In the "individually randomized group treatment" (IRGT) experimental design, individuals are first randomly assigned to a treatment arm or a control arm, but then within each arm, are grouped together (e.g., within classrooms/schools, through shared case managers, in group therapy sessions, through shared doctors, etc.) to receive…

A problem that is frequently encountered during the systematic review process is when studies that meet the inclusion criteria do not provide the appropriate numerical estimates to include in a meta-analysis. For dichotomous outcomes, a method has been suggested by Di Pietrantonj for reconstructing the 2 × 2 table when the Odds Ratio…

Steinberg and Monahan's (2011) reanalysis of the Teen Media longitudinal survey of adolescents does not meet prevailing standards for propensity score analysis and therefore does not undermine the original conclusions of the Brown, L'Engle, Pardun, Guo, Kenneavy, and Jackson (2006) analysis. The media do matter in the sexual socialization of…

This "What Works Clearinghouse Procedures and Standards Handbook (Version 3.0)" provides a detailed description of the standards and procedures of the What Works Clearinghouse (WWC). The remaining chapters of this Handbook are organized to take the reader through the basic steps that the WWC uses to develop a review protocol, identify…

This study empirically investigates the effectiveness of Distributed Leadership Teacher Training (DLT) program on improving student's academic achievement. In addition, it both tests the assumption that the year 1 impacts are stable across calendar years and examines the importance of properly accounting for the fact that the standard error of the…

Parametric analysis of covariance was compared to analysis of covariance with data transformed using ranks. Using a computer simulation approach the two strategies were compared in terms of the proportion of Type I errors made and statistical power when the conditional distribution of errors were: (1) normal and homoscedastic, (2) normal and…

This paper is concerned with the construction of effect size standard errors in situations where the effect sizes are independent but the data have likely been sampled from non-normal distributions, and possibly for different studies, from different families of non-normal distributions. Asymptotic distribution-free estimators are provided for two…