An appropriate estimate of statistical power is critical for the design of intervention studies. Although the inclusion of a pretest covariate in the test of the primary outcome can increase statistical power, samples selected on the basis of pretest performance may demonstrate range restriction on the selection measure and other correlated…

This study used multigroup structural equations to evaluate the possibility that a theory-driven, evidence-based, yearlong reading program for sixth-grade struggling readers moderates the interrelationships among elements of the simple model of reading (i.e., listening comprehension, word reading, and reading comprehension; Hoover & Gough,…

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…