Education decisionmakers need access to the best evidence about the effectiveness of education interventions, including practices, products, programs, and policies. It can be difficult, time consuming, and costly to access and draw conclusions from relevant studies about the effectiveness of interventions. The What Works Clearinghouse (WWC)…

Treatment effect estimates from a "regression discontinuity design" (RDD) have high internal validity. However, the arguments that support the design apply to a subpopulation that is narrower and usually different from the population of substantive interest in evaluation research. The disconnect between RDD population and the…

When randomized experiments are infeasible, quasi-experimental designs can be exploited to evaluate causal treatment effects. The strongest quasi-experimental designs for causal inference are regression discontinuity designs, instrumental variable designs, matching and propensity score designs, and comparative interrupted time series designs. This…

This report summarizes the complex research literature on quantitative methods for assessing how impacts of educational interventions on instructional practices and student learning differ across students, educators, and schools. It also provides technical guidance about the use and interpretation of these methods. The research topics addressed…

This review focuses on what the author terms a reconsideration of the working credentials of the randomly controlled trial (RCT) design, and includes a discussion of popularly accepted aspects as well as some new perspectives. The author concludes that there is nothing either Imperative or superior about the need for RCT designs, and that an…

In the present climate of public accountability, there is increasing demand to show "what works" and what return is gained for the public from investments to improve communities. This increasing demand for accountability is being met with growing confidence in the field of philanthropy during the past 10 years that the impact or effectiveness of…