THINGS Figure 2.1: The most basic functionality of a video recorder, playing a tape, is easy to use. However, anything more advanced, such as programming a recording, can become rather difficult. Figure 2.2: Some of the buttons on a VCR remote control are easy to understand, but others are unfathomable without the instruction manual. 9 10 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Figure 2.3: The Zeiss Ikon Perkeo 511 slide projector. A short press advances to the next slide, a long press moves back one slide, but how should first-time users know this? [Thanks to Horst Ortmann for providing the photograph.] Zeiss Slide Projector • Only one button to control the slide advance, see Figure 2.3. • During lectures, sometimes the slides go forwards, sometimes they go backwards . . . • If you can find an instruction manual: Short press = forward, long press = backward. • What an elegant design, two functions with just one button! • But how should first-time users know what to do? The Louis-Laird Amphitheatre in the Sorbonne • Magnificent murals on the ceiling. – But only the right way up for the lecturer. • Electric projection screen. – Has to be lowered from a back room up a short flight of stairs, out of sight. Could Someone Please Turn the Lights Down • Figure 2.4 shows the control panel for the lecturer at the front of the old lecture theatre HS EDV. 2.1. THE PSYCHOPATHOLOGY OF EVERYDAY THINGS 11 Start Deckenlicht Tafellicht 0 1 DIA Projektor 0 1 2 Lüftung Figure 2.4: The control panel for the lecturer in the old lecture theatre HS EDV of Graz University of Technology. • I often had to assist guest speakers in turning the lights down (but not completely off). • The problem is that four (!) separate controls are mapped to the single green button (Deckenlicht): – Depressing and releasing the green button either turns the lights completely on or completely off, depending on whether they are currently on or off. – Holding the green button down either dims or increases lighting, depending on whether it was last dimmed or increased. • The air conditioning control (L¨ ftung) is also problematic: 0 is off, 1 is on, and 2 is off (!). u Clunky Connector • The audiovisual control trolley (see Figure 2.5) at the front of lecture theatre HS EDV also caused me a major problem. • Intending to hook up my laptop to the ceiling mounted projector, I unwittingly unscrewed the monitor cable connector from the outside of the trolley. • This resulted in a dull clunking sound from inside the trolley. • Unfortunately, the internal connector had only been secured by virtue of its being attached to the external connector! • It took three days for a technician to arrive, disassemble the trolley, and reconnect everything. • To remind myself and to warn others, I resorted to the last ditch technique of providing the label shown in Figure 2.6. 12 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Figure 2.5: The audiovisual trolley in lecture theatre HS EDV has input connectors at the rear. Unfortunately, unscrewing the external connector causes the internal connector to fall with a clunk somewhere inside the trolley! Figure 2.6: I provided this label as a warning to myself and others. 2.1. THE PSYCHOPATHOLOGY OF EVERYDAY THINGS 13 Where is the Toilet Paper? • Fancy hotel, nice bathrooms, see Figure 2.7. • Having sat down and done the business, where the heck is the toilet paper? • Ah, there it is! Well-hidden, see Figure 2.8. Shower Control • Shower control: water either goes into the bath out of the faucet or comes out of the shower. See Figure 2.9. • Sticker with instructions on the faucet. • How do you make the water come out of the shower instead of the faucet? • You have to reach under the faucet and pull the knob down! • This example is from Baddesigns.Com [Darnell, 2010] http://baddesigns.com/shower1.html This is a Mop Sink • A picture from the men’s toilet of a restaurant in Santa Barbara, see Figure 2.10. • There is no urinal in the toilet. • Where do you think most men relieve themselves? • The label says “This is a Mop Sink”, see Figure 2.11. • The mop sink looks enough like a urinal to be used as one. • This example is from Baddesigns.Com [Darnell, 2010] http://baddesigns.com/mopsnk.html Car Seat • A seat in a mini-van (people carrier), see Figure 2.12. • What do you think happens when you pull the lever under the seat? • Most normal-thinking people would expect the seat to slide backward or forward. • Not in this mini-van. Pulling the lever detaches the seat from the floor to make room for cargo! • This example is from Baddesigns.Com [Darnell, 2010] http://baddesigns.com/carseat.html 14 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Figure 2.7: Can you see where the toilet paper is in this hotel bathroom? Figure 2.8: The toilet paper is well-hidden under the ledge, and is impossible to find without the sign. 2.1. THE PSYCHOPATHOLOGY OF EVERYDAY THINGS Figure 2.9: Hidden shower control. To divert water to the shower, you have to pull down on the knob beneath the faucet. [Photograph courtesy of Baddesigns.Com [Darnell, 2010].] Figure 2.10: The men’s toilet in a restaurant in Santa Barbara. The fixture in the corner affords a certain activity. It is, however, not a urinal but a mop sink. [Photograph courtesy of Baddesigns.Com [Darnell, 2010].] 15 16 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Figure 2.11: A close-up of the label. It reads “This is a Mop Sink”. [Photograph courtesy of Baddesigns.Com [Darnell, 2010].] Figure 2.12: The lever beneath this mini-van seat does not work as expected. Instead of allowing the seat to slide backward or forward, pulling the lever detaches the seat from the floor to make room for cargo! [Photograph courtesy of Baddesigns.Com [Darnell, 2010].] 2.2. THE PSYCHOLOGY OF EVERYDAY THINGS 2.2 17 The Psychology of Everyday Things Perceived and Real Affordances Affordances are the range of possible (physical) actions by a user on an artefact: • Perceived Affordances are the actions a user perceives to be possible. • Real Affordances are the actions which are actually possible. See [Norman, 1999] for a discussion of affordances and perceived affordances. Real World Affordances For physical objects, there can be both real and perceived affordances (and the two sets are not necessarily the same). • Appearance indicates how to use something: – A chair affords (suggests) sitting. – Knobs are for turning. – Slots are for inserting things. – A button affords pushing. • When perceived affordances are taken advantage of, the user knows what to do just by looking. Figures 2.13 and 2.14 illustrate the perceived affordances of door handles. Labels • “When simple things need pictures, labels, or instructions, the design has failed!” Norman [1992, page 9] • See Figure 2.18. GUI Affordances For screen-based interfaces, the computer hardware already has built-in physical affordances: • Screen affords touching. • Mouse affords pointing. • Mouse buttons afford clicking. • Keyboard affords typing. Changing the shape of the cursor to indicate a clickable link is not an affordance (you can still click anywhere), but visual feedback. Physically locking the mouse button on non-clickable areas is a real affordance. 18 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Figure 2.13: Ambiguous door designs. A knob affords turning, but do you push or pull? A horizontal bar affords pushing, but which side do you push on? Figure 2.14: Good use of affordances in door designs. A flat panel affords pushing and the broadness indicates which side to push. A vertical handle affords grasping and pulling. Figure 2.15: An example of ambiguous affordances in door design. The vertical handles mounted on both sides of the door suggest grasping and pulling. Unfortunately, from one side, the door has to be pushed! Note the signs above the handles. 2.2. THE PSYCHOLOGY OF EVERYDAY THINGS Figure 2.16: Good use of affordances in the same hotel. This door is well designed. The vertical handle correctly suggests pulling, the flat bar correctly suggests pushing. Figure 2.17: The affordances for this door seem reasonable within themselves. Context is everything. Hopefully, the door is kept locked! Figure 2.18: A label as big as the control panel. [Photograph taken at TU Chemnitz, Germany in March 2008. Used with kind permission of Karl Voit.] 19 20 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Mappings Mappings are the relationships between controls and their effects on a system. Natural mappings take advantage of physical analogies and cultural standards. Examples: • Turn steering wheel clockwise to turn a car right. Actually, there are two mappings here: – which control affects steering, – which direction to turn it. • Move a control up to move an object up. • Use a louder sound to mean a greater amount. Mapping of Cooker Controls How should one arrange the hot plate controls on a cooker? • Arbitrary Mapping (see Figure 2.19). • Paired Mapping (see Figure 2.20). • Full Natural Mapping (see Figure 2.21). Adapted from Norman, The Design of Everyday Things, Figures 3.3, 3.4, and 3.5 [Norman, 1988]. Constraints The difficulty of dealing with a novel situation is directly related to the number of possibilities. Constraints are physical, semantic, cultural, and logical limits on the number of possibilities. • Physical constraints such as pegs and holes limit possible operations. • Semantic constraints rely upon our knowledge of the situation and of the world. • Cultural constraints rely upon accepted cultural conventions. • Logical constraints exploit logical relationships. For example a natural mapping between the spatial layout of components and their controls. Where affordances suggest the range of possibilities, constraints limit the number of alternatives. Constraints in Lego Motorbike Motorbike toy with 12 parts. Constraints make its construction simple, even for adults! • Physical: Front wheel only fits in one place. • Semantic: The rider sits on the seat facing forward. • Cultural: Red is a rear light, yellow a front light. • Logical: Two blue lights, two white pieces, probably go together. See Figures 2.22 and 2.23. 2.2. THE PSYCHOLOGY OF EVERYDAY THINGS back right back left front right 21 front left Figure 2.19: Arbitrary mapping of controls to hot plates. There are 24 possible arrangements, requiring the use of labels and memory. back front front back Figure 2.20: Paired cooker controls. Now there are only four possible arrangements, two on each side, but confusion can still occur. Figure 2.21: A full, natural mapping of cooker controls. There is no ambiguity, no need for learning or remembering, and no need for labels. 22 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Figure 2.22: The design takes advantage of constraints to make its construction simple. Figure 2.23: The assembled lego motorbike. 2.2. THE PSYCHOLOGY OF EVERYDAY THINGS 23 Conventions Conventions are cultural constraints. They are initially arbitrary, but evolve and become accepted over time. They can however still vary enormously across different cultures, for example: • Light switches: America down is off Britain down is on • Water taps: America anti-clockwise is on Britain anti-clockwise is off • The colour red: America danger Egypt death India life China happiness The Principle of Causality Causality is when something which happens right after an action, appears to have been caused by that action. There are two kinds of false causality: • Coincidental effects lead to superstition: – Touch a computer terminal just before it fails, and you are apt to believe you caused the failure. – Start an unfamiliar application, just before the computer crashes. • Invisible effects lead to confusion: – When an action has no apparent result, you may conclude it was ineffective (and repeat it). – For example, repeatedly clicking the “Stop” button when the system is unresponsive. → There is a need for feedback! The Structure of Human Memory Short-Term Memory (STM) Short-term memory is the memory of the present, used as working or temporary memory. • Information is retained in STM automatically and is retrieved without effort. • However, the amount of information in STM is severely limited: 7 ± 2 items [Miller, 1956] • STM is extremely fragile – the slightest distraction and its contents are gone. For example, STM can hold a seven digit phone number from the time you look it up until the time you use it, as long as no distractions occur. 24 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Long Term Memory (LTM) Long-term memory is the memory of the past. • It takes time to put stuff into LTM and time and effort to get stuff out. • Capacity is estimated at about 100 million items. Knowledge in the Head and in the World Not all of the knowledge required for precise behaviour has to be in the head. It can be distributed: • partly in the head • partly in the world • and partly in the constraints of the world. Placing Knowledge in the World Having knowledge in the world reduces the load on human memory: • An example of the input format can be provided in the interface: Please enter the date (yyyy/mm/dd): • Previously entered values can be used as defaults, so users do not have to remember items between screens. • Control-room operators at a nuclear power plant fixed beer-tap handles to similar-looking knobs, so as to better distinguish between them. See Figure 2.24. However, allow expert users to internalise knowledge for faster and more efficient performance. Shape Coding for Aircraft Control Knobs • During the first years of World War 2, there were dozens of gear-up accidents when landing B-17, B-25, and P-47 aircraft [Koonce, 2002, page 95]. • Pilots frequently retracted the landing gear instead of the flaps after landing. See Figure 2.25. • In 1943, Lt. Alphonse Chapanis was ordered to investigate and noticed that C-47 transport (DC3 Dakota) pilots suffered no such accidents [Roscoe, 1997, page 3]. • In the B-17, the control knobs for flaps and landing gear were identical and located close to one another, as shown in Figures 2.26, 2.27, and 2.28. • In the C-47, the flaps control was totally separate and was activated like a modern car handbrake. • Chapanis realised that so-called “pilot errors” were really “designer errors” [Chapanis, 1999, page 16]. • As a quick fix, a small rubber wheel was attached to the end of the landing gear control and a wegde shape to the flap control. 2.2. THE PSYCHOLOGY OF EVERYDAY THINGS 25 Figure 2.24: Beer tap handles mounted atop similar-looking knobs in the control room of a nuclear power plant to help operators distinguish between them. [Original photograph by Joseph L. Seminara, scanned from Norman [1988, page 95] with permission from Don Norman.] • The gear-up landings ceased. • After the war, the shape-coded wheel and flap controls were standardised and are still used today [CFR, 2008, pages 253–254], as shown in Figure 2.29. To Err is Human • People make errors routinely, you must design for error. • Assume that any error, that can be made, will be made! • Design explorable systems, where operations are easy to reverse. Categories of Error Two fundamental categories of error: • Slips result from automatic behaviour, when subconscious actions toward a correct goal go wrong. • Mistakes result from conscious deliberations, which formed an inappropriate goal. Conceptual Models A conceptual model is a mental model of how something works, which is formed inside a person’s head. A user’s conceptual model built up and influenced by numerous factors, including: • familiarity with similar devices (transfer of previous experience) • affordances • mapping 26 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Figure 2.25: The B17 Flying Fortress. [From Emgonzalez [2005], the image was placed in the public domain by the photographer.] Figure 2.26: The cockpit of a B17G Flying Fortress. The landing gear and flaps control knobs are identical and are very close to one another. [From USAF [2006], image believed to be in the public domain.] 2.2. THE PSYCHOLOGY OF EVERYDAY THINGS Figure 2.27: Close-up of the cockpit control knobs of a B17G Flying Fortress. The landing gear and flaps control knobs are identical and are very close to one another. [From USAF [2006], image believed to be in the public domain.] Figure 2.28: Page 53 from the B-17F Airplane Pilot’s Flight Operating Instructions. Item 8 is the landing gear control switch and item 10 is the flap control. [From USAF [1942].] 27 28 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Figure 2.29: After WW2, the shape coding for landing gear and flaps control knobs was standardised. The landing gear control resembles a wheel and the flaps control resembles a flap. [From CFR [2008, page 254].] • constraints • causality • instructions • interacting with the device. Conceptual models may be wrong, particularly if the above factors are misleading. A Conceptual Model of a Fridge Freezer A fridge-freezer with two compartments: the fridge for fresh food at the bottom and the freezer for frozen goods at the top, as shown in Figure 2.30: • The two control dials (Figure 2.31) suggest a particular conceptual model (Figure 2.32) for operating the fridge freezer. • Unfortunately, the apparent conceptual model does not match the way the fridge freezer actually works (Figure 2.33). Adapted from [Norman, 1988], pages 17–18. Projecting a Correct Conceptual Model • Designers have their own conceptual model of a system, the design model. 2.2. THE PSYCHOLOGY OF EVERYDAY THINGS 29 Freezer NORMAL SETTINGS C 5 1 SET BOTH CONTROLS COLDER FRESH FOOD B C D E 7 6 5 4 C AND 6-7 2 B AND AND 8-9 ALLOW 24 HOURS TO STABILIZE COLDEST FRESH FOOD COLDER FREEZER 3 D AND 7-8 WARMER FRESH FOOD A C AND 4-1 OFF (FRESH FD & FRZ) 0 Fresh Food Figure 2.30: The fridge freezer. NORMAL SETTINGS C AND 5 1 SET BOTH CONTROLS COLDER FRESH FOOD C AND 6-7 2 COLDEST FRESH FOOD B AND 8-9 ALLOW 24 HOURS TO STABILIZE COLDER FREEZER D AND 7-8 WARMER FRESH FOOD C AND 4-1 OFF (FRESH FD & FRZ) A B C FREEZER 0 D E 7 6 5 FRESH FOOD Figure 2.31: The fridge freezer controls and instructions. 4 3 30 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Thermostat Freezer Control Freezer Cold Air Cooling Unit Thermostat Fresh Food Control Cold Air Cooling Unit Fresh Food Figure 2.32: The apparent conceptual model for the fridge freezer, gleaned from the controls and instructions, is that each control is responsible for the temperature of the corresponding compartment. Thermostat (location unknown) Control A Freezer Valve Cold Air Cooling Unit Control B Fresh Food Figure 2.33: The actual conceptual model for the fridge freezer. In fact, there is only one thermostat and only one cooling unit. One control adjusts the thermostat setting, the other controls the relative proportion of cold air! 2.2. THE PSYCHOLOGY OF EVERYDAY THINGS 31 User's Model Design Model User Designer System System Image Figure 2.34: Projecting a correct conceptual model. Designers should take care to project an accurate conceptual model through the system image. Figure 2.35: Scissors project a good conceptual model. • The system image is the actual implementation or embodiment of the design (including documentation, instructions, and labels). • The user’s model is built through interaction with the system. The designer expects the user’s model to be the same as the design model, however all communication takes place through the system image. → The system image should make the design model clear and consistent. A Pair of Scissors Projects a Good Conceptual Model • Affordances: holes for putting fingers in. • Constraints: small hole for thumb, big hole for several fingers. • Mapping: between holes and fingers suggested and constrained by appearance. • Conceptual Model: operating parts are visible and their implications are clear. 32 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS 13:16 Figure 2.36: A digital watch provides no obvious conceptual model. A Digital Watch Projects No Visible Conceptual Model • Affordances: four buttons to push – but what do they do? • Mapping: no clear relationship between buttons and possible actions. • Transfer of Prior Knowledge: little similarity to analog watches. • Conceptual Model: must be learnt from instructions. 2.3 The Psychopathology of Computers Usability “war stories” concerning computers . . . The PC Cup Holder A supposedly true story from a Novell NetWire SysOp: Caller: Tech Rep: Caller: Tech Rep: Caller: Tech Rep: Caller: “Hello, is this Tech Support?” “Yes, it is. How may I help you?” “The cup holder on my PC is broken and I am within my warranty period. How do I go about getting that fixed?” “I’m sorry, but did you say a cup holder?” “Yes, it’s attached to the front of my computer.” “Please excuse me if I seem a bit stumped, it’s because I am. Did you receive this as part of a promotional, at a trade show? How did you get this cup holder? Does it have any trademark on it?” “It came with my computer, I don’t know anything about a promotional. It just has ’4X’ on it.” At this point the Tech Rep had to mute the caller, because he couldn’t stand it. The caller had been using the load drawer of the CD-ROM drive as a cup holder, and snapped it off the drive. This story was found at Greenberg [1997] and is attributed there to George Wagner g.wagner@sylvania.sev.org. 2.3. THE PSYCHOPATHOLOGY OF COMPUTERS 33 Dangerous Command Names A widely used text editor (ed) used the character ’.’ to select the current line of text, and ’,’ to select the entire document for an operation. • These two keys are adjacent on the keyboard → highly likely they will sometimes be mistaken. • Intending to change one line “A heavy poll is expected . . . ” to “A heavy turnout is expected . . . ” can easily change ’poll’ to ’turnout’ throughout the entire document. • Such a case was reported in the British press: all the election documents of a candidate named Pollack were printed with the name Turnoutack. • A “computer failure” was blamed. This story is taken from [Newman and Lamming, 1995], pages 8–9. Beware Unix Commands • Intend to type: rm *˜ to remove Emacs backup files. • Actually type: rm * ˜ which removes everything! • And there is no undo . . . The Terminal is Dead Reported in the Human Factors Society Bulletin, 1981: • The manager of a system installation for police departments reported that one day he received the call “your terminal is dead. Come and get it.” • He suggested that the repair service should be contacted, but the caller insisted. • The terminal had two bullet holes in it. • Apparently, an officer got a “Do not understand” message on the screen once too often. Phobos 1 Never Made it to Mars From Science magazine, 1989, and reported by Norman in CACM, Jan. 1990 [Norman, 1990]: “not long after the launch, a ground controller omitted a single letter in a series of digital commands sent to the spacecraft. And by malignant bad luck, that omission caused the code to be mistranslated in such a way as to trigger the test sequence” 34 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS • The test sequence, stored in ROM, was intended to be used only when checking the spacecraft on the ground. • Phobos 1 went into a tumble from which it never recovered. • The controller was moved to other duties. Iran Air 655 Reported in [Lee, 1992]: • In 1988, the USS Vincennes shot down an Iran Air A-300 Airbus with 290 people aboard. • The Aegis weapons system aboard the Vincennes had sophisticated software for identifying and tracking potential targets. • However, the large-screen display did not show altitude information – altitude had to be read from separate consoles. • The Airbus which had levelled off at 12 500 feet, was taken to be an F-14 fighter descending from 9 000 feet. • Ironically, an escort ship with older equipment was able to read the plane’s altitude quite correctly, but could not intervene in time. And Finally. . . • A new keyboard designed to speed up access to the most commonly used feature on Windows PCs. [From the enemy.org web site http://www.enemy.org/gallery/devices.shtml, which no longer exists.] Lessons • Most failures of human-machine systems are due to poor designs which do not take account of peoples’ capabilities and fallibilities. • These are often labelled as “computer failure” or “human error” rather than design failure. 2.4 Interface Hall of Shame Examples of interface design mistakes, taken from the Interface Hall of Shame, which used to be at http://www.iarchitect.com/shame.htm but no longer exists. A partial mirror is available at http: //homepage.mac.com/bradster/iarchitect/shame.htm [Thanks to Brian Hayes from Isys Information Architects Inc. for permission to use them here.] Smallest Setting is 1% • The Internet Explorer 4.0 cache size can only be set in increments of 1% of the size of the hard disk, as shown in Figure 2.38. • To quote from user Ross Cormier: 2.4. INTERFACE HALL OF SHAME 35 Figure 2.37: A new keyboard designed to speed up access to the most commonly used feature on Windows PCs. “The smallest setting is 1%. I have a 4 Gig drive, and don’t need 40 MB of cache thank you.” Horizontal Scrolling • Humans can scan written material faster from top to bottom rather than left to right. • Vertical lists support single-item scrolling • The Internet Explorer 4.0 certificate authority selection panel uses horizontal scrolling, as shown in Figure 2.39. Two Item List Box • Visual Basic 5.0 uses a two (!) item list box. • A drop down list or radio buttons would be much better. Two Thousand Item List Box • Do not put hundreds or thousands of items into a list box, either (see Figure 2.41). • The following message, posted in a Visual Basic programmers forum on 11th December 1996, is typical: 36 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Figure 2.38: Internet Explorer 4.0 cache settings panel. Figure 2.39: Internet Explorer 4.0 certificate authority selection panel. Figure 2.40: A two-item list box in Visual Basic 5.0. 2.4. INTERFACE HALL OF SHAME 37 Figure 2.41: A two thousand item list box. Putting too many items into a list box is bad. Figure 2.42: Zoc uses multi-row tab controls. “I want to fill a list box with 2000 items ... This takes incredibly long ... over 20 minutes. Any ideas?” Multi-Row Property Sheets • Single-row property sheets (tab controls) are among the best user interface elements ever devised. • Multi-row tab controls are perhaps one of the worst interface elements ever! • Clicking one of the tabs other than from the bottom row, causes a major reorganisation of the complete set of tabs. Figure 2.42 shows an example from Zoc, a communications program. Stupid Error Messages • Roy Child writes: “I came across this message when trying to delete files from a nearly-full hard drive in Windows 95.” Avoid Breaking a Metaphor • As a means of deleting files and documents, the Macintosh trash can is a perfectly intuitive metaphor. • Unfortunately, the designers decided to extend the trash can metaphor to include the completely counterintuitive function of ejecting diskettes. • To eject a diskette, the user had to drag the diskette icon and drop it into the trash! See Figure 2.44. • Later versions of the Mac keyboard have a dedicated eject button. See Figure 2.45. • The interface was finally fixed in Mac OS X. When the user drags a diskette icon, the trash icon morphs into an eject icon. See Figure 2.46. 38 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Figure 2.43: Deleting files from an almost full hard disk in Windows 95. Ok, now I know what to do! Figure 2.44: Ejecting a diskette on the Mac by throwing it into the trash unfortunately breaks the trash can metaphor. Figure 2.45: Later versions of the Mac keyboard have a dedicated eject button. Figure 2.46: Mac OS X retains the trash can metaphor, but when the user drags a diskette icon, the trash can morphs into an eject icon. [Thanks to Tanja Kolrus for the screen shots.] 2.5. USER CENTERED DESIGN 2.5 39 User Centered Design Science Finds, Industry Applies, Man Conforms. [Motto of the 1933 Chicago World’s Fair] People Propose, Science Studies, Technology Conforms. [Don Norman’s person-centered motto for the next century] System Centered Design • What can be built easily on this platform? • What can I create from the tools available? • What do I as a developer find interesting to work on? • What do I as a developer think users need? User Centered Design The design is based upon a user’s: • abilities and needs • context • work • tasks 40 CHAPTER 2. THE PSYCHOLOGY OF USABLE THINGS Chapter 3 Usability Engineering “ When the cook tastes the soup, that’s formative assessment. When the guests taste the soup, that’s summative assessment. ” [ Robert E. Stake, 1976. [Stake, 1976] ] Usability Engineering . . . iterative process to improve usability of a system. Figure 3.1: Usability engineering. By Jay Simpson, from the cover of IEEE Computer, March 1992. References • ++ Cooper, Reimann, and Cronin; About Face 3: The Essentials of Interaction Design; Wiley, 2007. ISBN 0470084111 (com, uk) [Cooper et al., 2007] 41 42 CHAPTER 3. USABILITY ENGINEERING • + Stone, Jarrett, Woodruffe, and Minocha; User Interface Design and Evaluation; Morgan Kaufmann, March 2005. ISBN 0120884364 (com, uk) [Stone et al., 2005] • + Carol Barnum; Usability Testing and Research; Pearson Education, Oct. 2001. ISBN 0205315194 (com, uk) [Barnum, 2001] • Jakob Nielsen; Usability Engineering; Morgan Kaufman, 1994. ISBN 0125184069 (com, uk) [Nielsen, 1993b] • Deborah Mayhew; The Usability Engineering Lifecycle: A Practitioner’s Handbook for User Interface Design; Morgan Kaufman, 1999. ISBN 1558605614 (com, uk) [Mayhew, 1999] • Rosson and Carroll; Usability Engineering: Scenario-Based Development of Human-Computer Interaction; Morgan Kaufman, 2001. ISBN 1558607129 (com, uk) [Rosson and Carroll, 2001] • Larry Constantine and Lucy Lockwood; Software for Use; Addison-Wesley, 1999. ISBN 0201924781 (com, uk) [Constantine and Lockwood, 1999] • ISO 9241-11 Ergonomics requirements for office work with visual display terminals (VDTs), Part 11: Guidance on usability, 1998. [ISO, 1998] • ISO 13407 Human-centred design processes for interactive systems, 1999. [ISO, 1999] Online Resources • James Hom; The Usability Methods Toolbox. http://usability.jameshom.com/ • Jakob Nielsen; useit.com usable information technology. http://www.useit.com/ 3.1 Defining Usability The ISO defines usability as “the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use.” [ISO, 1998]. [The emphasis is mine, not part of the original definition.] The three measurable usability attributes defined by ISO [1998] are: • Effectiveness: accuracy and completeness with which users achieve specified goals. • Efficiency: resources expended in relation to the accuracy and completeness with which users achieve goals. • Satisfaction: freedom from discomfort, and positive attitudes towards the use of the product. Usability in Context Nielsen [1993b] defines usability in the context of overall system acceptability, as shown in Figure 3.2. 3.1. DEFINING USABILITY 43 Social Acceptability Utility Effectiveness Usefulness System Acceptability Cost Practical Acceptability Learnability Usability Compatibility Efficiency Memorability Errors Satisfaction Reliability Figure 3.2: A model of the attributes of system acceptability, based on Figure 1 of [Nielsen, 1993b]. Six Usability Attributes Combining the three ISO usability attributes with Nielsen’s five usability attributes, leads to the following six usability attributes: 1. Effectiveness: completeness with which users achieve their goal. 2. Learnability: ease of learning for novice users. 3. Efficiency: steady-state performance of expert users. 4. Memorability: ease of using system intermittently for casual users. 5. Errors: error rate for minor and catastrophic errors. 6. Subjective Satisfaction: how pleasant system is to use. Measuring Usability Attributes • Effectiveness: decide on definition of success. For example, number of substitution words spotted in a text, or binary measure of success (order completed or not). • Learnability: pick novice users of system, measure time to perform certain tasks. Distinguish between no/some general computer experience. • Efficiency: decide definition of expertise, get sample expert users (difficult), measure time to perform typical tasks. • Memorability: get sample casual users (away from system for certain time), measure time to perform typical tasks. • Errors: count minor and catastrophic errors made by users while performing some specified task. For example, number of deviations from optimal click path. • Satisfaction: ask users’ subjective opinion (questionnaire), after trying system for real task. 44 CHAPTER 3. USABILITY ENGINEERING 3.2 Usability Evaluation There are three types of evaluation, according to the purpose of the evaluation: • Exploratory - how is it (or will it be) used? • Predictive - estimating how good it will be. • Formative - how can it be made better? • Summative - how good is it? My definitions [Andrews, 2008] are adapted from those of several authors [Stone et al., 2005; Rubin, 1994; Lockee et al., 2002; Ellis and Dix, 2006]. Exploratory Evaluation Explores current usage and the potential design space for new designs. • Done before interface development. • Learn which software is used, how often, and what for. • Collect usage data – statistical summaries and observations of usage. Predictive Evaluation Estimates the overall quality of an interface (like a summative evaluation, but a prediction made in advance). • Done once a design has been done, but before implementation proceeds. Formative Evaluation Informs the design process and helps improve an interface during design. • Done during interface development. • Learn why something went wrong, not just that it went wrong. • Collect process data – qualitative observations of what happened and why. Summative Evaluation Assesses the overall quality of an interface. • Done once an interface is (more or less) finished. • Either compare alternative designs, or test definite performance requirements. • Collect bottom-line data – quantitative measurements of performance: how long did users take, were they successful, how many errors did they make. 3.3. THE USABILITY ENGINEERING LIFECYCLE 45 Modified Soup Analogy Extending Robert Stake’s soup analogy [Stake, 1976; Lockee et al., 2002]: “When the cook tastes other cooks’ soups, that’s exploratory. When the cook assesses a certain recipe, that’s predictive. When the cook tastes the soup while making it, that’s formative. When the guests (or food critics) taste the soup, that’s summative.” Usability Evaluation Methods The methods of usability evaluation can also be classified according to who performs them: • Usability Inspection Methods Inspection of interface design by usability specialists using heuristics and judgement (no test users). • Usability Testing Methods Empirical testing of interface design with real users. Figure 3.3 illustrates some of the different inspection and testing methods, grouped by purpose and by who performs them. 3.3 The Usability Engineering Lifecycle 1. Know the User 2. Usability Benchmarking 3. Goal-Oriented Interaction Design 4. Iterative Design: (a) Prototyping (b) Formative Usability Evaluation (Inspection and/or Testing) 5. Summative Usability Evaluation 6. Follow-up Studies The lifecycle is illustrated in Figure 3.4. 3.3.1 Know the User • Qualitative research: observation of users and interviews. • Exploratory evaluation: which software is used, how is it used, and what is it used for. • Draw up a user profile for each (potential) class of user, based on behavioural and demographic variables. • Identify user goals and attitudes. 46 CHAPTER 3. USABILITY ENGINEERING Evaluation Methods Exploratory Before Design Software Logging (or After Release) After Design Before Implementation Diary Study Observational Study Predictive Action Analysis Formative During Implementation Heuristic Evaluation Guideline Checking Thinking Aloud Cognitive Walkthrough Summative After Implementation Guideline Scoring Inspection An inspection method performed by evaluation specialists. Questionnaires Formal Experiment A/B Testing Testing A testing method performed by representative test users. Figure 3.3: Nine common evaluation methods grouped by purpose and by who performs them. 3.3. THE USABILITY ENGINEERING LIFECYCLE 47 Exploratory Evaluation Know the User Usability Benchmarking Goal-Oriented Interaction Design Predictive Evaluation Iterative Design Formative Evaluation Prototyping Summative Evaluation Follow-Up Studies Figure 3.4: The usability engineering lifecycle. Adapted from a figure kindly provided by Martin Loitzl. 48 CHAPTER 3. USABILITY ENGINEERING • Analyse workflow and context of work. • Draw up a set of typical user scenarios. See Chapter 4. 3.3.2 Usability Benchmarking • Analyse competing products or interfaces heuristically and empirically. • Set measurable usability targets for your own interface. See Chapter 5. 3.3.3 Interaction Design Goal-oriented initial design of interface. See Chapter 6. 3.3.4 Iterative Design “Design, Test, Redesign.” Build and evaluate prototype interface, then: • Severity ratings of usability problems discovered. • Fix problems → new version of interface. • Capture design rationale: record reasons why changes were made. • Evaluate new version of interface. until time and/or money runs out. A cycle of continuous improvement. Building Prototypes • Verbal description. • Paper prototype. • Working prototype. • Implementation of final design. See Chapter 7. 3.4. PLANNING USABILITY ACTIVITIES 49 Formative and Summative Usability Evaluation The usability evaluation methods are described according to who performs them: • Usability inspection methods: Chapter 8. • Usability testing methods: Chapter 9. 3.3.5 Follow-Up Studies Important usability data can be gathered after the release of a product for the next version: • Specific field studies (interviews, questionnaires, observation). • Standard marketing studies (what people are saying in the newsgroups and mailing lists, reviews and tests in magazines, etc.). • Instrumented versions of software → log data. • Analyse user complaints to hotline, modification requests, bug reports. 3.4 Planning Usability Activities 1. Prioritise activities. 2. Write down explicit plan for each activity. 3. Subject plan to independent review (e.g. colleague from different project). 4. Perform pilot activity with about 10% of total resources, then revise plan for remaining 90%. [Always perform a pilot study!] 50 CHAPTER 3. USABILITY ENGINEERING Chapter 4 Know the User “ I’m a very selfish designer: when I design sofware, I design it for me. And so my first task is to become you. ” [ Bruce Tognazzini, The Front Desk, BBC Video, 1995. ] Qualitative research is used to determine user characteristics, goals, and context of use. References • + JoAnn Hackos and Janice Redish; User and Task Analysis for Interface Design; Wiley, 1998. ISBN 0471178314 (com, uk) [Hackos and Redish, 1998] • + Mike Kuniavsky; Observing the User Experience: A Practitioner’s Guide to User Research; Morgan Kaufmann, April 2003. ISBN 1558609237 (com, uk) [Kuniavsky, 2003] • Hugh Beyer and Karen Holtzblatt; Contextual Design : A Customer-Centered Approach to Systems Designs; Morgan Kaufmann, 1997. ISBN 1558604111 (com, uk) [Beyer and Holtzblatt, 1997] • Catherine Courage and Kathy Baxter; Understanding Your Users; Morgan Kaufmann, 2004. ISBN 1558609350 (com, uk) [Courage and Baxter, 2004] • Alan Cooper and Robert Reimann; About Face 2.0: The Essentials of Interaction Design; Wiley, 2003. ISBN 0764526413 (com, uk) [Cooper and Reimann, 2003] • Kate Gomoll, Ellen Story Church, and Eric Bond; The Field Study Handbook; UIE, June 2007. http://www.uie.com/reports/field_study_handbook/ 4.1 Classifying Users Users can be classified according to their: • experience • educational level • age • amount of prior training, etc. 51 CHAPTER 4. KNOW THE USER Ex of pe Sy rt U st se em r Knowledge of Domain 52 Ignorant about Domain Extensive Computer Experience N o of vic Sy e st Use em r Minimal Computer Experience Figure 4.1: The three main dimensions on which user experience varies: experience of computers in general, understanding of the task domain, and expertise in using the specific system. From Figure 3 of [Nielsen, 1993b]. Categories of User Experience User experience can be thought of along three dimensions, as shown in Figure 4.1. Learning Curves • Some systems are designed to focus on learnability. • Others emphasise efficiency for proficient users. • Some support both ease of learning and an “expert mode” (for example rich menus and dialogues plus a command/scripting language), and thus attempt to ride the top of the curves in Figure 4.2. Most Users are Perpetual Intermediates The experience level of people using computer software tends, like most population distributions, to follow the classical statistical bell curve (normal distribution). In terms of using a software interface, the bell curve represents a snapshot in time: • Beginners do not remain beginners for long. • The difficulty of maintaining a high level of expertise means that experts fade over time. • Most users gravitate over time towards intermediacy. Most users are neither beginners nor experts: they are perpetual intermediates. 4.2. RESEARCH THE FRAMES OF REFERENCE 53 Efficiency Focus on Expert User Focus on Novice User Time Figure 4.2: Learning curves for hypothetical systems focusing on the novice user (easy to learn, but less efficient to use) and the expert user (harder to learn, but then highly efficient). From Figure 2 of [Nielsen, 1993b]. 4.2 Research the Frames of Reference Conduct interviews with: • Project staff (managers, programmers, marketing people) who are in charge of developing the software. • Subject matter and domain experts. • Customers (the purchaser of the product, not necessarily the same as the end user). to determine values, expectations, issues, and constraints. Interviewing Project Staff • One-on-one interviews. • Try to discover: – vision of the product. – budget and schedule. – technical constraints. – perceptions of who users might be. Interviewing Subject Matter Experts (SMEs) • Often hired externally by project manager. • Provide knowledge of complex domains, regulations, industry best practice. • Often lean towards expert user perspective (rather than intermediate). 54 CHAPTER 4. KNOW THE USER Interviewing Customers • Customers are the people who make the decision to purchase. • For consumer products, customers are often the same as users. • For business settings, customers are rarely actually the users of a product. • Try to discover the customer’s: – goals in purchasing the product – frustrations with current solutions – decision process for purchasing – role in installation and maintenance 4.3 Research the End User The actual users of a product should always be the main focus of the design effort. • Most people are incapable of accurately assessing their own behaviour [Pinker, 1999]. • Rather than talk to users about how they think they behave, it is better to observe their behaviour first-hand. • And then ask clarifying questions in the context of use. Ethnographic Interviews A combination of immersive observation and directed interview techniques. • Observe the user using their current tools in their normal environment. • Interviewer assumes the role of an apprentice learning from the master craftsman (user). • Alternate between observation of work and discussion of its structure and details. Identifying Candidate Users Designers must capture the range of user behaviours regarding a product. • What sorts of people might use this product? • How might their needs vary? • What ranges of behaviour might be involved? • Which kinds of environment might be involved? Try to interview some people from each different group. 4.3. RESEARCH THE END USER 55 Examples Whom would you interview if you were designing: • An in-flight entertainment system? • A corporate help desk? • A complete hospital management system? • A mobile phone with email capability? Conducting an Ethnographic Interview • In actual workplace/environment. • 45-60 minutes. • No third parties (supervisors or clients). • Focus on understanding: – Overall goals – Current tasks – Constraints and exceptions – Problems needing solution (where does it hurt?) – Broader context – Domain issues – Vocabulary • Ask permission to take a few photographs of the user and their workplace (for creating personas). Patterns of Use When interviewing users, we are trying to discover patterns of use: • Business products: Patterns of use are generally based on job responsibilities. • Consumer products: Patterns of use are generally based on lifestyle (age, gender, occupation, etc). Being an Active Listener A good interviewer is an active listener: • Use open body language: lean forward, hand under chin, arms open, eye contact. • Use minimal encouragers: brief verbal cues (hmmm, uh-huh, oh?), nodding, tilting head sideways. • Ask open-ended questions (how, when, what, why) to encourage elaboration. • Use closed questions (can you, will you, do you) with yes/no or simple fact answer to clarify your understanding. • Summarise to check you understand the important points: “So it sounds like the key points are...”