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…

Programs that improve teaching effectiveness represent a core strategy to improve student educational outcomes and close student achievement gaps. This article compiles empirical values of intraclass correlations for designing effective and efficient experimental studies evaluating the effects of these programs. The Early Childhood Longitudinal…

This study explores the extent to which differences in research design explain variation in Head Start program impacts. We employ meta-analytic techniques to predict effect sizes for cognitive and achievement outcomes as a function of the type and rigor of research design, quality and type of outcome measure, activity level of control group, and…

Drawing on our five years of experience developing WWC evidence standards and reviewing studies against those standards as well as current literature on the design of impact studies, we highlight in this paper some of the most critical issues and common pitfalls in designing and conducting impact studies in education, and provide practical…

This article examines the power analyses for the first wave of group-randomized trials funded by the Institute of Education Sciences. Specifically, it assesses the precision and technical accuracy of the studies. The authors identified the appropriate experimental design and estimated the minimum detectable standardized effect size (MDES) for each…

This article presents evidence from a national evaluation of the effects of 21st Century Community Learning Center after-school programs. The study was conducted in 12 school districts and 26 after-school centers, at which 2,308 elementary school students who were interested in attending a center were randomly assigned either to the treatment or…

While policy analysis is currently the most popular research strategy for educational administration, it is more effective when used in conjunction with program evaluation. The relationship between these methods is illustrated by examining alternative research designs for a hypothetical school drug abuse program. (BS)

ifferent evaluation models were applied to data from a high school career education program to investigate problems in statistical conclusion validity and program effectiveness judgments. If potential threats to internal validity are analyzed and protection strategies are developed, more confidence in unplanned ex post facto design using a…