This article presents 3 standardized effect size measures to use when sharing results of an analysis of mediation of treatment effects for cluster-randomized trials. The authors discuss 3 examples of mediation analysis (upper-level mediation, cross-level mediation, and cross-level mediation with a contextual effect) with demonstration of the…

The regression discontinuity design (RDD) has the potential to yield findings with causal validity approaching that of the randomized controlled trial (RCT). However, Schochet (2008a) estimated that, on average, an RDD study of an education intervention would need to include three to four times as many schools or students as an RCT to produce…

Objective: Examine the influence of altering the size of snack food (ie, small vs large cookies) on short-term energy intake. Methods: First- and sixth-graders (n = 77) participated in a between-subjects experimental design. All participants were offered the same gram weight of cookies during an afternoon tea at their school. For half of the…

This report describes a cluster randomized control trial (RCT) intervention study of the effectiveness of the ABRACADABRA (ABRA) Web-based literacy system using a classroom-level RCT intervention with 1,067 children in 74 kindergarten and Grade 1 or Grade 1/2 classrooms across Canada. The authors closely followed the CONSORT criteria for executing…

Despite impressive advances in the science of reading intervention, how to best help at-risk readers remains a point of contention. Because reading represents the synthesis of background factors and language and reading skills--all of which develop with age and experience--this meta-analysis investigated whether development (as approximated by…

Using a cluster randomization design, schools were randomly assigned to implement Success for All, a comprehensive reading reform model, or control methods. This article reports final literacy outcomes for a 3-year longitudinal sample of children who participated in the treatment or control condition from kindergarten through second grade and a…