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…

The present paper describes the recruitment and site selection process that has been underway since January 2011, with particular emphasis on the use of Mahalanobis distance score to determine matched pairs of sites prior to randomization to treatment and control groups. Through a systematic winnowing process, the authors found that they could…

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…

Supplemental Educational Services (SES), a federally mandated program, is designed to raise student achievement via the implementation of tutoring programs. Unfortunately, although the SES federal legislation has been adopted by school districts nationally, relatively limited empirical evidence from rigorous research studies exists regarding the…