ABSTRACT
Step 1: Finding studies (e.g. published/unpublished reviews) from which effect sizes can be computed. Step 2: Coding the study characteristics (e.g. date, publication status, design characteristics, quality of design, status of researcher). Step 3: Measuring the effect sizes (e.g. locating the experimental group as a z-score in the control group distribution) so that outcomes can be measured on a common scale, controlling for ‘lumpy data’ (nonindependent data from a large data set). Step 4: Correlating effect sizes with context vari ables (e.g. to identify differences between well-controlled and poorly controlled studies).
