The increasing trend of placing students with disabilities in general education classrooms has raised questions among researchers, policymakers, practitioners, and parents about classmate peer effects on all students. However, little is known about the peer effects of classmates with disabilities on the outcomes of other students in the classroom;…

In this invited response to Moe and Anzia (2014), we describe both the points of convergence and divergence between our prior research (2007a, 2007b) and that of Moe (2005) and Moe and Anzia (2014). We also respond to Moe and Anzia's critique of our published work. Moe and Anzia's study helps to refine the policy discussion around…

In this article, the authors Sarah A. Anzia and Terry M. Moe, offer a retort to William S. Koski and Elieen L. Horng's argument that their study of seniority-based transfer rules is narrow and that its findings only apply under limited circumstances. The Koski-Horng's study, by contrast, takes a broad frame--so broad that, as detailed in…

We contribute to debate about causal inferences in educational research in two ways. First, we quantify how much bias there must be in an estimate to invalidate an inference. Second, we utilize Rubin's causal model to interpret the bias necessary to invalidate an inference in terms of sample replacement. We apply our analysis to an inference…

This paper provides practical guidance for researchers who are designing and analyzing studies that randomize schools--which comprise three levels of clustering (students in classrooms in schools)--to measure intervention effects on student academic outcomes when information on the middle level (classrooms) is missing. This situation arises…

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…

The present meta-analysis examines the effect of grade retention on academic outcomes and investigates systemic sources of variability in effect sizes. Using multilevel modeling (MLM), the authors investigate characteristics of 207 effect sizes across 22 studies published between 1990 and 2007 at two levels: the study (between) and individual…

Research in fields other than education has found that studies with small sample sizes tend to have larger effect sizes than those with large samples. This article examines the relationship between sample size and effect size in education. It analyzes data from 185 studies of elementary and secondary mathematics programs that met the standards of…

Adjustment methods such as propensity scores and analysis of covariance are often used for estimating treatment effects in nonexperimental data. Shadish, Clark, and Steiner used a within-study comparison to test how well these adjustments work in practice. They randomly assigned participating students to a randomized or nonrandomized experiment.…

The influence of teachers' qualifications on their teaching practice has been subject to debate. Literature reviews do not settle these debates, partly because the literature is uneven and partly because reviews capture only narrow slices of literature. In particular, many reviews eliminate qualitative studies. Yet without examining qualitative…

This article summarizes the findings of the National Research Council (NRC) report "On Evaluating Curricular Effectiveness" and examines the reviews in middle grades mathematics undertaken by the What Works Clearinghouse (WWC). The NRC report reviewed and assessed 147 key evaluations of 13 National Science Foundation-supported K-12 mathematics…

Utilizing the regression-discontinuity research design, this article explores the effectiveness of a developmental English program in a large, multicampus community college. Routinely collected data were extracted from existing records of a cohort of first-time college students followed for approximately 6 years (N = 1,473). Results are consistent…

This article presents the results of an 11-year longitudinal study of the impact of America's Choice comprehensive school reform (CSR) design on student learning gains in Rochester, New York. A quasi-experimental interrupted time-series approach using Bayesian hierarchical growth curve analysis with crossed random effects is used to compare the…

Discusses reasons randomized experiments in educational research have been so rare and appraises alternatives to experiments that educational evaluators prefer. These alternatives are found wanting whenever a high standard is needed for justifying causal conclusions. (SLD)