Evaluators of education interventions are increasingly designing studies to detect impacts much smaller than the 0.20 standard deviations that Cohen characterized as "small." While the need to detect smaller impacts is based on compelling arguments that such impacts are substantively meaningful, the drive to detect smaller impacts may…

Rigorous evidence of program effectiveness has become increasingly important with the 2015 passage of the Every Student Succeeds Act (ESSA). One question that has not yet been fully explored is whether program evaluations carried out or commissioned by developers produce larger effect sizes than evaluations conducted by independent third parties.…

Evaluators of education interventions increasingly need to design studies to detect impacts much smaller than the 0.20 standard deviations that Cohen (1988) characterized as "small." For example, an evaluation of Response to Intervention from the Institute of Education Sciences (IES) detected impacts ranging from 0.13 to 0.17 standard…

Underlying all What Works Clearinghouse (WWC) products are WWC Study Review Guides, which are intended for use by WWC certified reviewers to assess studies against the WWC evidence standards. As part of an ongoing effort to increase transparency, promote collaboration, and encourage widespread use of the WWC standards, the Institute of Education…

Interest in the regression discontinuity (RD) design as an alternative to randomized control trials (RCTs) has grown in recent years. There is little practical guidance, however, on conditions that would lead to a successful RD evaluation or the utility of studies with underpowered RD designs. This article describes the use of RD design to…

This document provides step-by-step instructions on how to complete the Study Review Guide (SRG, Version S3, V2) for single-case designs (SCDs). Reviewers will complete an SRG for every What Works Clearinghouse (WWC) review. A completed SRG should be a reviewer's independent assessment of the study, relative to the criteria specified in the review…

Using exogenous characteristics to identify endogenous subgroups, the approach discussed in this method note creates symmetric subsets within treatment and control groups, allowing the analysis to take advantage of an experimental design. In order to maintain treatment--control symmetry, however, prior work has posited that it is necessary to use…

As evidence-based reform becomes increasingly important in educational policy, it is becoming essential to understand how research design might contribute to reported effect sizes in experiments evaluating educational programs. The purpose of this study was to examine how methodological features such as types of publication, sample sizes, and…

With research indicating substantial differences among teachers in terms of their effectiveness (Nye, Konstantopoulous, & Hedges, 2004), a major focus of recent research in education has been on improving teacher quality through professional development (Desimone, 2009; Institute of Educations Sciences [IES], 2012; Measures of Effective…

The purpose of this study is to extend the work of Spybrook and Raudenbush (2009) and examine how the research designs and sample sizes changed from the planning phase to the implementation phase in the first wave of studies funded by IES. The authors examine the impact of the changes in terms of the changes in the precision of the study from the…

This review examines the effectiveness of educational technology applications in improving the reading achievement of struggling readers in elementary schools. The review applies consistent inclusion standards to focus on studies that met high methodological standards. A total of 20 studies based on about 7,000 students in grades K-6 were included…

The purpose of this review is to learn from rigorous evaluations of alternative technology applications how features of using technology programs and characteristics of their evaluations affect reading outcomes for students in grades K-12. The review applies consistent inclusion standards to focus on studies that met high methodological standards.…

Syntheses of research on educational programs have taken on increasing policy importance. Procedures for performing such syntheses must therefore produce reliable, unbiased, and meaningful information on the strength of evidence behind each program. Because evaluations of any given program are few in number, syntheses of program evaluations must…

PCI Education conducted a three-year longitudinal study to determine the comparative effectiveness of the "PCI Reading Program" ("PCI") for students with severe disabilities as implemented in Florida's Brevard Public Schools and Miami-Dade County Public Schools. The primary question addressed by the study is whether students…

This article examines theoretical and empirical issues related to the statistical power of impact estimates for experimental evaluations of education programs. The author considers designs where random assignment is conducted at the school, classroom, or student level, and employs a unified analytic framework using statistical methods from the…