Over the past 15 years, we have seen an increase in the use of cluster randomized trials (CRTs) to test the efficacy of educational interventions. These studies are often designed with the goal of determining whether a program works, or answering the what works question. Recently, the goals of these studies expanded to include for whom and under…

This "What Works Clearinghouse Procedures and Standards Handbook (Version 3.0)" provides a detailed description of the standards and procedures of the What Works Clearinghouse (WWC). The remaining chapters of this Handbook are organized to take the reader through the basic steps that the WWC uses to develop a review protocol, identify…

An effect size of about 0.70 (or 0.40-0.70) is often claimed for the efficacy of formative assessment, but is not supported by the existing research base. More than 300 studies that appeared to address the efficacy of formative assessment in grades K-12 were reviewed. Many of the studies had severely flawed research designs yielding…

The use of educational technology in K-12 classrooms has been gaining tremendous momentum across the country since the 1990s. Many school districts have been investing heavily in various types of technology, such as computers, mobile devices, internet access, and interactive whiteboards. Almost all public schools have access to the internet and…

The present review examines research on the effects of technology use on reading achievement in K-12 classrooms. Unlike previous reviews, this review applies consistent inclusion standards to focus on studies that met high methodological standards. In addition, methodological and substantive features of the studies are investigated to examine the…

This paper details the challenges encountered by authors summarizing evidence from a primary study to describe a treatment's effectiveness using an effect size (ES) estimate. Dilemmas that are encountered, including how to calculate and interpret the pertinent standardized mean difference ES for results from studies of various research designs,…

Meta-analysis of 143 effect sizes in 43 studies of adventure programming for adolescents found an overall effect size of 0.31. Summary effect sizes of outcome categories differed significantly among categories, however. Effect size was related to program length and participant age but not to delinquent status. Discusses the lack of pertinent…

Because research synthesis enables one to determine either the overall effectiveness of a particular treatment or the relative effectiveness of different types of treatments, it is becoming increasingly popular as a tool in program evaluation. Numerous methodological problems arise, however, when research synthesis is applied to studies conducted…

Meta analysis results were compared with a traditional review of bilingual education program effectiveness. When controlled for methodological inadequacies, participation in bilingual education programs consistently produced differences favoring bilingual education. The methodological inadequacies in the synthesized studies highlights the need for…