When cluster randomized experiments are analyzed as if units were independent, test statistics for treatment effects can be anticonservative. Hedges proposed a correction for such tests by scaling them to control their Type I error rate. This article generalizes the Hedges correction from a posttest-only experimental design to more common designs…

Reading Recovery is one of the most researched literacy programs worldwide. Although there have been at least 4 quantitative reviews of its effectiveness, none have considered all rigorous group-comparison studies from all implementing nations from the late 1970s to 2015. Using a hierarchical linear modeling (HLM) v-known analysis, we examined if…

In a recently published meta-analysis, Tran, Sanchez, Arellano, and Swanson (2011) synthesized 13 studies that permitted assessment of characteristics of children who were adequate and inadequate responders to instruction. The authors indicated that "[t]he central question addressed in this review is whether individual differences in…