Week 8_groupdesigns2 - ScWk 240 Research Methods and Design...

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1 ScWk 240 Research Methods and Design Week 8 October 17, 2008 San José State University Edward Cohen, Ph.D. Today: Review of test Group designs and internal validity Questions about Literature Review (note: due date now 10/30/08 at beginning of class) Group Designs: Pre-experimental, Experimental & Quasi-Experimental designs “The great secret of doctors…is that most things get better by themselves; most things, in fact, are better in the morning.” Dr Lewis Thomas, President, Memorial Sloan-Kettering Institute for Cancer Research 1976 I. Review: A. What are the three requirements to show causality? 1. ______________ Time ordering 2. ______________ Association or correlation between IV and DV 3. ______________ Change in DV not caused by third variable (rival hypothesis) B. In a study of the effectiveness of a parent education group on improving parenting skills, some parents may get parenting advice from friends during the experiment. Give an example of a rival hypothesis What is the rival hypothesis? (Answer: getting advice from friends.) . II. What is “ research design ”? The decisions made in planning and conducting your research so as to best answer your research questions. A. Research designs can be cross-sectional (“a point in time”), or longitudinal (“different points in time”) B. Cross sectional designs are typical for descriptive research (e.g. “What is the prevalence of mental illness in the homeless population?”) C. Longitudinal designs are typical in evaluative research. Testing a treatment almost always requires obtaining data at different points in time ***As you look through the various types of Groups Designs (see Appendix 2.), which ones are cross-sectional? Î Note: for your project, your specific research design will be described in the Method section, under the subheading Research Design
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2 III. Group Designs – now we’re only talking about evaluative topics—testing the effects (or effectiveness) of treatment interventions, new programs, policy changes R Random assignment O Observation or measurement (of dependent variable Y) O 1 , O 2 Observations or measurements (of dependent variable Y) at time 1 and time 2 X Intervention, treatment or event (independent variable) IV. Classical experimental design—the Pretest Posttest Control Group Design A. Sample selected from population by either probability or non-probability sampling B. Random assignment of sample to either experimental or control group C. Take pretest measurement(s) prior to intervention D. Take posttest measurement(s) after intervention
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This note was uploaded on 09/08/2010 for the course SCWK 298 at San Jose State University .

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Week 8_groupdesigns2 - ScWk 240 Research Methods and Design...

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