. 56 CHAPTER 4. KNOW THE USER General Flow of Interview for Business Product • Introductions. • Why we’re here: We’ve been asked to design/improve X. • What we’ll ask: your day, your background, your frustrations. • Tell us about your responsibilities and your typical workday. • Drill into specific tasks. • How is existing product (if any) involved in those tasks. • Relationships with other people and processes. • Goals. • Follow up on interesting points. • Wrap-up. Good General Questions • What do you spend most of your time on? [task priority] • What things waste your time? [opportunity] • Where does it hurt? [opportunity] • What makes a good work day? A bad one? [goals] • What kind of training do you have? [support to provide] • What are the most important things you do? [priorities, goals] • What information helps you make decisions? [info to provide] Chapter 5 Usability Benchmarking Usability benchmarking: • how usable is the competition? • how much better should your interface be? • what is your likely return on investment? References • Randolph Bias and Deborah Mayhew (Eds.); Cost-Justifying Usability; 2nd Edition, Morgan Kaufmann, April 2005. ISBN 0120958112 (com, uk) [Bias and Mayhew, 2005] • Nielsen Norman Group; Usability Return on Investment; Nielsen Norman Group, 2003. http: //www.nngroup.com/reports/roi/ • Eric Schaffer; Institutionalization of Usability; Addison-Wesley, 2004. ISBN 032117934X (com, uk) [Schaffer, 2004] Online Resources • Jakob Nielsen; Return on Investment for Usability Alertbox, January 2003. http://www.useit. com/alertbox/20030107.html • Peter Merholz and Scott Hirsch; Report Review: Nielsen/Norman Group’s Usability Return on Investment Boxes and Arrows, July 2003. http://www.boxesandarrows.com/archives/report_ review_nielsennorman_groups_usability_return_on_investment.php • Aaron Marcus; Return on Investment for Usable User Interface Design: Examples and Statistics; http://www.amanda.com/resources/ROI/AMA_ROIWhitePaper_28Feb02.pdf 5.1 Competitive Analysis Competitive analysis of competing systems: • Determine the current state of the art and decide how far to raise the bar. 57 58 CHAPTER 5. USABILITY BENCHMARKING Project size (person-years) Actual usability budget (% total) Ideal usability budget (% total) Actual usability effort (person-years) Ideal usability effort (person-years) Q1 11 4 6 1.0 1.7 Median 23 6 10 1.5 2.3 Q3 58 15 21 2.0 3.8 Table 5.1: Survey of the usability budgets of 31 projects having some usability activities. From Table 1 of [Nielsen, 1993b]. • Analyse competing products or interfaces heuristically or empirically. • “Intelligent borrowing” of ideas from other systems. 5.2 Set Usability Targets • Decide in advance on usability metrics and desired level of measurable usability (usability targets). For example: – The current system exhibits 4.5 errors per hour on average for an experienced user. The target for the new version is less than 3 errors per hour. – From competitive analysis, on the main competing web site, novice users take 8 mins. and 21 secs. on average to book a flight. The target for our new web site is 6 mins. 5.3 Return on Investment Estimate return on investment (ROI) by performing a financial impact analysis: • Compare potential savings based on loaded cost of users to to the estimated cost of the usability effort. Jakob Nielsen concludes [Nielsen, 2003] that current best practices call for devoting about 10% of a project’s budget to usability. See Table 5.1. Chapter 6 Goal-Oriented Interaction Design “ What should be in the designer’s mind at the start of an interface project? That’s simple. Nothing. ” [ Don Norman, The Front Desk, BBC Video, 1995. ] References • ++ Alan Cooper et al; About Face 3: The Essentials of Interaction Design; Wiley, 2007. ISBN 0470084111 (com, uk) [Cooper et al., 2007] • + John Pruitt and Tamara Adlin; The Persona Lifecycle; Morgan Kaufmann, 2006. ISBN 0125662513 (com, uk) [Pruitt and Adlin, 2006] • + Steve Mulder and Ziv Yaar; The User Is Always Right: A Practical Guide to Creating and Using Personas for the Web; New Riders, 2006. ISBN 0321434536 (com, uk) [Mulder and Yaar, 2006] • + Ellen Isaacs and Alan Walendowski; Designing from Both Sides of the Screen; New Riders, Dec. 2001. ISBN 0672321513 (com, uk) [Isaacs and Walendowski, 2001] • Joel Spolsky; User Interface Design For Programmers; APress, June 2001. ISBN 1893115941 (com, uk) [Spolsky, 2001] • + Alan Cooper; The Inmates are Running the Asylum; Sams, 2004. ISBN 0672326140 (com, uk) [Cooper, 2004] Online Resources • Alan Cooper; Cooper Interaction Design. http://www.cooper.com/ • Kim Goodwin; Getting from Research to Personas: Harnessing the Power of Data; http://www. cooper.com/content/insights/newsletters/2002_11/getting_from_research_to_personas. asp • Kim Goodwin; Perfecting Your Personas; http://www.cooper.com/content/insights/ newsletters/2001_07/perfecting_your_personas.htm • Dan Saffer; Persona Non Grata; http://adaptivepath.com/publications/essays/archives/ 000524.php 59 60 CHAPTER 6. GOAL-ORIENTED INTERACTION DESIGN Computers Incredibly fast Error free Deterministic Apathetic Literal Sequential Predicatable Amoral Stupid Humans Incredibly slow Error prone Irrational Emotional Inferential Random Unpredictable Ethical Intelligent Table 6.1: There are incredible differences between computers and the humans who have to use them. • David Anderson; uidesign.net. http://www.uidesign.net/ • Joel Spolsky; User Interface Design For Programmers; http://www.joelonsoftware.com/ uibook/fog0000000249.html • morgueFile; http://morguefile.com/ • stock.xchng; http://www.sxc.hu/ • OPENPHOTO; http://openphoto.net/ • Visipix; http://visipix.com/ • Flickr; http://www.flickr.com/ • Larry Bercow Photography; http://www.bercowstudio.com/ • Free Images; http://www.freeimages.co.uk/ • Google Image Search; http://images.google.com/ (but beware of copyright!). • Wikipedia free image resources; http://en.wikipedia.org/wiki/Public_domain_image_ resources Computers Versus Humans Computers do not work like humans (see Table 6.1). • One part of software, the inside, must clearly be written in harmony with the demands of silicon. • Equally, the other side of software, the outside, must be written in harmony with the demands of human nature. Programmers are Different Programmers (“homo logicus”) think and behave differently from normal humans (homo sapiens) and most users. See Table 6.2. Programmers are good at designing the inside of software, interaction designers should design the outside. 61 Programmer Wants control, will accept some complexity. Wants to understand, will accept some failure. Concerned with all possible cases, will accept advance preparation. User Wants simplicity, will accept less control. Wants success, will accept less understanding. Concerned with probable cases, will accept occasional setbacks. Table 6.2: Programmers (“homo logicus”) think and behave differently from normal humans (homo sapiens). They are more in tune with the needs of computers. Interaction Design versus Interface Design Interface design suggests an interface between code on one side and users on the other side, passing messages between them. It gives programmers a licence to code as they please, because the interface will be slapped on when they are done. Interaction design refers to function, behaviour, and final presentation. Goal-Oriented Interaction Design Designing software based on an understanding of human goals. What is a goal? • A goal is a final purpose or aim, an objective. • Tasks are particular ways of accomplishing a goal. There may be multiple ways of achieving a goal. Tasks are not Goals • Goal: Get something to eat. • Task: Go to the restaurant around the corner. Or • Task: Call the pizza delivery service. Or • Task: Go to the supermarket, buy ingredients, and cook for myself. Too often, software designers focus on simplifying a task, rather than accomplishing a goal. Tasks are a means to an end, not an end in themselves. Tasks Change with Technology Tasks change with technology, goals do not: • Year 2000 – Goal: Get to work. – Task: Take the tram. 62 CHAPTER 6. GOAL-ORIENTED INTERACTION DESIGN Personal Goals Do not look stupid. Not make mistakes. Get adequate amount of work done. Have fun. Corporate Goals Increase profit. Increase market share. Defeat competition. Hire more people. Go public. Table 6.3: Personal and corporate goals are different. Both must be taken into account for software to succeed, but personal goals will always dominate. – Task: Take a taxi. – Task: Drive in traffic. • Year 3000 – Goal: Get to work. – Task: Press the teleport button. – Task: Fly with jet pack. Personal and Corporate Goals Personal and corporate goals are different (See Table 6.3). • Both are the highest expression of goals for their respective owners (both must be taken into account). • But people are doing the work, and their personal goals will always take precedence (although they are rarely discussed, precisely because they are personal). The Interaction Design Process 1. Interview users 2. Create personas 3. Define their goals 4. Create concrete scenarios 5. Move to a design solution The Design Team Two designers in core team: • Designer: generates ideas, leads the process. • Design Communicator: articulates half-formed ideas, writes design spec. 6.1. CREATING PERSONAS 63 Figure 6.1: The term “user” is elastic and is liable to be bent and stretched by the programmer to the needs of the moment. 6.1 Creating Personas From the insight you gained in your interviews, you now invent user archetypes to represent the main user groups of your product. In other words, you make up pretend users and design for them. The Elastic User All too often, the term “user” is bent and stretched by the programmer to adapt to the needs of the moment (see Figure 6.1): • When the programmer finds it convenient to dump the user into the Windows file system, the elastic user is defined as an accommodating, computer-literate power user. • Other times, when the programmer finds it convenient to step the user through a difficult process with a mindless wizard, the elastic user is redefined as an obliging first-time novice. Never refer to “the user”, instead refer to a very specific individual, a persona. Do Not Design for the Average User • Designing for the “average” user produces a design to please no-one, like the jumble car in Figure 6.2. • Differentiate primary kinds of user and design for them, like the cars in Figure 6.3. What is a Persona A persona is a prototypical user: • An imaginary, but very specific, example of a particular type of user. 64 CHAPTER 6. GOAL-ORIENTED INTERACTION DESIGN Figure 6.2: The jumble car was designed for the “average” driver. Figure 6.3: Cars are designed to appeal to different kinds of drivers with different needs and goals. • Not “real”, but hypothetical. A persona is used to role-play through an interface design and check if the design would meet the needs of such a user. A Good Persona • A good persona is not “average”, but typical and believable. • If the set of users interviewed were somehow plotted according to their characteristics as a cloud of points, the best ones to base personas on would be the ones around the edges. • If our design satisfies the hard cases around the edges, the ones in the middle should be able to use the interface as well. Define the Persona Precisely • Specify a name, age, face, and quirky, believable detail. • For faces, use stock photos from CD-ROM or the internet, or photographs taken during user interviews. • It is more important to define the persona in great and specific detail, so that it cannot wiggle under the pressure of development, than that the persona be exactly the right one. 6.1. CREATING PERSONAS 65 Figure 6.4: The InFlight seat console. Finding Primary and Secondary Personas • Start off with a larger set of personas. • Combine or throw out redundant personas. • A primary persona will not be satisfied with a design for someone else. – If there are multiple personas with radically different needs, there are multiple primaries. – Each primary gets their own interface. • A secondary persona is mostly satisfied with a primary’s interface, but has a specific additional need. Case Study: In-Flight Entertainment System Fictional example based on example in [Cooper, 2004], an inflight entertainment system called InFlight for Zoom Airways. At each seat a touch-screen video console (see Figure 6.4): • 36 films in five categories, 36 music channels, news, childrens shows, games, shopping. • computers + large hard disks in front of the plane. • true video on demand – each passenger can start, pause, and rewind programmes independently. 66 CHAPTER 6. GOAL-ORIENTED INTERACTION DESIGN Name: Clevis McQuinn Age: 63 Class: Economy Clevis was born and still lives in a small town in Texas. He only flys once or twice a year to visit his daughter who lives in Boston. Clevis might be old, but he is still spry. He is slightly embarassed about the touch of arthritis in his hands, but his mind is still very sharp. Clevis does not own a computer and does not know how to use one. He is firmly of the opinion that you can get by without one. Clevis had to start wearing glasses about 5 years ago, because his eyesight was starting to fail him. Name: Marie Dupart Age: 31 Class: Business Marie was born in France, but has been living and working in the USA for 6 years. She is bilingual, but English is her second language. Marie travels on business several times times a year. She is a self-confident young woman, who is not afraid of modern gadgetry. She owns a PDA and an iPod. Marie does much of her shopping online. She is also very interested in the latest show business gossip in the entertainment media. Name: Chuck Burgstein Age: 52 Class: First Chuck is a resident of New York who flies almost every week. He is a member of the 100,000-mile club. He has an extremely hectic lifestyle and spends more than 100 nights a year in hotel rooms. Chuck expects service here and now and has little tolerance for condescending or timeconsuming activities. Chuck has strong opinions, which he is not shy to express. Even if he is usually right, other people do find his in-your-face manner somewhat irritating. Name: Erin Scott Age: 9 Class: Economy Erin lives Austin, Texas and is going to stay with her aunt and uncle in upstate New York for two weeks. She is a little bit nervous, but also excited about travelling unacompanied for the first time. Erin likes drinking fizzy orange pop. At home she will often spend hours and hours on her computer playing Sims2. Table 6.4: The four main passenger personas. 6.1. CREATING PERSONAS 67 Name: Brent Coverham Age: 33 Position: Purser Brent is new to Zoom, having spent 7 years at another airline. Name: Amanda Surrey Age: 28 Position: Flight attendant After safety, Amanda must focus on assuring that each passenger has the best experience possible. She uses the InFlight console at the flight attendant’s station to deal with any problems during flight. Name: Molly Springer Age: 41 Position: Ground staff Molly is responsible for uploading new content to the InFlight system. Name: Joseph C. Wong Age: 47 Position: Pilot Born in Seattle to Chinese parents, Joseph transferred to Zoom Airways from the military. Name: Max “Hoppy” Hooper Age: 51 Position: Mechanic Hoppy is an aircraft enthusiast who has been working at Zoom for 15 years. Hoppy services and maintains the InFlight system, fixing any bugs, wiring, etc. Table 6.5: The five main employee personas. 68 CHAPTER 6. GOAL-ORIENTED INTERACTION DESIGN Case Study: Two Separate Interfaces • One for the passengers in the seat console. • A different one for employees in the attendant’s station. Case Study: Who are the Primary Passenger Personas? The seat console interface has to satisfy Chuck, Erin, Marie, and Clevis, while at the same time not making any of them unhappy. • Erin knows wanting to play games is something special, so she does not mind pressing a few extra buttons to get them. • Chuck knows his vast flying experience has earned him some shortcuts, but he does not mind investing a little effort into remembering those special commands. • Marie is similar to Chuck, and both would be annoyed by time-consuming training screens for new users. • Clevis is the golden nugget, the primary persona. A menu bar or dialogue box would instantly lose Clevis. With arthritis, any complex manipulation is out of the question. An interface designed for Clevis will be acceptable to all the others, as long as their special needs are accommodated somewhere in the interface. Case Study: Designing for Clevis Clevis can not and will not “navigate”, so there can be only one screen: • Horizontal scrolling panoply of film posters and album covers. • A large rotating knob (a “data wheel”) physically below the screen, which can be spun like a radio wheel. • Clevis views the posters as if strolling past, no need to even think in terms of film categories. • Navigation bar across bottom of screen, feedback where we are and with jump scrolling for Chuck. See Figure 6.5. 6.2 Defining Goals for each Persona Goals and personas co-exist. A persona exists to achieve his goals, a goal exists to give meaning to a persona. Define the goals of each persona. 6.3 Defining Scenarios for each Persona A scenario is a precise description of a persona using an interface to achieve a goal. 6.4. MOVING TO A DESIGN SOLUTION 69 Figure 6.5: The InFlight final design. • Daily Use Scenarios: the primary actions the user will perform. These need the most robust design. • Necessary Use Scenarios: More occasional, infrequent actions, which are necessary from time to time. • Edge Case Scenarios: Loved by programmers, these can largely be ignored during the design process. As the design progresses, play act the personas through the scenarios to test the validity of the design. 6.4 Moving to a Design Solution Parallel Design • If time and resources allow, explore design alternatives. • Have several design teams work independently, then compare draft designs (see Figure 6.6). Brainstorm • Meet away from usual workplace (different building, hut in the mountains). • Brainstorm with mixed team (engineers, graphic designer, writer, marketing types, usability specialist, one or two representative users). 70 CHAPTER 6. GOAL-ORIENTED INTERACTION DESIGN Original Product Concept Parallel Design Sketches First Prototype Iterative Design Versions Released Product Figure 6.6: The relationship between parallel and iterative design. The first prototype is based on ideas from parallel design sketches. From Figure 8 of [Nielsen, 1993b]. • Use plenty of paper. Cover the walls with it! • Draw. Scribble. Use lots of coloured pens. • Be stupid. • Go crazy, build on the insane, think laterally (see Figure 6.7). • Three rules during brainstorming: 1. No one is allowed to criticise another’s ideas. 2. Programmers must not say it can’t be implemented. 3. Graphic designers must not laugh at programmers’ drawings. • Only after brainstorming, organise ideas and consider their practicality and viability. Adapted from [Tognazzini, 1992], page 67. Four Techniques for Getting Unstuck • Pretend It’s Magic: If it were magic, it would do X. If we can not do X, how close can we get? • Pretend It’s Human: What response would the persona expect from a human? • Getting Another Brain: 15-minute rule. If a team is stuck for more than 15 minutes, ask another designer for help. 6.5. FOLLOW CONVENTIONS 71 Ridiculous Ludicrous Impossible A Great Idea! Do-able Practical Possible Same Old Stuff You Are Here Figure 6.7: Lateral Thinking. Build on the crazy to generate new ideas [from Edward de Bono] • Renaming: Sometimes, a lack of common vocabulary is the problem. In this case, give elements new names in a silly theme (types of cheese, mountain ranges), define what they mean, and give them real names later. Pretend It’s Magic What would these things do if they were magic? • TV/VCR entertainment system • Telephone/voicemail • Calendar software • Microsoft Windows Quick Surveys for Menu Organisation A simple user survey can quickly tell you where users would expect to find certain functionality. Figure 6.8 shows a survey to place word processing functions. [This is, in fact, a quick and dirty version of a closed card sorting test.] 6.5 Follow Conventions Following the standard way of doing things is generally good: • Users can then transfer knowledge as they move between applications. • Only break the convention for good reason. Link Styles • Users should not have to guess where they can click (or have to scan the screen with the mouse to see what is clickable). • For textual links, use coloured and underlined text (and do not underline non-link text). 72 CHAPTER 6. GOAL-ORIENTED INTERACTION DESIGN Under which pull-down menu would you most expect to find each of the word processing tasks below. File Edit View Insert Format Utilities Macro Window 1. Search for a word: __________ 2. Create a header: __________ 3. Create an index entry: __________ 4. Set up your document preferences: __________ 5. Repeat an annotation: __________ 6. Paste another file into your current file: __________ 7. Use italics: _______________ 8. Show summary information about your document: __________ 9. Switch to another document: __________ 10. Show all annotations in the document: __________ 11. Repaginate the document: __________ 12. Set up your printer: __________ Figure 6.8: A quick user survey on menu organisation. 6.5. FOLLOW CONVENTIONS 73 Figure 6.9: Jakob Nielsen’s web site useit.com uses the conventional link sytle of blue underlined for unvisited links and purple underlined for visited links [Nielsen, 2005]. • Distinguish between visited and unvisited links. • By convention, unvisited links are blue underlined, visited links are purple underlined. This is is a good default choice. See Figure 6.9. • If you do choose to use a different link style, at least use it consistently across your site. See Figure 6.10. An Asterisk Means a Required Field • In the context of a web form, a field marked with an asterisk (*) has come to mean a required field. • Do not change this meaning arbitrarily, as Avis did on their web site in 2005, shown in Figure 6.11. • These three fields were the only three optional fields on their site. • Rather than place asterisks meaning required next to dozens of other fields (a terrible waste of asterisks), Avis’ web designers thought it reasonable to redefine the meaning of an asterisk to indicate an optional field. • Breaking the convention caused unnecessary confusion to their users. • Avis now (11 Mar 2011) follows the conventional meaning and uses an asterisk to indicate a required field, as shown in Figure 6.12. • See Jared Spool’s article [Spool, 2005]. 