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 examines the interaction between the fidelity of implementation of a set of research-based strategies--Collaborative Strategic Reading (CSR)--and outcomes for students with mild to moderate disabilities using data from two nonoverlapping studies in middle school language arts and reading classrooms (Study 1) and middle school social…

Collaborative Strategic Reading (CSR) is a multicomponent reading intervention aimed at improving students' text comprehension. Two 1-year randomized controlled trials were conducted to determine the efficacy of CSR with seventh and eighth grade students. The Year 2 replication study was identical to the original Year 1 study except that the…

The purpose of this study was to determine the effects of an early numeracy preventative Tier 2 intervention on the mathematics performance of first-grade students with mathematics difficulties. Researchers used a pretest-posttest control group design with randomized assignment of 139 students to the Tier 2 treatment condition and 65 students to…