Demonstration of experimental control is considered a hallmark of high-quality single-case research design (SCRD). Studies that fail to demonstrate experimental control may not be published because researchers are unwilling to submit these papers for publication and journals are unlikely to publish negative results (i.e., the file drawer effect).…

The What Works Clearinghouse (WWC) Standards Briefs explain the rules the WWC uses to evaluate the quality of studies for practitioners, researchers, and policymakers. This brief explains what baseline equivalence is and why it matters. As part of the WWC review process for certain types of studies, reviewers assess whether the intervention group…

The "Current Insights" feature is designed to introduce life science educators and researchers to current articles of interest in other social science and education journals. In this installment, I highlight three diverse research studies out of psychology journals that address student study strategies, faculty change, and the influence…

This paper is directed to researchers who conduct and report education intervention studies. Its purpose is to stimulate and guide them to go a step beyond reporting the statistics that emerge from their analysis of the differences between experimental groups on the respective outcome variables. With what is often very minimal additional effort,…

This paper includes a nontechnical description of methods for calculating effect sizes in intellectual and developmental disability studies. Different hypothetical studies are used to illustrate how null hypothesis significance testing (NHST) and effect size findings can result in quite different outcomes and therefore conflicting results. Whereas…

Regression discontinuity designs (RDDs) are considered to be one of the strongest nonexperimental designs available for the purpose of identifying the effects of an intervention. RDD can be used in situations in which assignment to a treatment group is based on a cutoff value on a continuous assignment variable. The impact of the intervention is…

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 methodological brief is designed to provide both program operators and researchers with practical advice about how to assess a program's implementation and impact. Adapted from an article that first appeared in "The Handbook of Youth Mentoring" (DuBois and Karcher, ed. 2005), the brief focuses on the evaluation of mentoring programs, but the…

An evaluation of one therapeutic service offered to sexually abused children in the United Kingdom exposed the methodological issue of false negatives among the comparison group, suggesting that researchers cannot assume that nonreferred comparison subjects have not actually experienced sexual abuse. (DB)

This article examines the status of behavioral research on genetic mental retardation syndromes and finds that the field continues to struggle with three methodological issues: (1) how to think about control or contrast groups, (2) the interplay of behavioral phenotypes with development and other within-group variations, and (3) the efficacy of…

This is a checklist of key items to get right when conducting a randomized controlled trial to evaluate an educational program or practice ("intervention"). It is intended as a practical resource for researchers and sponsors of research, describing items that are often critical to the success of a randomized controlled trial. A significant…