The review uses a form of best evidence synthesis (Slavin, 1986), adapted for use in reviewing ‘what works’ literatures in which there are generally few studies evaluating each of many programmes (see Slavin, 2008). Best-evidence syntheses apply consistent, well-justified standards to identify unbiased, meaningful information from experimental studies, discussing each study in some detail, and pooling effect sizes across studies in substantively justified
categories. The method is very similar to meta-analysis (Cooper, 1998; Lipsey & Wilson, 2001), adding an emphasis on narrative description of each study’s contribution.
The full report includes more details on the review methods and search procedures.