74 CHAPTER 6. GOAL-ORIENTED INTERACTION DESIGN Figure 6.10: Non-Standard and inconsistent link styles at orf.at. There are three different styles for links: white, bold black, and bold blue-grey. Bold black is used inconsitently within itself: the first bold black text (Ausland) is not clickable, the second (Weitere Proteste. . . ) is, the third (Erster Minister. . . ) is not. Users can no longer predict what is a link and what is not. Figure 6.11: In 2005 the Avis web site used an asterisk to indicate an optional field, breaking the convention that an asterisk means required. This caused confusion to their users. [Image used with kind permission of Jared Spool [Spool, 2005]] 6.5. FOLLOW CONVENTIONS 75 Figure 6.12: Avis now (11 Mar 2011) follows the conventional meaning and uses an asterisk to indicate a required field. Platform Conventions Platform conventions are the accepted way of doing things on a particular platform: • Macintosh Human Interface Guidelines, Apple Computer, Jan. 1993 [Apple Computer, 1992]. • Microsoft Windows User Experience, Microsoft Press, September 1999 [Microsoft, 1999]. • Java Look and Feel Design Guidelines, Sun Microsystems, July 1999 [Sun Microsystems, 1999]. They are often supported by widget libraries of shared code. Design Patterns Look for design patterns for your particular situation: platform-independent tried-and-tested solutions to common design problems (for example, the shopping cart design pattern for an e-commerce web site). 76 CHAPTER 6. GOAL-ORIENTED INTERACTION DESIGN Chapter 7 Prototyping “ There’s a mantra at IDEO: “Never go to a meeting without a prototype.” At whatever stage of development, one week, one month, or 6 months. ” [ Tim Brown, President, IDEO, speaking at CHI 2004 in Vienna. ] Perform usability evaluation and get feedback as early as possible in the design cycle by building and evaluating prototypes. In increasing order of complexity: • Verbal Prototypes: textual description of choices and results. • Paper Prototypes: – Low-Fidelity: hand-drawn sketches. – High-Fidelity: more elaborate printouts. • Interactive Sketches: interactive composition of hand-drawn sketches. • Working Prototypes: interactive, skeleton implementation. Finally, throw prototypes away and implement final design. References ++ Carolyn Snyder; Paper Prototyping; Morgan Kaufmann, 2003. ISBN 1558608702 (com, uk) [Snyder, 2003] + Bill Buxton; Sketching User Experiences; Morgan Kaufmann, 2007. ISBN 0123740371 (com, uk) [Buxton, 2007] • Marc Rettig; Prototyping for Tiny Fingers; CACM, 37(4), 1994. [Rettig, 1994]. • Carolyn Snyder; Using Paper Prototypes to Manage Risk; Software Design and Publisher Magazine, 1996. http://www.uie.com/paper.htm • Snyder and Lahti; Paper Prototyping Tricks; 12 min. videotape. User Interface Engineering, 1995. http://www.uie.com/ • Jakob Nielsen; Paper Prototyping: A How-To Training Video; 32 min. video (DVD). Nielsen Norman Group, 2003. http://www.nngroup.com/reports/prototyping/ 77 78 CHAPTER 7. PROTOTYPING Figure 7.1: Paper prototype of IICM on Air. Online Resources • Paper Prototypes: Still Our Favorite; User Interface Engineering, 2000. http://www.uie.com/ prototyp.htm • Matthew Klee; Five Paper Prototyping Tips; User Interface Engineering, 2000. http://www.uie. com/paperproto.htm 7.1 Verbal Prototype Simple textual description of choices and results. 7.2 Low-Fidelity Paper Prototypes • Paper prototypes simulate screen and dialogue elements on paper. • First hand-drawn sketches (lo-fi), later perhaps more elaborate printouts (hi-fi). • Early usabilty feedback with throwaway designs: maximum feedback for minimum effort! • Greeking (drawing squiggly lines) is used to represent text which would otherwise be a distraction. • Figures 7.1 and 7.2 show paper and working prototypes for an online radio station. Paper Prototype of Customer Information Terminal • Design interface for customer information terminal to be placed in branches of the (fictional) Northumberland Bank. • Specifically prototype the loans section: tasks include information about loans and calculation of loan repayments. 7.3. HIGH-FIDELITY PAPER PROTOTYPES 79 Figure 7.2: Working prototype of IICM on Air. • Figures 7.3, 7.4, and 7.5 show three of the paper prototypes developed. • Thanks to Cliff Brown, University of Northumbria at Newcastle, for permission to use these images. 7.3 High-Fidelity Paper Prototypes • Elaborate screen designs created with drawing editors such as Adobe Illustrator or Corel Draw. • Printed out in colour. • The often look too much like a finished design, and not enough like a prototype. • Users tend to comment on the choice of fonts and colours, rather than the flow through the application. 7.4 Interactive Sketches • Scan in hand-drawn interface sketches. • Assemble interactive prototype with clickable elements (say with Macromedia Director). • Retains throwaway, casual look to encourage criticism and discussion, as shown in Figure 7.6. • For example, Chris Edwards’ Sketchy Thing [Edwards, 1999] and Marc Rettig’s Interactive Sketch [Rettig, 1999] 80 CHAPTER 7. PROTOTYPING Figure 7.3: Paper prototype 1 for a customer information terminal. Figure 7.4: Paper prototype 2 for a customer information terminal. 7.4. INTERACTIVE SKETCHES Figure 7.5: Paper prototype 3 for a customer information terminal. Figure 7.6: An interactive sketch made in Shockwave. Screen designs sketches are scanned and assembled into an interactive prototype with Macromedia Director. Screenshot taken from Chris Edwards’ Sketchy Thing [Edwards, 1999]. 81 82 CHAPTER 7. PROTOTYPING 7.5 Working Prototypes • Simple algorithms: ignore special cases. • Fake data: similar data, images instead of video, etc. • Wizard of Oz: human expert operating behind the scenes to simulate interface responses. Prototyping Tools • DENIM; http://dub.washington.edu/denim/ • Axure; http://www.axure.com/ • Balsamiq Mockups; http://balsamiq.com/ • Microsoft Expression SketchFlow; http://www.microsoft.com/expression/products/Sketchflow_Overview.aspx • HotGloo http://www.hotgloo.com/ Dimensions of Working Prototypes Working prototypes cut down on either the number of features, or the depth of functionality of features: • Vertical Prototype: in-depth functionality for a few selected features. • Horizontal Prototype: full interface features, but no underlying functionality. • Scenario Prototype: only features and functionality along the specific scenarios or paths through the interface which are to be evaluated. These varieties of prototype are illustrated in Figure 7.7. 7.6 Implementation Implement final design. Competitive analysis of software components: • Use existing interface framework as far as possible (Motif, MS-Windows, Java Swing) – saves a lot of work. • Use existing components and applications rather than re-inventing the wheel. 7.6. IMPLEMENTATION 83 Features Horizontal Prototype V e r t i c a l P r o t o t y p e Full System Functionality Scenario Prototype Figure 7.7: Working prototypes vary according to the breadth or depth of features implemented. From Figure 9 of [Nielsen, 1993b]. 84 CHAPTER 7. PROTOTYPING Chapter 8 Usability Inspection Methods Inspection of interface design using heuristic methods (based on analysis and judgement rather than experiment). 1. Heuristic Evaluation: A small team of evaluators inspects an interface using a small checklist of general principles and produces an aggregate list of potential problems. 2. Guideline Checking: An evaluator checks an interface against a detailed list of specific guidelines and produces a list of deviations from the guidelines. 3. Cognitive Walkthrough: A small team walks through a typical task in the mind set of a novice user and produces a success or failure story at each step along the correct path. [analyses learnability] 4. Guideline Scoring: An evaluator scores an interface against a detailed list of specific guidelines and produces a total score representing the degree to which an interface follows the guidelines. 5. Action Analysis: An evaluator produces an estimate of the time an expert user will take to complete a given task, by breaking the task down into ever smaller steps and then summing up the atomic action times. [analyses efficiency] References • Jakob Nielsen and Robert L. Mack (Eds.); Usability Inspection Methods; John Wiley, 1994. ISBN 0471018775 (com, uk) [Nielsen and Mack, 1994] Would You Use Untested Software? Would you knowingly use untested software? • How many of you have written programs that are used by other people? • How many of you have watched or observed users using your software? • How many of you actually evaluated or tested your interface before it was used? • In practice, most software developers do not actually conduct any kind of usability evaluation [due to perceived expense, lack of time, lack of expertise, lack of inclination, or lack of tradition]. 85 86 CHAPTER 8. USABILITY INSPECTION METHODS 8.1 Heuristic Evaluation First described in [Nielsen and Molich, 1990]. Small team of evaluators (usually usability specialists) systematically checks interface design against small set of recognised usability principles (the “heuristics”). Online Resources • Jakob Nielsen; Heuristic Evaluation; http://www.useit.com/papers/heuristic/ Usability Heuristics Revised list of usability heuristics from [Nielsen, 1994]. The category names in brackets are the original names of the corresponding categories from [Nielsen and Molich, 1990], in those cases where they are different. 1. Visibility of System Status [Feedback] The system should always keep users informed about what is going on, through appropriate feedback within reasonable time. For example: busy cursor [1–10s], progress indicator [>10s]. 2. Match Between System and the Real World [Speak the Users’ Language] The system should speak the users’ language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order. Match users’ mental model. Beware of misleading metaphors. 3. User Control and Freedom [Clearly Marked Exits] Users often choose system functions by mistake and will need a clearly marked “emergency exit” to leave the unwanted state without having to go through an extended dialogue. Support undo and redo. 4. Consistency and Standards [Consistency] Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions. 5. Error Prevention Even better than good error messages is a careful design which prevents a problem from occurring in the first place. For example: select file from menu rather than typing in name, confirmation before dangerous actions, beware of modes, avoid similar command names. 6. Recognition rather than Recall Make objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate. Users’ short-term memory is limited. Provide examples, default values, easily retrievable instructions. 8.1. HEURISTIC EVALUATION 87 7. Flexibility and Efficiency of Use [Accelerators] Accelerators – unseen by the novice user – may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users. Allow users to tailor frequent actions. For example: abbreviations, command keys, type-ahead, edit and reissue previous commands, menu of most recently used files, macros. 8. Aesthetic and Minimalist Design [Minimalist Design] Dialogues should not contain information which is irrelevant or rarely needed. Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility. “Less is more” 9. Help Users Recognise, Diagnose, and Recover from Errors [Good Error Messages] Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution. Phrase error messages defensively, never blame the user. Multilevel messages. Link to help system. 10. Help and Documentation Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user’s task, list concrete steps to be carried out, and not be too large. Liberal use of examples. Limits on Response Times • 0.1 sec.: is the limit so that the system appears to react instantaneously. Important for direct manipulation, virtual world navigation. • 1 sec.: is the limit so that the user’s flow of thought stays uninterrupted. Display a busy cursor if things will take longer than 1 sec. • 10 secs.: is the limit for keeping the user’s attention on the task at hand. Display a progress indicator if things will take longer than 10 secs. From Section 5.5 of [Nielsen, 1993b] and [Nielsen, 1993a]. Performing a Heuristic Evaluation • Design may be verbal description, paper mock-up, working prototype, or running system. [when evaluating paper mock-ups, pay special attention to missing dialogue elements!] • Provide evaluators with checklist of usability heuristics. • Optionally provide evaluators with some domain-specific training. • Each evaluator works alone (≈ 1–2 hours). • Interface examined in two passes: first pass focuses on general flow, second on particular elements in detail. 88 CHAPTER 8. USABILITY INSPECTION METHODS Evaluation Name Number of Evaluators Teledata Mantel Savings Transport Total Known Problems 37 77 34 34 52 30 48 34 Average No. Problems Found per Evaluator 51% 38% 26% 20% Table 8.1: The average number of problems found by individual novice evaluators in each of four heuristic evaluations. [Data extracted from Nielsen and Molich [1990, Table 2].] • Notes taken either by evaluator or evaluation manager. • Make list of potential problems and list of positive findings. • Take screen shots (in PNG) as you work - they may not be reproducible later. • Independent findings are then aggregated into one large list (by evaluation manager). This is best done with a spreadsheet. • The large list of potential problems is distributed to each evaluator. • Each evaluator now assigns severity ratings individually to each problem in the large list (unseen by the other evaluators). • The individual severity ratings are averaged to obtain the final severity rating for each problem. • The long list is sorted in decreasing order of average severity. Now you know why a spreadsheet comes in handy. • Group debriefing session to suggest possible redesigns. How Many Problems are Found? Nielsen and Molich [1990] ran four heuristic evaluations using “usability novices” as evaluators. They compared the average number of problems found by each evaluator with the total number of known problems in each system, as shown in Table 8.1. Aggregated Evaluations • Individual evaluators found relatively few problems. • Aggregating the evaluations (merging the problem lists) of several individuals produced much better results. • See Table 8.2 and Figure 8.1. • Group debriefing session to suggest possible redesigns. 8.1. HEURISTIC EVALUATION 89 Aggregate: Teledata Mantel Savings Transport 1 51% 38% 26% 20% 2 71% 52% 41% 33% 3 81% 60% 50% 42% 5 90% 70% 63% 55% 10 97% 83% 78% 71% Table 8.2: The average proportion of usability problems found by various sized aggregates of novice evaluators in each of the four heuristic evaluations. [Data extracted from Nielsen and Molich [1990, Table 4].] Average proportion of usability problems found 100 % 80 % 60 % 40 % 20 % 0% Teledata Mantel Savings Transport 0 5 10 15 20 25 30 Number of evaluators in aggregate Figure 8.1: Average proportion of usability problems found by aggregates of size 1 to 30. [Results from Nielsen and Molich [1990, Figure 4].] 90 CHAPTER 8. USABILITY INSPECTION METHODS Experience of Evaluators The experience of evaluators influences how many problems they find [Nielsen, 1992]. Study of one interface, the Banking System, a touch tone “voice response” telephone banking system, by 3 groups of evaluators: • 31 “novice” evaluators: computer science students with no formal knowledge of UI or usability (no usability expertise). • 19 “regular” specialists: people with UI and usability experience, but no expertise in voiceresponse systems (usability expertise). • 14 “double” specialists: people with expertise both in usability and in telephone-operated interfaces (usability and domain expertise). Task: transfer $1000 from savings account to check account. Sample Banking System Dialogue Figure 8.2 shows the sample dialogue given to evaluators in the study. • This dialogue actually took place! • The problem was that the user did not have authority to make phone transfers. • The results are summarised in Table 8.3. • Aggregating the results of individual evaluators gives the plots shown in Figure 8.3. Conclusions • Single evaluator finds only small subset of potential problems. • Several evaluators should work independently, then aggregate results. • In Nielsen’s study, finding around 80% of usability problems required 2–3 double specialists, 3–5 regular usability specialists, and around 15 novice usability evaluators. • Note that in practice, heuristic evaluations are usually performed by 3–4 usability specialists. • Evaluators pay more attention to major problems without neglecting minor ones. Pros and Cons of Heuristic Evaluation ++ cheap + intuitive + usable early in development process + finds many problems + finds both major and minor problems - may miss domain-specific problems 8.1. HEURISTIC EVALUATION 91 [First there is a short dialogue in which the user is identified by entering an identification number and access code – this is not part of the evaluation exercise] 1) S: Enter one for account information, three for transfers between your own accounts, . . . {the user interrupts the system} 2) U: 3# 3) S: Enter account to transfer from. {savings account number} 4) U: 1234567890# 5) S: Enter account to transfer to. {an abbreviation for the checking account} 6) U: # 7) S: Enter amount in cents. 8) U: 100000# 9) S: From account number twelve thirtyfour fiftysix seventyeight ninety to account number primary account, a transfer of one thousand dollars is to be made. Press one to confirm, zero to cancel. 10) U: 1# 11) S: You do not have access to this function. Figure 8.2: The sample Banking System dialogue used for the study. [Extracted from Nielsen [1992, Figure 1].] Average proportion of usability problems found 100 % 80 % 60 % 40 % 20 % 0% Double Specialists Regular Specialists Novice Evaluators 0 5 10 15 Number of evaluators in aggregate Figure 8.3: Average proportion of usability problems found by aggregates of novice evaluators, regular specialists, and double specialists. [Results from Nielsen [1992, Figure 2].] 92 CHAPTER 8. USABILITY INSPECTION METHODS No. Problem Major Usability Problems 1. Error message appears too late. 2. Do not require dollar amount to be entered in cents. 3. The error message is not precise. 4. The error message is not constructive. 5. Replace term “primary account” with “checking account”. 6. Let users choose account from a menu. 7. Only require a # where it is necessary. 8. Give feedback as name of chosen account. Average for major problems Minor Usability Problems 9. Read menu item description before action number. 10. Avoid gap in menu numbers between 1 and 3. 11. Provide earlier feedback. 12. Replace use of 1 and 0 for accept and reject with # and *. 13. Remove the field label “number” when no number is given. 14. Change prompt “account” to “account number”. 15. Read numbers one digit at a time. 16. Use “press” consistently and avoid “enter”. Average for minor problems Average for all problems Novice Regular Double 68% 68% 55% 6% 10% 16% 3% 6% 29% 84% 74% 63% 11% 47% 32% 32% 26% 46% 100% 79% 64% 21% 43% 43% 71% 64% 61% 3% 42% 42% 6% 10% 6% 6% 0% 15% 22% 11% 42% 63% 21% 32% 37% 47% 32% 36% 41% 71% 79% 71% 43% 36% 36% 79% 57% 59% 60% Table 8.3: Proportion of novice, specialist, and double specialist usability evaluators finding problems in the Banking System. [Results from Nielsen [1992, Table 1].] 8.2. SEVERITY RATINGS 8.2 93 Severity Ratings Severity ratings can help prioritise the fixing of usability problems. • After evaluation sessions, a complete aggregate list of usability problems is given/sent to each evaluator. • Working independently, evaluators assign severity rating [on scale of 0–4] to each problem (≈ 30 mins.). • Severity rating of single evaluator is unreliable, mean of 3–5 evaluators is satisfactory. See the discussion of severity ratings in [Nielsen and Mack, 1994], pages 47–55. Five-Point Severity Scale Score 4 3 2 1 0 Severity catastrophic problem major problem minor problem cosmetic problem only not a problem at all Fix Priority imperative high low Order of Criticality To explicitly take problem frequency into account, assign criticality ratings. Criticality = Severity Ranking + Frequency Ranking Severity 4 catastrophic 3 major 2 minor 1 cosmetic 0 none Frequency 4 >90% 3 51–89% 2 11–50% 1 1–10% 0 <1% 94 CHAPTER 8. USABILITY INSPECTION METHODS 1.3 DATA ENTRY: Text 1.3/1 Adequate Display Capacity Ensure that display capacity, i.e., number of lines and line length, is adequate to support efficient performance of text entry/editing tasks. Example: For text editing where the page format of subsequent printed output is critical, the user’s terminal should be able to display full pages of text in final output form, which might require a display capacity of 50-60 lines or more. Example: For general text editing where a user might need to make large changes in text, i.e., sometimes moving paragraphs and sections, a display capacity of at least 20 lines should be provided. Example: Where text editing will be limited to local changes, i.e., correcting typos and minor rewording, as few as seven lines of text might be displayed. Comment: A single line of displayed text should not be used for text editing. During text editing, a user will need to see some displayed context in order to locate and change various text entries. Displaying only a small portion of text will make a user spend more time moving forward and back in a displayed document to see other parts, will increase load on the user’s memory, and will cause users to make more errors. Reference: Elkerton Williges Pittman Roach 1982 Neal Darnell 1984 See also: 1.3/27 Table 8.4: One of the 944 guidelines by Smith and Mosier. 8.3 Guideline Checking Guidelines . . . specific advice about usability characteristics of an interface. • An evaluator checks an interface against a detailed list of specific guidelines and produces a list of deviations from the guidelines. • Whereas heuristic evaluation employs 10 broad principles, guideline checking often involves dozens (or hundreds) of more specific individual items on a checklist. Example Sets of Guidelines • Sidney Smith and Jane Mosier; Design Guidelines for Designing User Interface Software; The MITRE Corp., 1986. [944 guidelines] ISBN 9992080418 (com, uk) ftp://ftp.cis.ohio-state. edu/pub/hci/Guidelines • C. Marlin Brown; Human-Computer Interface Design Guidelines; Ablex, NJ, 1988. 