1. Research Synthesis (Meta-Analysis) Research Synthesis (Meta-Analysis) CHAPTER 1 CHAPTER 10

2. Contrasting Meta-Analysis With Literature Review How thorough was the literature search? On what basis were studies included or excluded? -Computer search and hand search -Which journals? -Theses and dissertations included? -Perceived internal validity -Sample size -Design (continued)

3. Contrasting Meta-Analysis With Literature Review How did the author arrive at conclusions? -Vote counting -Differential weighting

4. Purpose of Meta-Analysis Answer an important question when adequate literature is available. Report a definitive methodology for the review. Quantify the results of studies using a standard metric.

5. Steps in a Meta-Analysis Identification of a problem Literature searched by specified means Review of studies to determine inclusion or exclusion Careful reading and evaluation to identify and code important study characteristics Calculating effect size Applying appropriate statistical analyses Reporting all the steps and outcomes in a paper

6. Calculating Effect Size

7. Distribution Overlap When Group 1 and Group 2 Are 1s Apart (ES = 1.0)

8. Methodological Considerations in Meta-Analysis Deciding what to code: Using theory and empirical studies to decide on characteristics of importance Choosing the standard deviation for ES -Experimental versus control -Nonrandomly formed groups (sex, age) -Pretest to posttest Correcting ES Weighting ES