Randomized experiments are often considered the strongest designs to study the impact of educational interventions. Perhaps the most prevalent class of designs used in large scale education experiments is the cluster randomized design in which entire schools are assigned to treatments. In cluster randomized trials (CRTs) that assign schools to…

In this study, differential item functioning (DIF) trends were examined for English language learners (ELLs) versus non-ELL students in third and tenth grades on a large-scale reading assessment. To facilitate the analyses, a meta-analytic DIF technique was employed. The results revealed that items requiring knowledge of words and phrases in…

An early version of this article, discussing curricular interventions in mathematics, was written for the What Works Clearinghouse (WWC). The Institute of Education Sciences (IES), which funds WWC, instructed WWC not to publish it. An expanded version, written at WWC's invitation for a special issue of an independent electronic journal and a book…