0893913324 (com, uk) [302 guidelines] ISBN • Deborah Mayhew; Principles and Guidelines in Software User Interface Design; Prentice-Hall, 1991. ISBN 0137219296 (com, uk) [288 guidelines] Table 8.4 shows one of the 944 guidelines from Smith and Mosier. Pros and Cons of Guideline Checking + cheap 8.3. GUIDELINE CHECKING + intuitive + usable early in development process - time-consuming - can be intimidating – often hundreds or thousands of specific guidelines. 95 96 CHAPTER 8. USABILITY INSPECTION METHODS 8.4 Cognitive Walkthrough Task-oriented walkthrough of interface, imagining novice users’ thoughts and actions. Focuses explicitly on learnability. • Design may be mock-up or working prototype. • Analogous to structured walkthrough in software engineering. • Based on cognitive model (CE+) of human exploratory learning. First described in [Lewis et al., 1990], discussion and practical guide in [Wharton et al., 1994]. Other References • Clayton Lewis and John Rieman; Task-Centered User Interface Design: A Practical Introduction; 1993. http://hcibib.org/tcuid/ • John and Packer; Learning and Using the Cognitive WalkthroughMethod: A Case Study Approach; Proc. CHI’95, May 1995. http://www.acm.org/sigchi/chi95/proceedings/papers/ bej1bdy.htm • Rick Spencer; The Streamlined Cognitive Walkthrough Method; Proc. CHI 2000, [Spencer, 2000] Exploratory Learning Rather than read manual or attend course, users often prefer to learn new system by “trial and error” → exploratory learning [Carroll and Rosson, 1987]: 1. Start with rough idea of task to be accomplished. 2. Explore interface and select most appropriate action. 3. Monitor interface reactions. 4. Determine what action to take next. The CE+ Model of Exploratory Learning Based on psychological studies, the CE+ model describes exploratory learning behaviour in terms of 3 components: • Problem-Solving Component User chooses among alternative actions based on similarity between the expected consequences of an action and the current goal. After executing selected action, user evaluates system response and decides whether progress is being made toward the goal. A mismatch results in an undo → “hill-climbing”. • Learning Component When above evaluation process leads to positive decision, the action taken is stored in long-term memory as a rule. 8.4. COGNITIVE WALKTHROUGH 97 • Execution Component User first attempts to fire applicable rule matching current context. If none found, problem-solving component is invoked. Cognitive Walkthrough Preparation a) Identify user population. b) Define suite of representative tasks. c) Describe or implement interface or prototype. d) Specify correct action sequence(s) for each task. Cognitive Walkthrough Steps For each action in solution path, construct credible “success” or “failure” story about why user would or would not select correct action. Critique the story to make sure it is believable, according to four criteria: a) Will the user be trying to achieve the right effect? What is users’ goal – will they want to select this action? b) Will the user know that the correct action is available? Is control (button, menu, switch, triple-click, etc.) for action apparent (visible)? c) Will the user know that the correct action will achieve the desired effect? Once users find control, will they recognise that it is the correct control to produce the desired effect? d) If the correct action is taken, will the user see that things are going ok? After correct action, will users realise progress has been made towards the goal (feedback)? Note that CW always tracks the correct action sequence. Once the user deviates from the correct path their further progress is no longer considered. Group Walkthrough • Performed by mixed team of analysts (designers, engineers, usability specialist). • Capture critical information on three group displays (flip charts, overheads): 1. User knowledge (prior to and after action). 2. Credible success or failure story. 3. Side issues and design changes. • Perhaps also videotape entire walkthrough. 98 CHAPTER 8. USABILITY INSPECTION METHODS Detailed Cognitive Walkthrough Example Forwarding calls on a campus telephone system, from the perspective of a first time user; from [Wharton et al., 1994], pages 118–123. a) Users: New faculty, staff, guests, and visitors. For this evaluation assume that the user is a new university professor. b) Task: Cancel current forwarding and forward calls instead to a colleague with the extension 1234. c) Interface: Standard-size, touch-tone phone on desk. Overlay template includes the following information: FWD *2 CNCL #2 SEND ALL *3 d) Correct Action Sequence: The seven correct actions for accomplishing this task are: 1. Pick up the receiver. Phone: dial tone 2. Press #2. Phone: bip bip bip {command to cancel forwarding} 3. Hang up the receiver. 4. Pick up the receiver. Phone: dial tone 5. Press *2. Phone: dial tone {command to forward calls} 6. Press 1234. Phone: bip bip bip 7. Hang up the receiver. Example Walkthrough Steps 1. Pick up the receiver. Phone: dial tone Success story: Seems ok based on prior experience with phones. 2. Press #2. Phone: bip bip bip Failure story: • Will the user be trying to achieve the right effect? How does the user even know that forwarding is in effect? • Will the user know that the correct action is available? Probably yes, if forwarding is active, one must be able to cancel it. CNCL is visible on the template. 8.4. COGNITIVE WALKTHROUGH 99 • Will the user know that the correct action will achieve the desired effect? Might not recognise CNCL as the control to cancel forwarding. Might think that just pressing ’2’ is sufficient, instead of ’#2’. Might try to press the buttons simultaneously, rather than sequentially. • If the correct action is taken, will the user see that things are going ok? How do first-time users know they have succeeded? After some experience, they will recognise the bips as confirmation, but will they at first? 3. Hang up the receiver. Failure story: • Will the user be trying to achieve the right effect? Big trouble. How do you know you have to hang up before reestablishing forwarding? 4. etc. Pros and Cons of Cognitive Walkthrough ++ finds task-oriented problems + helps define users’ goals and assumptions + usable early in development process - time-consuming - some training required - needs task definition methodology - applies only to ease of learning problems 100 CHAPTER 8. USABILITY INSPECTION METHODS 8.5 Guideline Scoring • The interface is scored according to its conformance against a weighted list of specific guidelines. • A total score is produced, representing the degree to which an interface follows the guidelines. An example checklist for the evaluation of a web site is shown in Figure 8.4. Pros and Cons of Guideline Scoring + cheap + intuitive - must select and weight guidelines - guidelines or weightings often domain-dependent 8.5. GUIDELINE SCORING 101 Web Technologies - Checklist Homepage Design / Usability Homepage (URL) Tester Nr 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 Topic Download time Window title Title tag line Readable URL Error page Meta tags Alt Information Page width Liquid vs. frozen layout Page length Frames Logo placement Logo size Search Search placement Search box colour Search button Width of search box Type of search Navigation Footer navigation links Sitemap link Routing page Splash page Sign-In About the company About link Contact information Privacy policy Name of privacy link Job opening Help Help placement Auto-playing music Animation Graphics/illustration Advertising Body text colour Body text size Body text size frozen Body text typeface Background colour Link colour (unvisited) Link colour (visited) Link colour different Link underlining Date Size Recommended Design Nr. kB Score Strength 50 kB (<10 sec for your customer) Start with Company Name What about Hackable URL Catch errors/dead links, to search For search engines Images, accessibility, Lynx 770 pixel (620-1024) Liquid <2 pages (1000-1600 px) No Upper left 80x68 Pixel Yes, in a box, always Upper part, right or left corner White Call it “Search” or “Go” >=25 characters (30 best) Simple search (Link to advanced) 4 types: left, tabs, top, categories Max. 7 links, single line Name “Site Map” No No “Account” or “Sign In” Always include it Call it “About <company>” Call it “Contact us” If you collect data Call it “Privacy Policy” Call it “Jobs” if you have it If it is a complex site Upper right No No 5-15% <= 3 ads Black 12 points No Sans-serif White Blue Purple Yes (not light grey) Yes (except in navigation bar) Score of URL: Points % You 3 3 3 2 2 3 2 2 2 2 3 3 2 3 3 3 2 2 2 2 1 2 2 3 1 3 2 2 3 2 2 1 2 3 2 1 2 2 1 3 1 2 2 1 3 2 100 Default Recommendation Strong Recommendation Essentail Recommendation from Nielsen, Homepage Usability adapted by alexander@nischelwitzer.com V1.3 Figure 8.4: The Web Usability Checklist. The checklist covers 46 individual guidelines, each with a weighting of between one and three points, for 100 points total. [Adapted from [Nielsen and Tahir, 2001] by Alexander Nischelwitzer, used with permission.] 102 CHAPTER 8. USABILITY INSPECTION METHODS 8.6 Action Analysis Quantitative analysis of actions to predict time skilled user requires to complete tasks, based on time estimates for typical interface actions. Focuses on performance of skilled user (efficiency). Two flavours (levels of detail): a) Formal or “Keystroke-Level” b) Informal or “Back-of-the-Envelope” There are good examples in [Lewis and Rieman, 1993] and [Raskin, 2000]. 8.6.1 Keystroke-Level Analysis Described by [Card et al., 1983]. • Developed from GOMS (Goals, Operators, Methods, Selection) modeling. • Extremely detailed, may often predict task duration to within 20%, but very tedious to carry out. • Used to estimate performance of high-use systems (e.g. telephone operator workstations). Procedure for Keystroke-Level Analysis • Break down tasks hierarchically into subtasks until reach fraction of second level of detail. • Use average values for action times (determined through extensive published research) to predict expected performance for particular task. See Table 8.5. • The analysts do not measure action times themselves, but refer to published tables. Physical Movements Visual Perception Mental Actions Action One keystroke Point with mouse Move hand to mouse or function key Respond to brief light Recognise 6-letter word Move eyes to new location on screen Retrieve one item from long-term memory Learn one step of a procedure Execute a mental step Choose among methods Time 0.28 1.5 0.3 0.1 0.34 0.23 1.2 25 0.075 1.2 Table 8.5: Average Times for typical keystroke-level actions, in seconds. From [Olson and Olson, 1990], and cited by [Lewis and Rieman, 1993]. 8.6. ACTION ANALYSIS 8.6.2 103 Back-of-the-Envelope Action Analysis From [Lewis and Rieman, 1993]. “Back-of-the-Envelope” uses the analogy of sketching out a rough analysis on the back side of an envelope while somewhere away from your desk (“Milchm¨ dchenrecha nung” in German). • List actions required to complete a task (as before), but in much less detail – at level of explaining to a user: “Select Save from the File menu” “Edit the file name” “Confirm by pressing OK” • At this level of analysis, every action takes at least 2 to 3 seconds (videotape a few users doing random tasks if you do not believe it takes this long!). • Allows quick estimation of expected performance of interface for particular task. Pros and Cons of Action Analysis + predicts efficiency of interface before building it - time-consuming - some training required 104 CHAPTER 8. USABILITY INSPECTION METHODS Chapter 9 Usability Testing Methods “ Would you fly in an airplane that hasn’t been flight tested? Of course not. So you shouldn’t be using software that hasn’t been usability tested. ” [ Ben Shneiderman, The Front Desk, BBC Video, 1995. ] Empirical testing of interface design with representative users. • Thinking Aloud: Test users verbalise thoughts while performing test tasks. • Co-Discovery: Two test users explore an interface together. Insight is gained from their conversation while performing test tasks. • Formal Experiment: Controlled experiment, face-to-face with test users, measurements and statistical analysis. • A/B Test: Controlled experiment on (part of) actual user population, typically (remote) web site users, with measurements and statistical analysis. • Query Techniques: Interviews and questionnaires. • Usage Studies: Usage data is collected from a small number of users working on their own tasks in their natural environment over a longer period. References + Jeffrey Rubin and Dana Chisnell; Handbook of Usability Testing; 2nd Edition, Wiley, 2008. ISBN 0470185481 (com, uk) [Rubin and Chisnell, 2008] + Joseph Dumas and Janice Redish; A Practical Guide to Usability Testing, Revised Edition; Intellect, 1999. ISBN 1841500208 (com, uk) [Dumas and Redish, 1999] • Thomas Landauer; Research Methods in HCI ; In Handbook of HCI, Helander (Ed.), NorthHolland, 1988. [Landauer, 1988] • Ericsson and Simon; Protocol Analysis: Verbal Reports As Data; MIT Press, May 1993. ISBN 0262550237 (com, uk) [Ericsson and Simon, 1993] • van Someren, Barnard, and Sandberg; The Think Aloud Method; Academic Press, 1994. ISBN 0127142703 (com, uk) [van Someren et al., 1994] 105 106 CHAPTER 9. USABILITY TESTING METHODS ++ Andy Field; Discovering Statistics Using SPSS; Sage Publications, Second Edition, 2005. ISBN 0761944524 (com, uk) [Field, 2005] + Andy Field and Graham Hole; How to Design and Report Experiments; Sage Publications, 2002. ISBN 0761973834 (com, uk) [Field and Hole, 2002] • Shaughnessy et al; Research Methods In Psychology; 6th Edition, McGraw Hill, April 2003. ISBN 0071198903 (com, uk) [Shaughnessy et al., 2003] Online Resources • K. Anders Ericsson; Protocol Analysis and Verbal Reports on Thinking http://www.psy.fsu. edu/faculty/ericsson/ericsson.proto.thnk.html Why do Usability Testing? • People believe they understand behaviour of others based on their own experiences. • This belief only lost through prediction then measurement (→ usability tests). • Experience changes one’s perception of the world. • It is almost impossible to “forget” an experience and put oneself in position of someone not having had the same experience. • Designers of system find it very easy to use. • More often than not, intuitions are wrong! Keyboard vs Mouse From studies at Apple [Tognazzini, 1992]: • Test users consistently report that keyboarding is faster than mousing. • The stopwatch consistently proves that mousing is faster than keyboarding, an average of 50% faster. “In one study of this phenomenon (Tognazzini, Tog on Interface, 1992.), users were asked to do the same task using the keyboard and the mouse. The keyboard was powerfully engaging, in the manner of many videogames, requiring the user to make many small decisions. The mouse version of the task was far less engaging, requiring no decisions and only low-level cognitive engagement. Each and every user was able to perform the task using the mouse significantly faster, an average of 50% faster. Interestingly, each and every user reported that they did the task much faster using the keyboard, exactly contrary to the objective evidence of the stopwatch. The most obvious take-away message from this is that people’s subjective beliefs as to what is or is not quick are highly-suspect. No matter how heart-felt the belief, until a stopwatch shows it is true, do not accept personal opinion about speed and efficiency as fact. Instead, user-test.” [Tognazzini, 1999] 9.1. PREPARING FOR USABILITY TESTING 107 Observers Facilitator Participant Table Figure 9.1: A simple usability test setup. This and the following test setup diagrams were inspired by those in [Rubin, 1994]. 9.1 Preparing for Usability Testing Test Environment Ensure comfortable test environment: • Organise quiet room. • Put up sign “User test in progress – Do not disturb”. • Disable telephones (fixed line and mobile). • Ensure adequate lighting. • Provide (non-alcoholic) refreshments. Or use dedicated usability lab . . . Test Equipment • Digital video camera (MiniDV, SD, DVD). • Video tripod. • Good microphone (table, lapel, or headset). A singer’s microphone is no good, because it must be held right next to the mouth. • Headphones (to monitor sound). 108 CHAPTER 9. USABILITY TESTING METHODS Mirror Microphone Observers Facilitator Participant Video Camera Table Figure 9.2: A typical single room, single camera usability test setup. Figure 9.3: A simple usability test with a single video camera. A mirror is used to capture the user’s facial expressions. 9.1. PREPARING FOR USABILITY TESTING 109 Facilitator Participant Microphone Video Camera Observers Table Figure 9.4: Single room test setup. Facilitator sits behind test participant monitoring video output and using logging software. Computer Monitor Video Monitors Video Camera Participant Facilitator Observers Table Figure 9.5: Observation room with electronic monitoring. 110 CHAPTER 9. USABILITY TESTING METHODS Intercom Speaker VCR Participant One-Way Mirror Video Camera Facilitator Computer Monitor Observers Video Monitors Table Figure 9.6: A classical usability lab, including an observation room with a one-way mirror. VCR Additional Observers User Observers Sliding Glass Doors Facilitator Table Video Monitors Figure 9.7: The standard usability lab at Microsoft headquarters in Seattle. There 25 such labs on two floors, side to side. Users enter from the right, developers enter from the left. [Adapted from diagram at [Microsoft, 2005].] 9.1. PREPARING FOR USABILITY TESTING 111 Morae Recorder Webcam Observers Facilitator Participant Video Camera Table Figure 9.8: Morae software [TechSmith, 2008] installed on the test computer will capture the screen in one stream and the web cam of the user’s face in a second, synchronised stream. • Mirror (to capture user’s facial expressions). • Light (desk lamp or video lighting). • Colour video monitor (to view camera image). • DVD recorder. • Video cart. • Powerstrip, extension cables. • “Do not disturb” sign. • Refreshments. • Logging software or forms. Figures 9.9 and 9.10 show the portable usability kits used at Graz University of Technology. Roles in the Test Team • Test Facilitator (Administrator, Moderator, Manager, Monitor) In overall charge of test, responsible for all interaction with test user (introduction, test, debriefing). • Data Logger (Scribe) 112 CHAPTER 9. USABILITY TESTING METHODS Usability Kit Inventory List 1. 2. 3. 4. Tripod Hama Profil 74 Rucksack LowePro Headphones Headphones extension cable 2 5. Microphone Philips SBC ME570 6. Microphone extension cable 7. Headphone adapter 8. Usability kit inventory list 9. Video camera manual 10. Video camera power supply 11. 12. 13. 14. 15. 16. Video camera mains cable Microphone adapter cable Video camera Sanyo Xacti HD1010 Video camera bag Video camera remote control Transcend SD HC Card 16gb 3 5 4 1 6 7 10 11 8 14 12 13 9 15 16 Figure 9.9: The portable usability kit used at Graz University of Technology. The inventory shows all of the components of the kit. Setting up. Packing. Figure 9.10: The portable usability kit used at Graz University of Technology. On the left the kit has been set up ready for use. The righthand photos illustrate packing the kit. 9.2. SIX STAGES OF CONDUCTING A TEST 113 Records activities and events of interest on paper, incl. time of occurrence. [Assign shorthand codes to expected activities before test.] • Video Operator Responsible for recording entire test proceedings, incl. initial instructions and debriefing: – Check camera angles so user and interface both clearly visible. – Use manual focus (can’t autofocus on computer screen). – Turn off any data fields (time, date, etc.) in the camera. – Ensure audio recording level is high enough. – Label, copy, and edit tapes. • Computer Operator – Play the role of computer in a paper prototype. – Reset the interface to a clean state for each new test user (clear the cache, history, cookies, etc.). – Do not set the Home button to a web site under test, ask the user to type the URL. – Restart after system crash, unexpected hang-ups, etc. Test Users • Test Participants or Test Users – Users taking part in the test. – Never ever call them test subjects! 9.2 Six Stages of Conducting a Test 1) Develop the Test Plan 2) Select and Acquire Participants 3) Prepare Test Materials 4) Run a Pilot Test 5) Conduct the Real Test 6) Analysis and Final Report Note: Always do a pilot test! 114 CHAPTER 9. USABILITY TESTING METHODS 9.2.1 The Test Plan Main section headings: • Purpose • Problem Statement • User Profile • Method (Test Design) • Task List • Test Environment • Data to be Collected • Content of Report Task List • Prioritise tasks by frequency and criticality. • Choose those most frequent and critical to test. • Make a task list for test team internal use only. • For each task: – Define any prerequisites. – Define successful completion criteria. – Specify maximum time to complete each task, after which help may be given. – Define what constitutes an error. • Do not instruct the test user to return to the initial screen (home page) at the beginning of each task. If they do so of their own accord, that fine. See Figure 9.11. 9.2.2 Selecting and Acquiring Participants • Users are typically divided into different user groups, based on their characteristics and needs. • Test each user group separately. • Test at least 5 test users per user group. • Choose representative test users who span the chosen user group. • Acquire test users via employment agency, students, existing customers, internal personnel. • Maintain a database of potential test users. • Screening questionnaire (ensure users fit profile). 9.2. SIX STAGES OF CONDUCTING A TEST Task 1 Description Open the 3D landscape from with Harmony. 2 Find and open text document “Welcome to IICM”. 3 Navigate to City of Graz collection. 4 115 Criteria PreReq: Harmony Session Manager up and displayed. Completed: Landscape window open. MaxTime: 1 minute. PreReq: Landscape window open at root collection. Completed: Text displayed in Text Viewer. MaxTime: 1 minute. PreReq: Landscape window open. Completed: City of Graz collection in centre of view and opened. MaxTime: 2 minutes. etc. . . . Figure 9.11: An example internal task list for a usabilty test of Harmony. 