This article draws on previously employed methods for conducting fidelity studies and applies them to an evaluation of an unprescribed intervention. We document the process of assessing the fidelity of implementation of the Math Recovery first-grade tutoring program, an unprescribed, diagnostic intervention. We describe how we drew on recent…

This article examines changes in the research design, sample size, and precision between the planning phase and implementation phase of group randomized trials (GRTs) funded by the Institute of Education Sciences. Thirty-eight GRTs funded between 2002 and 2006 were examined. Three studies revealed changes in the experimental design. Ten studies…

Applied researchers often find themselves making statistical inferences in settings that would seem to require multiple comparisons adjustments. We challenge the Type I error paradigm that underlies these corrections. Moreover we posit that the problem of multiple comparisons can disappear entirely when viewed from a hierarchical Bayesian…

The authors thank Dr. Lindsay Page for providing a nice illustration of the use of the principal stratification framework to define causal effects, and a Bayesian model for effect estimation. They hope that her well-written article will help expose education researchers to these concepts and methods, and move the field of mediation analysis in…

Principal stratification provides an approach to study the effect of an exposure on an outcome within strata defined by the effect of the exposure on some third, posttreatment, variable (Frangakis & Rubin, 2002). There has been more recent interest in using principal stratification to study the extent to which the effect of an exposure on an…

Experimental evaluations are increasingly common in the U.S. educational policy-research context. Often, in investigations of multifaceted interventions, researchers and policymakers alike are interested in not only "whether" a given intervention impacted an outcome but also "why". What "features" of the intervention led to the impacts observed,…

In this article I review the use of randomized field trials to evaluate school voucher interventions. I argue that although estimates of the effect of the voucher offer on achievement are unbiased in these trials, more specific interpretations such as the effect of attending private school may be difficult to obtain. I discuss several evaluation…

Teacher and principal surveys are among the most common data collection techniques employed in education research. Yet there is remarkably little research on survey methods in education, or about the most cost-effective way to raise response rates among teachers and principals. In an effort to explore various methods for increasing survey response…

In this commentary, the author focuses on the use of design elements for increasing the severity of causal mediation tests. The estimation of causal mediation effects from observational data rests on rather stringent assumptions. In introducing and exemplifying ratio-of-mediator-probability weighting (RMPW), Hong and Nomi (henceforth HN) make…

This article provides practical guidance for researchers who are designing studies that randomize groups to measure the impacts of educational interventions. The article (a) provides new empirical information about the values of parameters that influence the precision of impact estimates (intraclass correlations and R[superscript 2] values) and…

This study examines the reporting of power analyses in the group randomized trials funded by the Institute of Education Sciences from 2002 to 2006. A detailed power analysis provides critical information that allows reviewers to (a) replicate the power analysis and (b) assess whether the parameters used in the power analysis are reasonable.…