This article provides practical guidance for researchers who are designing studies that randomize groups to measure the impacts of educational interventions. The article (a) provides new empirical information about the values of parameters that influence the precision of impact estimates (intraclass correlations and R[superscript 2] values) and…

This guide is designed as a resource for leaders and evaluators of K-12 online learning programs. In this guide, the term "online learning" is used to refer to a range of education programs and resources in the K-12 arena, including distance learning courses offered by universities, private providers, or teachers at other schools;…

Social promotion has long been the normal practice in American schools. Critics of this practice, whereby students are promoted to the next grade regardless of academic preparation, have suggested that students would benefit academically if they were made to repeat a grade. Supporters of social promotion claim that retaining students disrupts them…