9.2.3 Test Materials • Orientation Script • Background Questionnaire • Nondisclosure and Consent Form • Training Script (if any) • Task Scenarios • Data Collection Forms • Debriefing Topic Guide • Post Test Questionnaire • Checklist Orientation Script • Introduce yourself and any observers by first name (no titles or job descriptions!). • Explain that the purpose of the test is to collect input to help produce a better interface. • Emphasise that system is being tested not user. • Acknowledge software is new and may have problems. • Do not mention any association you have with product (do mention if you are not associated with product). • Explain any recording (reassure confidentiality). • Say user may stop at any time. • Say user may ask questions at any time, but they may not be answered until after the test is completed. 116 CHAPTER 9. USABILITY TESTING METHODS “Hi, my name is Keith. I’ll be working with you in today’s session. [Frank and Thomas here will be observing]. We’re here to test a new product, the Harmony 3D Information Landscape, and we’d like your help. I will ask you to perform some typical tasks with the system. Do your best, but don’t be overly concerned with results – the system is being tested, and not your performance. Since the system is a prototype, there are certainly numerous rough edges and bugs and things may not work exactly as you expect. [I am an independent researcher hired to conduct this study, and have no affiliation with the system whatsoever]. My only role here today is to discover the flaws and advantages of this new system from your perspective. Don’t act or say things based on what you think I might want to see or hear, I need to know what you really think. Please do ask questions at any time, but I may only answer them at the end of the session. While you are working, I will be taking some notes and timings. We will also be videotaping the session for the benefit of people who couldn’t be here today. If you feel uncomfortable, you may stop the test at any time. Do you have any questions? If not, then let’s begin by filling out a short background questionnaire and having you sign the nondisclosure agreement and consent to tape form.” Figure 9.12: An orientation script for testing the Harmony 3D Information Landscape. • Invite questions. See Figure 9.12. Background Questionnaire • Admin. data: date, test number, user number or id. • General data: age (range), sex, educational level, . . . • Computer experience: total time, frequency of use, types of software, have used a GUI before, . . . • Application experience: total time, frequency of use, brand. So that you can better understand the user’s performance during the test. See Figure 9.13. The facilitator should fill in the background questionnaire, asking the test user the questions. If possible, copy and give to observers before the test proper starts. Training Script Exact written description of prior training: • Demonstration of GUI. • Demonstration of special interaction styles: mouse keys, drag-and-drop, etc. • Walk-through of sample task. • Demo of how to think aloud (for Thinking Aloud style tests). 9.2. SIX STAGES OF CONDUCTING A TEST 117 Background Questionnaire Date: Test No.: User No.: General Information Age: Sex: Education 1. Please circle the highest educational grade you have achieved: Secondary School 2. University Degree Doctorate If you are a student or graduate, please state your major area of study. Computer Experience 1. How long have you been using personal computers (years and months)? 2. In a typical week, how many hours do you use a computer? 3. Please circle the types of system you have used, followed by approximately how many months experience you have with them. Months of Experience Operating System DOS OS/2 Windows Unix Mac Application Word Processor Database Speadsheet CAD/CAM Experience of Related Systems 1. How many hours per week do you spend accessing the Internet/World Wide Web? 2. Do you have experience as a Web administrator or webmaster? If so, how many months? 3. Have you used systems involving navigation through 3D worlds? If so, which systems? Figure 9.13: A background questionnaire for the Harmony 3D Information Landscape usability test. 118 CHAPTER 9. USABILITY TESTING METHODS Thank you for participating in our product research. Please be aware that confidential information will be disclosed to you and that it is imperative that you do not reveal information that you may learn during the course of your participation. In addition, your session will be videotaped, to allow staff members who are not present to observe your session and benefit from your feedback. Please read the statements below and sign where indicated. Thank you. I agree that I will disclose no information about the product research conducted by ABC Company Inc. or about the specifications, drawings, models, or operations of any machine, devices, or systems encountered. I understand that video and audio recordings will be made of my session. I grant ABC Company Inc. permission to use these recordings for the purposes mentioned above, and waive my right to review or inspect the recordings prior to their dissemination and distribution. Please print name: Signature: Date: Figure 9.14: A combined nondisclosure and consent form. Task Scenarios The task descriptions given to the test users. • Simple introductory first task (early success). • Realistic scenarios in typical order. • If sequential ordering not crucial, randomise presentation order (→ counterbalances learning effect). • Each task scenario on a separate sheet. [do not hand the user all the tasks at once, but one at a time!] • Do not guide participants through the task! [Describe the goal rather than individual steps] An Example Task Scenario Task 3. Using the 3D landscape, navigate to the collection about the city of Graz and open it. Data Collection Forms • Define abbreviations for expected events → coding scheme. See Table 9.1. ? • Use a probe mark like ○ to signal an event worth probing during debriefing. • Paper or electronic data collection forms (or instrumented software). See Figure 9.15. 9.2. SIX STAGES OF CONDUCTING A TEST Code S E O G Q X H P T ? ○ C * 119 Event Start of task. End of task. Observation (problem). Positive impression. Verbatim user comment. Error or unexpected action. User given help by facilitator. Prompted by test facilitator. Timeout, exceeded maximum time. Probe this activity during debriefing. Comment by facilitator. Very important action. Table 9.1: A simple coding scheme for logging events during a test. Test: Date: Task Time: Elapsed Time User No.: Page: of Observations Figure 9.15: A generic data collection form. Test: Edit HTML Document Date: 23 Apr 97 Time: 11:50 Task Elapsed Time 1 04:25 2 06:00 07:00 11:30 15:20 16:15 User No.: 3 Page: 1 of 3 Observations X Opened wrong file. Found mistake. X Opened wrong file again. Self-corrected due to error message. P T Q “I wish it were always that easy!” ? ○ Very long hesitation, then correct action. E Figure 9.16: A completed data collection form with a probe mark during task 2. 120 CHAPTER 9. USABILITY TESTING METHODS Debriefing Guide • Things to discuss with user in any case. • Structured interview. Post Test Questionnaire Collect feelings, opinions, suggestions (hard to observe in other ways), for example: • Interface organisation matches real-world tasks? • Too much or too little information on screens? • Similar information consistently placed? • Problems with navigation? • Computer jargon? • Appropriate use of colour? Checklist • Make chronological checklist of things to do, as shown in Figure 9.17. 9.2.4 Pilot Test Always perform pilot tests of the entire test procedure. You always find something you need to fix, such as: • ambiguous instructions. • unrealistic time estimates. • ambiguous task completion criteria. • misleading questionnaire questions. • dead battery in microphone. • blank DVDs incompatible with DVD recorder. If you do not catch these things in a pilot test and one of these problems occurs with user number 1 of 10 scheduled at hourly intervals, it can ruin the whole test. Maybe even run two pilot tests: once with colleagues, once with one or two real test users. 9.2. SIX STAGES OF CONDUCTING A TEST 121 Test Checklist Scan your customised checklist. Everything ready in test room. Prepare yourself mentally. Establish protocol for observers. Greet the participant. Read the orientation script and set the stage. Have participant sign consent forms. Administer background questionnaire. Move to testing area. Provide any prior training. Provide demo of thinking aloud. Record start time. Distribute or read written task scenarios to participant one at a time. Observe, note interesting and critical events. Debriefing interview. Administer post test questionnaire. Thank participant, provide any remuneration, show participant out. Organise data sheets and notes. Make screenshots or problems and positives. Summarise thoughts about test. Prepare for next participant. Figure 9.17: A test checklist. 9.2.5 Conducting the Real Test • Test facilitator handles all interaction with participant (other team members and observers remain completely quiet). • Do not prompt or bias user during test (beware of non-verbal signals). • Only assist if user in severe difficulty (make note of when and what help given). • Conduct debriefing interview or questionnaire. • Save screen shots (in PNG) of any interesting problems and positive findings right after the test. They may not be reproducible again later. • If you use screen capture software, you can extract stills from the screen video later on. Extract stills as PNG or another lossless format such as BMP (and then convert to PNG). Do not extract a still image as JPEG, since that will introduce artefacts into the image. Debriefing Interview 1. Let user speak thoughts first: “So, how was it?”. 2. Let them talk and talk, until they stop talking of their own accord. 3. Top-down: probe high-level issues from topic guide first, then more detailed questions about each task. 122 CHAPTER 9. USABILITY TESTING METHODS ? 4. Probe specific issues arising from test notes ○ . See Figue 9.16. 5. Ask any questions passed to the facilitator from the observers (they should be written onto index cards by the observers). See also Section 9.7.1. 9.2.6 Analysis and Final Report • Compile and summarise data, for example: – Mean, median, range, and standard deviation of completion times. – Percentage of users performing successfully. – Bar chart of preference scores. – etc. • Analyse data: – Identify errors and difficulties which arose. – Diagnose the source of each error. – Prioritise problems by their severity or criticality. Final Report • Title Page • Description of Test Environment – Hardware, software version, test room, dates when tests were performed. • Executive Summary – Concise summary of major findings, no more than a few pages. • Description of Test – Updated test plan, method, training, and tasks. • Test Person Data – Tabular summary of age, occupation, experience. • Results – Tabular and graphical summaries of times taken, number of errors made, questionnaire responses, etc. – Discussion and analysis, amusing quotations. • List of Positive Findings • List of Recommendations List of problems discovered, in descending order of severity, and recommended improvements. For each recommendation: – diagnose why the problem occurred 9.2. SIX STAGES OF CONDUCTING A TEST 123 – illustrate it with a screen shot – rate its severity (0. . . 4 scale) – indicate exactly how many test users experienced the problem – include a reference to timestamp(s) on the video tape – possibly include an appropriate user quotation – describe your suggested improvements • Appendices (raw data and tables). – Background questionnaires, consent forms, orientation script, data collection forms, video and audio tapes, transcripts, etc. Example Recommendation R12. Sort Order Panel (Severity 3.2) • Problem: Users had problems understanding the sort order panel. In particular, the plus and minus icons used for increasing and decreasing order are non-intuitive. • Reference: TP1, 00:08:15 “What does this plus mean?” • Recommendation: redesign the icons, for example as sloping ramps. 124 CHAPTER 9. USABILITY TESTING METHODS 9.3 Thinking Aloud Test users are asked to verbalise their thoughts (“think aloud”) while performing tasks. • provides wealth of process data • relatively small number of test users (say 3 to 5) • many vivid and colourful quotes. Detecting Vocabulary Problems with Thinking Aloud Example from Lewis and Rieman [1993, Section 5.5]: • Menu-based administrative system for law offices. • System messages extensively refered to “parameter”. • Test users persistently misread “parameter” as “perimeter”. • Hard to detect such problems just by watching people’s mistakes, much easier when they are thinking aloud. The Thinking Aloud Method Ask users to tell you: • what they are trying to do • things they read • questions that arise in their mind • things they find confusing • decisions they make Preparing the User • Demonstrate thinking aloud for an unrelated task, e.g. looking up the films on tonight in the local cinemas (newspaper or online). • Show user short video clip of a previous thinking aloud test. • Have the user practice the technique using a different interface and unrelated task. • Request questions be asked as they arise, but explain that you won’t answer them until after the test. 9.3. THINKING ALOUD 125 Test Facilitator’s Role • Spontaneous comments from the user are best. • If the user stops talking aloud, encourage them to keep up the flowing commentary with neutral, unbiased prompts: – non-committal “uh huh” – “Can you say more?” – “Please tell us what you are doing now?” – “I can’t hear what you are saying” – “What are you thinking right now?” • Do not direct the user with specific questions like: – “Why did you do that?” – “Why didn’t you click here?” – “What are you trying to decide between?” Do Not Ask Why Questions • Maier [1931]. Problem: tie together two strings hanging from ceiling, too far apart to be grabbed. Solution: tie weight to one string, set it swinging, grab other string, wait for swinging string to come within reach. When Maier “accidentally” brushed against one string, people much more likely to find solution. When asked how arrived at solution, did not say Maier’s brushing against string had given them idea. • Nisbett and Wilson [1977]. In market survey, most people preferred rightmost pair of three identical pairs of underwear. When asked why, people made up plausible (but wrong) reasons. Real reason is natural bias towards last of number of closely matched alternatives. Specific “why” questions encourage plausible, but often unreliable, answers. Listening Labs Pre-defined tasks often neglect what individual users want to accomplish and sometimes miss larger strategic findings. • Single user, thinking aloud. • Environment simulates real-use setting. • No preset tasks, but instead users set their own context and tasks. • See [Hurst and Terry, 2000]. 126 CHAPTER 9. USABILITY TESTING METHODS Pros and Cons of Thinking Aloud ++ finds many usability problems ++ finds why they occur (process data) + small number of test users (3 to 5) + usable early in development process + requires little facilitator expertise + generates colourful quotes - - thinking aloud slows users down by about 17% [Ericsson and Simon, 1993, page 105] - depending on the instructions given to the user, having to think aloud can change the user’s problem-solving behaviour (they might think more before acting). - cannot provide performance data (bottom-line data) 9.4 Co-Discovery • Two test users explore an interface together. • There is natural interaction and communication between the participants. ++ No unnatural thinking aloud. - Need twice as many test users. - - Validity issue: would the interface be used by two people working together in real life? 9.5. FORMAL EXPERIMENTS 9.5 127 Formal Experiments Controlled experiments with test users. • More or less rigorous statistical analysis. • Summative evaluation – objective measurement of performance of (fully) implemented design. • Two main uses: – testing the absolute performance of an interface. – objectively comparing two (or more) alternative interface designs. Formal experiments provide bottom-line data (performance measurements), but require larger number of test users for statistical accuracy (sometimes around 16 to 20, but often 50 or 100 or more). Performance Measurement Collect objective, quantitative data, e.g.: • Time to complete specific task(s). • Number of tasks completed within given time. • Number of errors. • Number of deviations (extra clicks) from optimal path. • Accuracy (answer to question true or false). • Ratio successful interactions : errors. • Time spent recovering from errors. • Number of commands/features used. • Number of features user can remember after test. • How often help system used. • Time spent using help. • Ratio positive : negative user comments. • Number of times user sidetracked from real task. Validity Validity: is measured data relevant to the usability of the real system in real world conditions? Typical validity problems include: • Testing with the wrong kind of user For example, testing business students instead of managers for a management information system. However, testing business students will generally lead to better results than testing, say, mathematics students. 128 CHAPTER 9. USABILITY TESTING METHODS • Testing the wrong tasks The results from testing a toy task in a prototype of a few dozen hypermedia documents may not be relevant to a planned system for managing tens of thousands of documents. • Not including time constraints and social influences Queues of people waiting in line, noise levels in the working environment, etc. 9.5.1 Testing Absolute Performance of One Interface • One interface. • Run an experiment to objectively determine whether the interface satisfies specific requirements. • For example: measure how long it takes 20 expert users to perform task X. • Result: an expert user can on average perform task X in 2 minutes 10 seconds ± 6 seconds. 9.5.2 Comparing Two Alternative Interfaces • Two interfaces, A and B. • Run an experiment to objectively determine which interface is better, according to some criterion (efficiency, error rate, etc.). • Two different ways of designing an experiment: independent measures (also called betweengroups or unrelated) and repeated measures (also called within-groups or related). Between-Groups Experiment • Two equally-sized groups of test users. • Randomly assign users to two groups. • Identical tasks for both groups. • Group 1 uses only system A, group 2 only system B. + no problems with learning effect. - cannot ask users which they preferred. - generally needs twice as many users. - large individual variation in user skills (std. dev. ≈ 50%). Repeated Measures (or Within-Groups) Experiment • One group of test users. • Randomly assign users to two equally-sized pools. • Users perform equivalent tasks on both systems. • Pool 1 uses system A first, pool 2 system B first. 9.5. FORMAL EXPERIMENTS 129 + automatically controls for individual variability. + can ask users which they preferred. + generally needs fewer test users in total. - transfer of skill between systems (learning effect). Example Experimental Designs Between-Groups System A System B John Dave James Mariel Mary Ann Stuart Phil Keith Tony Gary Gordon Jeff Ted Bill Edward ... ... Charles Thomas Celine Doug Within-Groups (Repeated Measures) Participant Sequence Elisabeth A, B Sven A, B Amanda A, B Claudia A, B Terry A, B Nigel A, B Barry A, B ... ... Ben B, A Michael B, A Richard B, A Statistical Analysis • Is there a statistically significant difference between system A and B? • How large is the difference? • How accurate are the results? [hypothesis testing] [point estimation, averages] [standard deviation, confidence intervals] We are 95% certain that the time to perform task X is 4.5 ± 0.2 minutes. System A is faster than system B at the level p < 0.2. [20% chance that B is faster, but still choose A since odds are 4:1] Sample Size (How Many Test Users?) • Depends on desired confidence level and confidence interval. • Confidence level of 95% often used for research, 80% ok for practical development. • Nielsen: survey of 36 published usability studies [Nielsen, 1993b, pages 166–169]. Rule of thumb: 16-20 test users. • If the differences are small, you might need 50 or 100 or more users to detect a statistically significant difference. 130 CHAPTER 9. USABILITY TESTING METHODS Case Study: Touchscreen Toggle Design Catherine Plaisant, University of Maryland [Plaisant and Wallace, 1992]. • Home automation system with touchscreen display. • Toggles (on/off switches) for lighting, climate control, security, etc. • Six toggle designs: 1-Button, Rocker, 2-Button, Words, Slider, and Lever. • Usability study with 15 novice users. Pros and Cons of Formal Experiment ++ collects objective, quantitative data (bottom-line data) ++ allows comparison of alternative designs - - needs significant number of test users (20 or more) - usable only later in development process - requires facilitator expertise - cannot provide why-information (process data) 9.6. A/B TESTING 9.6 131 A/B Testing Controlled experiments on a web site with its real live users. • A proportion of visitors are randomly assigned to a variant (B) of the web site (they have a slightly different experience), the others see the standard web site (A, the control). • A cookie is usually assigned, so that individual users always see the same variant. • A metric (the overall evaluation criteria, or OEC) such as click-through rate is measured for each variant. • The differences in OEC are examined for statistical significance. • Originally used in marketing [Hopkins, 1923], where direct mail with variants of brochures elicited varying response rates (go with the best one). • Online A/B testing was pioneered at Amazon.com. • Also called split testing, bucket testing, and multivariant testing. References ++ Ron Kohavi et al; Controlled Experiments on the Web: Survey and Practical Guide; Data Mining and Knowledge Discovery, Vol. 18, No. 1, Kluwer, Feb 2009, pages 140–181. doi:10.1007/ s10618-008-0114-1 [Kohavi et al., 2009] ++ Bryan Eisenberg and John Quarto-vonTivadar; Always Be Testing: The Complete Guide to Google Website Optimizer; Sybex, Aug 2008. ISBN 0470290633 (com, uk) [Eisenberg and QuartovonTivadar, 2008] + Thomas Crook et al; Seven Pitfalls to Avoid when Running Controlled Experiments on the Web; Proc. KDD 2009, Paris, France, Jun 2009, pages 1105–1114. doi:10.1145/1557019.1557139 [Crook et al., 2009] ++ Ron Kohavi and Roger Longbotham; Online Experiments: Lessons Learned; IEEE Computer, Vol. 40, No. 9, Sept 2007, pages 103–105. doi:10.1109/MC.2007.328 [Kohavi and Longbotham, 2007] + Ron Kohavi et al; Practical Guide to Controlled Experiments on the web: Listen to Your Customers not to the HiPPO; Proc. KDD 2007, San Jose, California, Aug 2007, pages 959–967. doi:10. 