1. Chapter 9 Group-Level Research Designs

2. CHARACTERISTICS OF “IDEAL” EXPERIMENTS Controlling the Time Order of Variables Manipulating the Independent Variable Establishing Relationships Between Variables Controlling Rival Hypotheses Holding Extraneous Variables Constant Using Correlated Variation Using Analysis of Covariance Using a Control Group Randomly Assigning Research Participants to Groups Matched Pairs

3. THREATS TO INTERNAL VALIDITY History Maturation Testing Instrumentation Error Statistical Regression Differential Selection of Research Participants Mortality Reactive Effects of Research Participants Interaction Effects Relations Between Experimental and Control Groups –Diffusion of treatments –Compensatory equalization –Compensatory rivalry –Demoralization

4. THREATS TO EXTERNAL VALIDITY Pretest-treatment Interaction Selection-treatment Interaction Specificity of Variables Reactive Effects Multiple-treatment Interference Researcher Bias

5. EXPLORATORY GROUP RESEARCH DESIGNS One-group Posttest-only Design Cross-sectional Survey Design Multi-group Posttest-only Design Longitudinal Case Study Design Longitudinal Survey Design Trend studies Cohort studies Panel studies

6. DESCRIPTIVE GROUP RESEARCH DESIGNS Randomized One-group Posttest-only Design Randomized Cross-sectional Survey Design One-group Pretest-posttest Design Comparison Group Posttest-only Design Comparison Group Pretest-posttest Design Interrupted Time-series Design

7. EXPLANATORY GROUP RESEARCH DESIGNS Classical Experimental Design Randomized Posttest-only Control Group Design