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Unformatted text preview: stency is the most important design principles for usable systems. This can be
applied at multiple levels; at first a system should at the bare minimum be consistent
within itself. For example, navigation constructs should not change across different
parts of the system. If the selection of a check box button in one part of the system
indicates that a feature is active, this should be the standard thought-out the system.
Therefore, users should not have to wonder whether different words, situations, or
actions mean the same thing. Better to follow platform conventions. Nielsen (1990)
5. Error Prevention
According to Nielsen (1990) good error messages that make sense to the user are always
necessary. It is ideal to create a “careful design” which prevents a problem from
occurring in the first place. Error-prone conditions should be eliminated or check for
them and present users with a confirmation option before they commit to an action.
6. Recognition versus Recall
Nielsen (1990) recommends that the user's memory load should be minimized by
making objects, actions, and options visible. The user should not have to remember
information from one part of the dialogue to another part. Instructions for use of the
system should be clearly visible or else easily retrievable whenever needed. We see this
principle in use every day, in street signs, the letters painted on keyboard key caps,
iconic instructions for using a gasoline pump to fill our cars etc. The secret is to strike a
balance between knowledge that is stored in the head and information that is
externalized. Too much reliance on memorized information makes a system difficult to
learn and use.
7. Flexibility of use
According to Nielsen (1990) system should be flexible to use for every one. Since,
user’s levels of experience with systems can very; this leads to the necessity of having 39 multiple “views” of users. Mainly, users can be divided into four types based on their
experience and comfort level with a given system:
i). Novice users: has little to no experience using system. Must often consult user
manual, online help etc. Enjoys a minimal use of system functionality.
ii). Intermediate users: are familiar with many aspects of system. Consults the manual
infrequently and able to perform most tasks with ease.
iii). Power user: know the system very well from an end-user perspective. Actively
seeks way to optimize performance by using hidden “accelerator” aspect. Almost never
iv). Expert user: not only knows how to use system, but also understands its internal
working. Therefore, system should be flexible to cater both inexperienced and
8. Aesthetic and minimalist design
According to Nielsen (1990) dialogues should not contain information which is
irrelevant or not often needed. Each extra unit of information in a dialogue competes
with the relevant units of information and reduce its relative visibility.
9. Sensible error messages
According to Nielsen (1990) error messages should be expressed in plain language (no
codes), precisely indicate the problem, and constructively suggest a solution. Ideally,
error message should explain what happened in terms of understanding to the user. One
of the most important heuristics in usability is to use the user’s natural language. This is
particularly true with regard to error messages, since user is the most in need of good
usability when a system is not performing as expected. The designers should avoid
using any system or technical language which is not easily understandable by common
10. Help and documentation
According to Nielsen (1990) it is an ideal situation that a system can be used without
documentation, however sometime it may be necessary to provide help and
documentation for particular system. This is rarely the case with wireless applications,
since most wireless application binaries are too small to become overly complex. Any
such information (documentation) should be easy to search, focused on the user's task,
list concrete steps to be carried out and should not be too big. 40 CHAPTER 3. CONCEPTUAL FRAMEWORK According to Miles and Huberman (1994, p.18) “The conceptual framework explains,
either graphically or in narrative form, the main things to be studied.” In our previous
chapters presented we have described background and problem discussion about our
research purpose. In this chapter we will take concepts from literature review to build
our conceptual framework:
RQ 1. Does the design of current WAP services contain major usability flaws?
In the previous section, we have studied usability engineering, usability principles,
usability attributes and usability principles for WAP services. We found that earlier
research conducted by Ramsay 2001, Condos et al, 2002 and Nielsen 1993 is very much
useful to answer our first research question to workout does the design of current WAP
services contain major usability flaws?
Usability Principles for WAP Services defined by Condos et al., (2002) Avoid unnecessary use of graphics
Avoid long lists and indicate the length of the list
Make important options visible to the user
Provide clear, helpful and meaningful error messages
Avoid dead ends
Format and present content appropriately
Offer consistency in navigation and naming of menu options
Provide the user with sufficient prompting
Minimize user input
Structure tasks to aid the user...
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- Fall '13
- The Land