1145/1281192.1281295 [Kohavi et al., 2007] • Claude Hopkins; Scientific Advertising; Lord & Thomas, 1923. Copyright expired. Freely available in PDF. [Hopkins, 1923] Online Resources ++ Ron Kohavi; Practical Guide to Controlled Experiments on the Web: Listen to Your Customers not to the HiPPO; Industry Day talk at CIKM 2008 (Duration 23:55). Video. http: //videolectures.net/cikm08_kohavi_pgtce/ + Wikipedia; A/B testing; http://en.wikipedia.org/wiki/A/B_testing + Anne Holland; Which Test Won?; http://whichtestwon.com/ 132 CHAPTER 9. USABILITY TESTING METHODS • Bryan Eisenberg; A/B Testing for the Mathematically Disinclined; ClickZ, 07 May 2004 http: //www.clickz.com/3349901 Running an A/B Test • Problems and biases in the design can be detected by running an A/A test. • Multiple variants can be tested simultaneously (sometimes called A/B/N or A/B/Z tests). • The user base must be large enough, so that there is a reasonable chance of reaching statistical significance. • The test users are normal visitors to the site and usually unknowingly take part in an A/B test. Examples of A/B Testing • Google tested 41 shades of blue to find the best colour for links [Holson, 2009; Mayer, 2009]. • The BBC uses A/B testing for different design elements on its web sites. • Microsoft runs many A/B tests on its web sites. • Amazon has run many experiments to optimise its shopping cart. • Amazon even experimented with different prices for the same product. 9.7. QUERY TECHNIQUES 9.7 133 Query Techniques Ask test users questions after having used system to perform representative tasks: • Interview • Questionnaire Provide subjective data about users’ view of system: preferences, impressions, attitudes. Simple, cheap, and useful supplement to thinking aloud or formal experiment. 9.7.1 Interview • Let user speak thoughts first: “So, how was it?”. • Top-down: probe high-level issues from topic guide first, then more detailed questions about each task. • Probe specific issues arising from test notes. • Review answers to post test questionnaire. • Accept questions from any observers (should be written on a slip of paper for the facilitator to ask). ++ flexible – facilitator can probe interesting issues - more time-consuming - harder to analyse and compare 9.7.2 Questionnaire • Written, structured form filled out by user. • Quantitative and qualitative data. • Electronic questionnaires such as WAMMI [WAMMI, 2000] or the GVU Web User Survey [GVU, 1998]. • Note, however, that designing truly unbiased questionnaires and surveys is a discipline of its own [Foddy, 1994; Dillman, 1999]. ++ can reach wide subject group (by post, email, Web forms) ++ easy to analyse and compare + less time-consuming than interview + easy to repeat (trends) - less flexible than interview 134 CHAPTER 9. USABILITY TESTING METHODS Styles of Question 1. General: age (range), sex, occupation, etc. 2. Open-Ended: suggestions, comments. I found the following aspects particularly easy to use (please list 0–3 aspects): ______________________________________ ______________________________________ ______________________________________ 3. Likert Scale: judge agreement with specific statement (5, 6, or 7 point scale best). Overall, I found the widget easy to use. Strongly Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree 5 and 7 point scales offer the user a midpoint (a fence to sit on). Use a 6 point scale to force users to jump one way or the other. More than 7 point scales provide too little distinction between neighbouring points. 4. Semantic Differentials: sliding scale between opposing pairs of adjectives (5 or 7 point scale best). Circle the number most closely matching your feelings about the interface. Simple Professional Reliable Attractive 3 3 3 3 2 2 2 2 1 1 1 1 0 0 0 0 1 1 1 1 2 2 2 2 3 3 3 3 Complex Unprofessional Unreliable Unattractive Externally, on the questionnaire, the user sees unbiased ratings from 3 down to 0 and back up to 3. Internally, for statistical analysis, you convert these ratings to scores between 0 points (the worst rating) and 6 points (the best rating). 5. Overall Preference: A vote for one item from a set of choices. Overall, which hierarchy browser did you prefer? Tree View (Windows explorer) Hyperbolic browser Treemap Information pyramids 6. Multi-Choice: boxes to tick. [Tick just one box, tick multiple boxes, yes and no boxes] Which methods do you use to get help (tick any that apply)? Context-sensitive help On-line manual Printed manual Google search Ask a colleague 9.7. QUERY TECHNIQUES 7. Ranked: place items in order. Please rank the usefulness of these methods (1 most useful, 2 next, 0 if unused)? Menu-selection Button Accelerator Key Command line Pros and Cons of Query Techniques + collect subjective user view of system + both quantitative and qualitative data + useful supplementary information + simple + cheap - subjective data often unreliable 135 136 CHAPTER 9. USABILITY TESTING METHODS 9.8 Usage Studies Users actual activity is estimated or recorded and then analysed. Purpose of a Usage Study • Insight into how long users spend on each activity. • Insight into which software is used for what purpose. • Insight into which features of software packages are most used or unused. 9.8.1 Diary Studies • Users are asked to keep a diary (or logbook) of their usage of a system over several days or weeks (self-reporting). • Repeat for several users. • The diary entries are converted into estimates of the amount of time spent on various activities. • Statistically analyse the resulting data. Pros and Cons of Diary Studies + anecdotal evidence (better than nothing?) - subjective estimates made by users – self-reporting is highly unreliable 9.8.2 Software Logging • An instrumented version of the software logs all user interactions. • Users must give their informed consent. • Can recruit a larger sample of test users (20–50+). • Gather and aggregate the various log files. • Statistically analyse the resulting data. Pros and Cons of Software Logging + objective log file data - all the software of interest must be instrumented - hard (impossible) to infer the user’s intentions and motivations 9.8. USAGE STUDIES 9.8.3 137 Observational Studies • Record one or more typical days of use of a system (screen capture and user video). • Users must give their informed consent. • Repeat for several users. • Manually analyse the recordings and encode the activities (begin and end) in a timeline. • Statistically analyse the resulting data. References • Byrne et al; A Day in the Life of Ten WWW Users; unpublished paper, 2000. [Byrne et al., 2000] • Byrne et al; The Tangled Web We Wove: A Taskonomy of WWW Use; [Byrne et al., 1999] Finding Willing Users Users are often reluctant to participate in a usage study, because they feel it is an invasion of their privacy. Over several meetings and many hours, explain to potential test users: • Exactly what will be recorded. • That they can turn off the recording at any time. • Exactly how the data will be analysed. • That statistics will be aggregated on activities and software usage over several users. • That statistics of individual user performance will not be aggregated. • That individual users will not be identifiable in any reports or publications. • That you will seek specific permission before showing or publishing and video, photographs, or screenshots. Pros and Cons of Observational Studies ++ objective analysis of usage (not self-reporting) - often difficult to find willing users – video analysis is extremely time-consuming 138 CHAPTER 9. USABILITY TESTING METHODS Chapter 10 Usability in Practice References • Michael Wiklund (Ed.); Usability in Practice; Academic Press, 1994. ISBN 0127512500 (com, uk) [Wiklund, 1994] [Out of print] • ACM Interactions, Volume 9, Number 2, March 2002 http://www.acm.org/dl • ACM Interactions, Volume 8, Number 2, March 2001. • ACM Interactions, Volume 7, Number 2, March 2000. • IEEE Software, 18(1), January/February 2001. Special issue on Usability Engineering. http: //www.computer.org/software/so2001/s1toc.htm • ISO 25062; Software engineering – Software product Quality Requirements and Evaluation (SQuaRE) – Common Industry Format (CIF) for usability test reports. Online Resources • Jakob Nielsen; Guerrilla HCI: Using Discount Usability Engineering to Penetrate the Intimidation Barrier http://www.useit.com/papers/guerrilla_hci.html • Rolf Molich; Comparative Usability Evaluation - CUE; http://www.dialogdesign.dk/cue. html • NIST; Industry Usability Reporting; http://zing.ncsl.nist.gov/iusr/ • Rolf Molich; Usability Test Reports; http://www.dialogdesign.dk/utestreports.html • Jakob Nielsen; Usability Laboratories: A 1994 Survey; http://www.useit.com/papers/ uselabs.html • Microsoft Usability Group; http://microsoft.com/usability/ 139 140 CHAPTER 10. USABILITY IN PRACTICE 10.1 Comparison of Evaluation Techniques Stage of Lifecycle Obj./ Subj. Qual./ Data Quant. Time Equipment Expertise Insp./ Test No. Usab. Specialists No. Users both usage medium low low test 1–2 3–5 quant. usage medium medium medium test 1–2 20+ both usage high medium medium test 1–2 (+4–8 analysts) 3–5 subj. quant. bottomline med./high low med./high insp 1–2 0 subj. qual. process low low medium insp 3–5 0 subj. qual. process medium low low insp 1–2 0 subj. qual. process medium low high insp 3–5 0 observ. qual. process medium low/med. low/med. test 2–4 3–5 observ. qual. process medium low medium test 1–2 >3 subj. quant. medium low low insp 1–2 0 obj. quant. bottomline bottomline high medium med./high test 2–3 20– 50+ obj. quant. medium medium med./high test 2–3 1000s subj. both bottomline both medium low medium 1–2 20+ Exploratory Methods Diary compet. subj. Studies anal. Software compet. obj. Logging anal. Observ. compet. observ. Studies anal. Predictive Methods Action design Analysis Formative Methods Heur. all Eval. Guideline all Checking Cog. all Walkthr. Thinking design Aloud Interviews design Summative Methods Guideline finished Scoring system Formal compet. Experianal., ment finished system A/B Test finished system Question- all naires 10.2 test Discount Usability Engineering “Some usability evaluation is always better than none” [Jakob Nielsen] • User and Task Analysis: observe users on location, keep quiet, don’t interfere. • Scenarios: paper mock-ups, simple prototyping tools. • Heuristic Evaluation: 3 evaluators. • Thinking Aloud: pencil and paper notes, 2–3 users. 10.3 Differences in Evaluation Practices “A recent survey shows that 80% of all Danish drivers think that their driving skills are above average.” 10.3. DIFFERENCES IN EVALUATION PRACTICES 141 How about usability testers? • Take a web site. • Take N professional usability teams. • Let each team evaluate the web site. • Are the results similar? Comparative Usability Evaluation (CUE) • Rolf Molich, DialogDesign, Denmark. • Tutorial and panel at CHI99. • The original materials, team reports, etc. are available at http://www.dialogdesign.dk/cue. html Thanks to Rolf for permission to use his materials in this section. Four Comparative Studies Date Oct 97 Dec 97 Oct 98 Dec 98 Name Student 1 CUE 1 Student 2 CUE 2 Test Interface 9 Danish web sites Windows calendar app 9 Danish web sites hotmail.com Student Teams 50 0 50 2 Prof. Teams 0 4 0 7 All results point in the same direction: teams produce widely differing reports and results! Student 1 and Student 2 • Introductory course in HCI at the Technical University of Copenhagen. • 120 students per course. • Fifty teams of one to three students. • 9 Danish web-sites tested by four to nine teams with at least four test participants. • Quality of evaluations and reports is acceptable considering that most teams used 20-50 hours. Comparative Usability Evaluation 1 (CUE 1) Four professional teams evaluated a Windows calendar program: • Two US teams (Sun, Rockwell), one English (NPL) and one Irish (HFRG, Univ. Cork). • Results published in a panel and a paper at UPA98 [Molich et al., 1998]. 142 CHAPTER 10. USABILITY IN PRACTICE Comparative Usability Evaluation 2 (CUE 2) Nine teams evaluated Hotmail: • seven professional labs and two student teams, • four from Europe, five from the USA. Purpose of study was: a) to investigate the reproducibility of usability test results, and b) to survey the state-of-the art within professional usability testing. not to pick a winner or make a profit. CUE 2 Procedure • Web-site address (www.hotmail.com) disclosed at start of three week evaluation period. • Client scenario provided to teams. • Email access to client through intermediary. • Three weeks to evaluate using each team’s standard approach. • Deliver anonymised usability report. Number of Problems Reported Number of Problems Found Total CUE 2 300 1 1 11 (91%) 128 by seven teams by six teams by five teams by four teams by three teams by two teams by only one team CUE 1 141 1 1 4 4 15 49 (75%) 226 Resources Used per Team Person Hours # Usability Pros # Tests A 136 2 7 B 123 1 6 C 84 1 6 D (16) 1 50 E 130 3 9 F 50 1 5 G 107 1 11 H 45 3 4 J 218 6 6 10.3. DIFFERENCES IN EVALUATION PRACTICES 143 Figure 10.1: Part of the Hotmail resgistration process involved asking for a “password hint question”. Usability Evaluation Reports # Pages Exec. Summary # Screen Shots Severity Scale A 16 y 10 2 B 36 y 0 3 C 10 n 8 2 D 5 n 0 1 E 36 n 1 2 F 19 y 2 1 G 18 n 1 1 H 11 y 2 3 J 22 y 0 4 Usability Results # Positive Findings # Problems Reported % Exclusive % Core (100%=26) Person Hours A 0 B 8 C 4 D 7 E 24 F 25 G 14 H 4 J 6 26 150 17 10 58 75 30 18 20 42 38 71 73 24 35 10 8 57 58 51 54 33 50 56 27 60 31 136 123 84 (16) 130 50 107 45 218 Problem Reported by Seven Teams • During registration process, users asked to enter a “password hint question” (see Figure 10.1). • Most users did not understand the concept of a password hint. • Some users entered their Hotmail password in the hint question box. • Redesigned as “secret question” with careful explanation (see Figure 10.2). Language-Related Problem Reported by all European Teams • To send a new message, users must select the “Compose” button in the left-hand panel (see Figure 10.3). 144 CHAPTER 10. USABILITY IN PRACTICE Figure 10.2: After testing, the dialogue was redesigned as a “secret question”. Figure 10.3: The term “Compose” for writing a new message was not understood by European users. • European users did not understand the term “Compose”. • “Create New Message” or “Write Mail” would be better. Hotmail Summary of Findings From the client’s (Hotmail) point of view, of the 300 findings reported: • New findings (4%) • Vaidation of known issues (67%) • Problems beyond Hotmail usability (29%) – business reasons for not changing. 10.3. DIFFERENCES IN EVALUATION PRACTICES 145 – beyond Hotmail control (partner sites). – problems generic to the web. Current Boundaries to State-of-the-Art • No specific expert user test, although four teams also recruited expert users. • Few tests which required complicated setup, such as sending attachments. • Little testing of boundary conditions, such as a large number of emails in the in-box. Advice for a Usable Usability Report • List problems with a severity rating • State the number of users experiencing the problem. • Include positive findings. • Provide short executive summary. • Keep it short. • Distinguish clearly between: – personal opinions, – expert opinions, – user opinions, and – user findings. Conclusions from CUE Studies • There are overwhelmingly many usability problems. • Many of them are serious. • Limited overlap between team findings. • Many of the teams found more problems than they actually reported. How do you select those to report? • In most cases, no form of cost-effective testing will find all or most of the problems, or even most of the serious ones. • Claims like “Method x finds at least 80% of all serious usability problems” are not in accordance with the results of the CUE studies. 146 CHAPTER 10. USABILITY IN PRACTICE 10.4 Usability Reports 10.4.1 CIF Summative (ISO 25062) • Standard report format for formal experiments. • Grew from the IUSR project at NIST [NIST, 2008] http://zing.ncsl.nist.gov/iusr/ • ISO 25062:2006; Software engineering – Software product Quality Requirements and Evaluation (SQuaRE) – Common Industry Format (CIF) for usability test reports; ISO Standard, 31 Mar 2006. http://iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm? csnumber=43046 CHF 146 ≈ C 90 10.4.2 CIF Formative • Standard report format for thinking aloud tests. • New project at NIST. http://zing.ncsl.nist.gov/iusr/formative/IUSR_Formative/ 10.5 Usability Consulting • EU Usability Network [UsabilityNet, 2005] • Austrian Directory of HCI&UE practitioners [Austrian Computer Society, 2008] Pricing for External Heuristic Evaluation • Nielsen Norman Group: Around US$ 38,000. http://www.nngroup.com/services/inspection.html • Interface Consult, Vienna (Martina Manhartsberger): from around C 600. http://usability. at/leistungen/experten_evaluation.html Pricing for External Thinking Aloud Test • Nielsen Norman Group: Around US$ 30,000. http://www.nngroup.com/services/testing.html • DialogDesign, Copenhagen (Rolf Molich): TA test with 6 users, no video taping, on customer premises C 6,500 (48,000 DKK) http://www.dialogdesign.dk/Prices.htm • Catalysts, Linz: TA test with 4–6 users C 1,440 http://www.dialogdesign.dk/Prices.htm Chapter 11 Visual Design and Typography General Visual Design References • Kevin Mullet and Darrell Sano; Designing Visual Interfaces; Prentice Hall, 1994. ISBN 0133033899 (com, uk) [Mullet and Sano, 1994] • Aaron Marcus; Graphic Design for Electronic Documents and User Interfaces; Addison-Wesley, 1992. ISBN 0201543648 (com, uk) [Marcus, 1992] 11.1 Typography Typography . . . the style and appearance of text. Font Sizes Font sizes are traditionally expressed in printers’ points (pt): 1 pt = 1 pica = 1 72 inch 1 6 inch = ≈ 0.35 mm = ≈ 4.2 mm = 12 pt Serif and Sans Serif Fonts • A serif is a slight projection or embellishment at the end of a letter stroke, as shown in Figure 11.1. • Examples of serif fonts include Times Roman and Georgia. • A sans serif (French = without serif) font does not have such embellishments. • Examples of sans serif fonts include Arial, Helvetica, and Verdana. • When reading passages of text on paper (very high resolution), serif text may be easier to read than san serif, but the evidence is not conclusive [Schriver, 1997, Chapter 5]. See Figure 11.1. 147 148 CHAPTER 11. VISUAL DESIGN AND TYPOGRAPHY serif TT Georgia (serif) Verdana (sans serif) Figure 11.1: Georgia is a serif font, Verdana a sans serif font. Typography References • Paul Kahn and Krzysztof Lenk; Principles of Typography for User Interface Design; interactions, 5(6), 1998. [Kahn and Lenk, 1998] • Robin Williams; Non-Designer’s Type Book; 2nd Edition, Peachpit Press, 2005. ISBN 0321303369 (com, uk) [Williams, 2005] • David Collier; Collier’s Rules for Desktop Design and Typography; Addison-Wesley, 1990. ISBN 0201544164 (com, uk) [Collier, 1990] • Spiekermann and Ginger; Stop Stealing Sheep; 2nd Edition, Adobe Press, 2002. ISBN 0201703394 (com, uk) [Spiekermann and Ginger, 2002] • Jan Tschichold; The Form of the Book; Hartley and Marks, 1997. ISBN 0881791164 (com, uk) [Tschichold, 1997] • Carter, Day, and Meggs; Typographic Design: Form and Communication; Wiley, 2002. ISBN 0471383414 (com, uk) [Carter et al., 2002] 11.2 Factors Influencing the Legibility of Text 11.2.1 Font Type Proportional fonts consume less space and are more legible than fixed width fonts. See Figure 11.2. 11.2.2 Font Size • 10 pt is legible, 11 pt or 12 pt is better. • The distinction between font sizes should be at least 2 pt. [smaller changes cannot be discriminated by the eye] For example, use: • 12 pt for flowing text • 10 pt for subscripts and footnotes • 14 pt for section headings 11.2. FACTORS INFLUENCING THE LEGIBILITY OF TEXT 149 Proportional fonts consume less space and are more legible than fixed width fonts. Proportional fonts consume less space and are more legible than fixed width fonts. Proportional fonts consume less space and are more legible than fixed width fonts. Proportional legible than consume less width fonts. and are more fonts consume less space and are more fixed width fonts. Proportional fonts space and are more legible than fixed Proportional fonts consume less space legible than fixed width fonts. Figure 11.2: Proportional versus fixed width fonts. 2 Sixteen Point Fonts Might Be Used for Titles 2.1 Fourteen Point Fonts for Section Headings Twelve point is great for flowing text such as thisa . Remember that font size changes should be differentiated by at least two points. a 10 pt might be used for subscripts and footnotes. Figure 11.3: Font size changes should be differentiated by at least two points. • 16 pt or larger for titles as shown in Figure 11.3. 11.2.3 Case Mixed case is more compact and legible than all upper case. [Rehe: all upper case slows reading speed by about 12%] This is illustrated in Figure 11.4. Word recognition is based partly on word shape. Lower and mixed case words have more irregular and thus more recognisable word shapes, as shown in Figure 11.5. 11.2.4 Character, Word, and Line Spacing • Character spacing depends largely on font. • Word spacing ≈ width of an ‘n’. See Figure 11.6. • Line spacing ≈ 2 pt. See Figure 11.7. 