The What Works Clearinghouse (WWC) identifies existing research on educational interventions, assesses the quality of the research, and summarizes and disseminates the evidence from studies that meet WWC standards. The WWC aims to provide enough information so educators can use the research to make informed decisions in their settings. This…

The What Works Clearinghouse (WWC) evaluates research studies that look at the effectiveness of education programs, products, practices, and policies, which the WWC calls "interventions." Many studies of education interventions make claims about impacts on students' outcomes. Some studies have designs that enable readers to make causal…

The What Works Clearinghouse (WWC) Standards Briefs explain the rules the WWC uses to evaluate the quality of studies for practitioners, researchers, and policymakers. Attrition (loss of sample) occurs when individuals initially included in a study are not included in the final study analysis. Attrition is a common issue in education research and…

The purpose of this guide is to provide clear, practical advice on reporting the results of an evaluation of an educational program or practice ("intervention"). Specifically, this is a guide for researchers, and those who sponsor and use research, to reporting the results of "impact" studies--that is, studies that evaluate the…