150 CHAPTER 11. VISUAL DESIGN AND TYPOGRAPHY SETTING A LARGE AMOUNT OF TEXT IN CAPITAL LETTERS SERIOUSLY IMPAIRS LEGIBILITY. UPPER CASE SHOULD ONLY REALLY BE USED FOR EMPHASIS, BUT REMEMBER TO SET THE FONT SIZE A LITTLE SMALLER THAN THAT OF THE SURROUNDING TEXT. Setting a large amount of text in capital letters seriously impairs legibility. Upper case should only really be used for EMPHASIS, but remember to set the font size a little SMALLER than that of the surrounding text. Figure 11.4: Using all upper case slows reading speed. shape SHAPE Figure 11.5: Lower and mixed case words have more recognisable word shapes. word spacing thin space word spacing en space word spacing em space Figure 11.6: En and em word spacing. The space between lines is important. Too much space and lines can float away. Too little space and lines become too densely packed to read comfortably. In the old days strips of lead “leading” were inserted between the lines of type. Nowadays, text processing systems make it easy to experiment with different values of leading. The space between lines is important. Too much space and lines can float away. Too little space and lines become too densely packed to read comfortably. In the old days strips of lead “leading” were inserted between the lines of type. Nowadays, text processing systems make it easy to experiment with different values of leading. Figure 11.7: Too much or too little space between lines makes reading difficult. 11.2. FACTORS INFLUENCING THE LEGIBILITY OF TEXT If a line is too long, readers have difficulty finding the beginning of the next line. The first example here has about 90 characters per line. For books, about 60 characters or ten words per line is about right. Newspaper columns typically have around 30 characters or five words per line. If a line is too long, readers have difficulty finding the beginning of the next line. The first example here has about 90 characters per line. For books, about 60 characters or ten words per line is about right. Newspaper columns typically have around 30 characters or five words per line. If a line is too long, readers have difficulty finding the beginning of the next line. The first example here has about 90 characters per line. For books, about 60 characters or ten words per line is about right. Newspaper columns typically have around 30 characters or five words per line. Figure 11.8: For books, about 60 characters or ten words per line is about right. Newspaper columns typically have around 30 characters or five words per line. 11.2.5 Line Length • ≈ 10 words (60 chars.) per line for books. • ≈ 5 words (30 chars.) per line for newspapers. See Figure 11.8. 11.2.6 Justification Justification is the insertion of extra space within a line to create flush left and right margins. • Justification without hyphenation slows reading due to gaps between words. • Use either flush left, or justified with hyphenation. See Figure 11.9. 11.2.7 Overall Text Environment Maximum of: • two typefaces, 151 152 CHAPTER 11. VISUAL DESIGN AND TYPOGRAPHY Flush left (ragged right) Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them. Flush right (ragged left) Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them. Centered Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them. Justified without hyphenation Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them. Justified with hyphenation Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them. Figure 11.9: Flush and justified text styles. 11.2. FACTORS INFLUENCING THE LEGIBILITY OF TEXT 153 Figure 11.10: A layout grid ensures consistent location and extent of text, columns, titles, and illustrations. • two slants (normal, italic), • two weights (medium, bold), • and four sizes (title, subtitle, text, footnote). 11.2.8 Layout Use an underlying spatial grid to ensure consistent location and extent of text, columns, titles, illustrations, etc., as shown in Figure 11.10. 11.2.9 Margins Avoid “word processor syndrome” (text right up to edge of the window) → leave ample margins. See Figures 11.11 and 11.12. Ample Margins 11.2.10 Typographic Distinction Information is “any difference that makes a difference” [Gregory Bateson] distinction ⇔ information Use typographic distinction such as bold, italics, font change, etc. only if it conveys extra information. 154 CHAPTER 11. VISUAL DESIGN AND TYPOGRAPHY Figure 11.11: Text right up to edge of the window is difficult to read “word processor syndrome”. Figure 11.12: Ample margins all round make the text much easier to read. Chapter 12 Icon Design Icon . . . small visual symbol (broad definition) “A picture is worth a thousand words.” Well-designed icons: • save screen space • are recognised quickly in a busy visual environment • are easily remembered • help interfaces become international. References • William Horton; The Icon Book; John Wiley, 1994. ISBN 0471599018 (com, uk) [Horton, 1994] • Steve Caplin; Icon Design; Watson-Guptill Publications, April 2001. ISBN 0823025225 (com, uk) [Caplin, 2001] • Gregory Thomas; How to Design Logos, Symbols and Icons; How Design Books, April 2003. ISBN 1581804563 (com, uk) [Thomas, 2003] • Rudolf Modley; Handbook of Pictorial Symbols; Dover Publications, New York, 1976. ISBN 048623357X (com, uk) [Modley, 1976] • Henry Dreyfuss; Symbol Sourcebook; Wiley, 1984. ISBN 0442218060 (com, uk) [Dreyfuss, 1984] Online Resources • Matt Queen; Icon Analysis: Evaluating Low Spatial Frequency Compositions; http://www. boxesandarrows.com/view/icon_analysis • Uday Gajendar; Learning to Love the Pixel: Exploring the Craft of Icon Design; http://www. boxesandarrows.com/view/learning_to_love_the_pixel_exploring_the_craft_of_icon_design • SYMBOLS.com http://www.symbols.com/ 155 156 CHAPTER 12. ICON DESIGN Border Background Image Label Figure 12.1: The standard parts of an icon. • Mark James; Silk Icons; http://www.famfamfam.com/lab/icons/silk/ • The Icon Depot http://www.geocities.com/SiliconValley/6603/icon.htm • Realm Graphics Web Images http://www.ender-design.com/rg/ • Anthony’s Icon Library http://www.sct.gu.edu.au/˜anthony/icons/ • WinSite Icon Archive http://www.winsite.com/win95/icons/ 12.1 Visual Association Which companies do these logos represent? 12.2 Standard Parts of an Icon • Border • Background • Image • Label See Figure 12.1. 12.3. ICON DESIGN PRINCIPLES 157 Figure 12.2: Visually imbalanced icons. On the left, the icon palette from an early version of Paintbrush for Windows. On the right, the redesigned icons from MS Paint. 12.3 Icon Design Principles 12.3.1 Coherency • Design a set of icons as a whole. • Icon set should be consistent in terms of size, colours, metaphor, level of realism (abstraction), etc. • The icons in a set should be visually balanced. • Visual distinctions should have significance – extraneous decorations distract. Visually Imbalanced Icons An early version of Paintbrush displayed visually incoherent icons, as can be seen on the left in Figure 12.2. • The lower icons are simple and visually lightweight, the upper icons are very full (heavy). • The redesigned icons in MS Paint (on the right) are more balanced and consistent. Levels of Realism From photorealistic to a simple silhouette: • Photograph • Drawing • Caricature • Outline 158 CHAPTER 12. ICON DESIGN Figure 12.3: Mixed levels of realism in icons. Many of the icons from SGI’s IRIX systems are photorealistic. However, some icons break the mould, like the abstract icons in the bottom right. • Silhouette However, stick to just one level of realism, unlike the mixture of levels of realism illustrated in Figure 12.3. Symbols can also be drawn at different levels of abstraction, as shown in Figure 12.4. 12.3.2 Legibility • As far as the pixel real estate allows, use large objects, bold lines, and simple areas. • Take into account screen resolution and viewing distance. • Good foreground/background contrast. • Avoid arcs and oblique lines (“jaggies”). • External shape (silhouette) conveys most info. Typical Viewing Distances • A desktop monitor: 60cm. • A paper document: 45cm. • A laptop screen: 30cm. A 30 by 30 pixel icon will appear much larger at 30cm on an 11 inch 640 by 480 laptop screen, than at 60cm on a 17 inch 1280 by 1024 workstation monitor. See Figure 12.5. Silhouette Conveys Most Information The external shape (silhouette) of a symbol conveys the most information. See Figure 12.6. 12.3. ICON DESIGN PRINCIPLES 159 Figure 12.4: Symbols for men and women at different levels of abstraction. 60 cm 45 cm 30 cm Figure 12.5: Typical viewing distances to icons. Figure 12.6: Simple aircraft outlines to denote arrivals and departures areas in an airport. Note how the silhouette conveys all of the information. 160 CHAPTER 12. ICON DESIGN Figure 12.7: Garish multicolour icons competing for the user’s visual attention in a Windows 3.1 desktop. 12.3.3 Recognition and Recall • Where possible, choose a metaphor familiar to the viewer. • Use concrete objects wherever possible, abstract concepts and actions are difficult to visualise. • Do you know of a good icon for “Shortcut”? • For years there was no good icon for the concept of “Undo”, but in the meantime there is a convention of a backwards curving arrow. • Provide textual labels (at least by default). 12.3.4 Use Colour Sparingly • Design first for black and white, add any colour later. • Gratuitous use of colour overloads the viewer, use grey tones and one or two colours. 12.4 Cultural and International Issues • Beware of using text or alphabetic characters inside an icon (as opposed to the label). Otherwise, different language versions of the icon will probably be needed. See Figure 12.10. • Hand symbols, facial appearances, etc. vary immensely from culture to culture → don’t use them in icons. • Beware also of metaphors dependent on a particular culture, e.g. the US mailbox for incoming mail. See Figure 12.11. 12.4. CULTURAL AND INTERNATIONAL ISSUES Figure 12.8: A well-balanced, consistent set of icons with restrained use of colour. Figure 12.9: The evolution of the Microsoft Word icon bar from simple greyscale to limited use of colour. Figure 12.10: Icons from the English and German versions of Word97. Text or alphabetic characters within an icon are language-dependent and will often have to be translated. Figure 12.11: Two icons for incoming mail from different versions of Unix. The US mail box is unrecognisable for many Europeans; the letter tray is more universal. Note that these icons also use text within the icons proper which may need to be translated. 161 162 CHAPTER 12. ICON DESIGN Figure 12.12: Icons for various types of food and drink area. What do the icons mean? Bar Snacks Selfservice Restaurant Figure 12.13: Compared to the iconic representations in the previous figure, here words convey the subtle distinction better. 12.5 Do Not Always Use Icons For more abstract concepts and subtle distinctions, verbal representations can sometimes work better than iconic representations. See Figures 12.12 and 12.13. 12.6. ICONIC LANGUAGE 12.6 163 Iconic Language For larger sets of icons, it is often useful to develop an iconic language. An iconic language is a systematic way of combining elementary symbols into more complex icons: • Vocabulary: set of primitive symbols. • Grammar: rules for combining them. Example Iconic Language – Windows NT 4.0 (95) Primitive symbols for application and document types are combined: Document = Application + DocType [+ Template] [+ Assistant] When a document is a template, or an assistant is provided, these symbols are added, as shown in Table 12.1. Example Iconic Language – Harmony Primitive symbols for document, link, and visited are combined for various types of document in the Harmony authoring tool for Hyperwave web servers [Andrews, 1996]. Document = [Link to] + DocType [+ Visited] See Table 12.2. 164 CHAPTER 12. ICON DESIGN Elementary Symbols Document Assistant Template Document Types Text document Spreadsheet document Presentation document Database document Applications Word Excel Powerpoint Access Generated Icons Word text document Excel spreadsheet document Powerpoint presentation document Access database document Word template Powerpoint template Access template Word template assistant Powerpoint template assistant Access template assistant Table 12.1: Iconic language for Windows NT 4.0 documents. 12.6. ICONIC LANGUAGE Elementary Symbols Document Link Visited Generated Icons Text document Visited text document Link to text document Visited link to text document Image document Visited image document Link to image document Visited link to image document 3D model Visited 3D model Link to 3D model Visited link to 3D model Table 12.2: Iconic language for document and link icons in Harmony. 165 166 CHAPTER 12. ICON DESIGN 12.7 The Icon Design Lifecycle Usability engineering lifecycle for icons: Design, test, redesign. See Figure 12.14. Icon Design Iterations • Start with simple black and white, hand-drawn sketches on paper (silhouette conveys the most information). • Test and redesign until the basic symbols work. • Add greys and perhaps colour. Design on computer. Print out colour versions of the designs, at the approximate real size. • Test and redesign until the icons work. Icon Intuitiveness Testing Test the intuitiveness of (a set of) icons by running a simple thinking aloud usability test: • Mount each icon design on a piece of card. • Either tape up an area of the table with masking tape, into which the icons are placed, as shown in Figures 12.15 and 12.16. This is so the video camera remains focussed and test users are less tempted to pick up the icon cards. Better still, use a stand to present icon designs at approximately the correct viewing angle and distance. • The test facilitator places the icons one after the other in a random sequence into the taped up area or onto the stand. • Use thinking aloud to capture: – the user’s initial reaction – what they think the symbol is, – and what they think it might be intended to represent. See Figure 12.16. • At the end of the test, interview the test user in more detail. Provide an overview sheet/printout of all the icons to aid the discussion. An Icon Test in Progress 12.7. THE ICON DESIGN LIFECYCLE 167 Gather info on users and tasks User Profile Tasks Analyse product Design iconic language Iconic Primitives Icon Sketches Design icons Test icons as a set Test Report Integrate icons into interface Test interface Figure 12.14: The icon design lifecycle. Based on the figure on page 270 of [Horton, 1994]. Mirror Taped Up Area Observers Microphone Test Facilitator Participant Video Camera Figure 12.15: Test setup for an icon intuitiveness test. 168 CHAPTER 12. ICON DESIGN Figure 12.16: An icon intuitiveness test in progress. Each icon is printed out in colour and mounted on card. The taped up area of the desk keeps the icon in camera view. Figure 12.17: Room setup for an icon test. Note the video camera and clip-on microphone. 12.8. DESIGNING ICONS FOR SUN’S PUBLIC WEB SITE 169 Figure 12.18: Eight iterations of the icon design for “Products and Solutions”. Between each iteration, icon testing was carried out. [Thanks to Jakob Nielsen for permission to use these images.] 12.8 Designing Icons for Sun’s Public Web Site • In the spring of 1995, Sun Microsystems’ public web site was redesigned. • Icons were used to represent parts of the web site, such as “Technology and Developers”, “Products and Solutions”, and “Sun on the Net”. • Thanks to Jakob Nielsen for permission to use the material in this section. Icon Designs for Concept of “Technology and Developers” Three rounds of icons were designed and tested to represent the concept of “Technology and Developers”, as can be seen in Tables 12.3, 12.4, and 12.5. Icon Designs for Concept of “Products and Solutions” Figure 12.18 shows the iterations of icon designs for the concept of “Products and Solutions”. Icon Designs for Concept of “Sun on the Net” Figure 12.19 shows the iterations of icon designs for the concept of “Sun on the Net”. 170 CHAPTER 12. ICON DESIGN Icon Intended Meaning User Interpretation Chip, CD-ROM. Too hard, finished product. Computer, chip. Too hard, finished product. Construction worker. Negative connotation of “under construction”. Table 12.3: Initial set of black and white designs for an icon to represent the concept of “Technology and Developers” and their interpretation after user testing. [Thanks to Jakob Nielsen for permission to use these images.] Icon Intended Meaning User Interpretation Developer, construction. Liked most, but too much emphasis on hardware. Developer, power. Liked idea of “harnessing the power”. Developer, computer. Table 12.4: Second round of icon sketches for “Technology and Developers”. [Thanks to Jakob Nielsen for permission to use these images.] Icon Intended Meaning Developer, power, construction. User Interpretation “Thunder and lightning”, “electric - looks painful”, “person being killed by technology”, “dance machine”, “why do Sun developers look bug-eyed?”. Power and cog wheels. Lightning striking machinery. CD-ROM wheels. Development and engineering. and cog- Table 12.5: Third round of icons for “Technology and Developers”. The most promising of the black and white designs have been drawn on computer and colour has been added. [Thanks to Jakob Nielsen for permission to use these images.] 12.8. DESIGNING ICONS FOR SUN’S PUBLIC WEB SITE Figure 12.19: Twelve iterations of the icon design for “Sun on the Net”. Between each iteration, icon testing was carried out. [Thanks to Jakob Nielsen for permission to use these images.] 171 172 CHAPTER 12. ICON DESIGN Chapter 13 A Brief History of HCI References ++ Adele Goldberg; A History of Personal Workstations; Addison-Wesley, 1988. ISBN 0201112590 (com, uk) [Goldberg, 1988] + Brad Myers; A Brief History of Human-Computer Interaction Technology; ACM interactions, 1998. [Myers, 1998] Online Resources • Matthias Rauterberg ; History of HCI ; http://www.idemployee.id.tue.nl/g.w.m.rauterberg/ presentations/HCI-history/index.htm • Wikipedia; History of the Graphical User Interface; http://en.wikipedia.org/wiki/History_ of_the_graphical_user_interface • Wikipedia; WIMP (computing); http://en.wikipedia.org/wiki/WIMP_(computing) • Howard Rheingold; Tools For Thought; http://www.rheingold.com/texts/tft/ • DigiBarn Computer Museum; http://www.digibarn.com/ • Computer History Museum; http://www.computerhistory.org/ • IFIP WG 9.7; History of Computing; http://www.comphist.org/ Other Resources • Bob Cringely; Triumph of the Nerds; Three-part TV series made for PBS in USA in 1996. Inlcudes interviews with Bill Gates, Steve Jobs, and many others. The VHS version is 200 minutes, the DVD version is cut down to 150 minutes. Also available on youtube http://www.youtube.com/view_play_list?p=4D5CD637F73C24C7 and Google Video. 173 174 CHAPTER 13. A BRIEF HISTORY OF HCI 13.1 Early Interfaces Memex (1945) • Vannevar Bush, 1945 [Bush, 1945a]. • Memex = “memory extender”. • Hypothetical design (never built) based on microfilm technology and mechanical levers integrated into a large desk. • Vision of document repository with links between documents. • “Trails” = chained sequence of links. • Personal annotations. Memex Chronology • Bush started to formulate Memex ideas in 1932 [Nyce and Kahn, 1991, page 42]. • Draft sent to FORTUNE magazine on 07 Dec 1939 [Nyce and Kahn, 1991, page 52], but publication delayed by USA entering World War 2. • Bush was presidential science advisor during World War 2. • Memex article finally published in July 1945 in the Atlantic Monthly [Bush, 1945a]. • A condensed version, with new illustrations by Alfred D. Crimi, was printed on 10 Sep 1945 in LIFE Magazine [Bush, 1945b]. • Later also reprinted in Nyce and Kahn [1991] and Bush [1996]. • Second, revised article published in 1967 [Bush, 1967], also reprinted in Nyce and Kahn [1991]. SketchPad (1963) • Ivan Sutherland, PhD Thesis, MIT, 1963. • Drawing editor with built-in constraint solver. • First graphical user interface: using a CRT and a lightpen (and various switches and knobs). • First use of “windows” (virtual sheets of paper). • First object-oriented program. • Original PhD (scanned by MIT) [Sutherland, 1963a], reconstructed electronic edition produced by University of Cambridge [Sutherland, 1963b]. • Some video of SketchPad can be seen on Alan Kay’s video [Kay, 1987, at 00:04:06] and in the 1964 Science Reporter episode [Fitch, 1964]. 13.1. EARLY INTERFACES Figure 13.1: The memex device. [Screen shot from the Memex animation [Adelman and Kahn, 1995], used with kind permission of Paul Kahn.] Figure 13.2: Part of a trail (A5) about the English long bow. Here a link between pages 3GK27 and 5AKD78R. [Screen shot from the Memex animation [Adelman and Kahn, 1995], used with kind permission of Paul Kahn.] 175 176 CHAPTER 13. A BRIEF HISTORY OF HCI Figure 13.3: Ivan Sutherland’s SketchPad system. [Image taken from the sun.com web site (it is no longer there) and used under the terms of the Sun Microsystems Copyright Notice (see page xiii). ] Augment/NLS (1968) • Doug Engelbart, Augmentation Research Center (ARC) of Stanford Research Institute (SRI), 1968. • First use of the mouse. • First raster-scan (pixel-based) monitor. • Mouse and five-chord keyboard for most interaction, keyboard only for entering longer pieces of text. • First practical implementation of hypertext links. • Drawing editor and image links. • Interactive collaboration: multiple people could point and edit and see each other’s pointers. • Famous live demo “Mother of all Demos” [Wikipedia, 2009] at AFIPS Fall Joint Computer Conference (FJCC), San Francisco, 09 Dec 1968. Engelbart and NLS Resources • Augment concept paper [Engelbart, 1962]. • Comparative study of different input devices [English et al., 1967]. • The mouse patent [Engelbart, 1970], filed in 1967, expired in 1987. • The Bootstrap Institute [Engelbart, 2008]. 13.2. WIMP INTERFACES 177 Figure 13.4: The Augment/NLS Production Mouse used by Doug Engelbart in the famous 1968 live demo. [ Image used with kind permission of Stanford University, Special Collections. ] • Video interviews and background material at Invisible Revolution [Hegland and Klijnsma, 2008]. • Video of “The Mother of all Demos” can also be seen on Alan Kay’s video [Kay, 1987, at 00:10:55]. 13.2 WIMP Interfaces WIMP stands for “window, icon, menu, pointing device”. Xerox Alto (1973) • Xerox Palo Alto Research Center (PARC) opened 01 Jul 1970. • Xerox licensed the mouse from SRI in 1971. • Xerox Alto was built in 1973. • The first “personal computer”, designed to be used by only one person (a very radical idea at the time). • Several thousand Altos were built, but it was never released commercially. Alto GUI • Raster graphics display with pixels: black and white 808 × 606 pixels resolution. • windows 178 CHAPTER 13. A BRIEF HISTORY OF HCI • a mouse and a cursor • pop-up menus • Word processor (Bravo) Bravo and BravoX Bravo (and later BravoX) was a word processor developed for the Alto by Charles Simonyi and Butler Lampson: • WYSIWYG (what you see is what you get) • split screen • bold and italic • font families • variable-width characters (proportional fonts) Simonyi later joined Microsoft and led development of Microsoft Word. 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