Multisite trials can clarify the average impact of a new program and the heterogeneity of impacts across sites. Unfortunately, in many applications, compliance with treatment assignment is imperfect. For these applications, we propose an instrumental variable (IV) model with person-specific and site-specific random coefficients. Site-specific IV…

This article presents the authors' rejoinder to the comments of Howard Bloom, Derek Neal, and Mike Seltzer on their article. Their commentary focused foremost on the advantages and disadvantages of using Options A, B, or C in using instrumental variables in multisite trials. Of interest are the quantities one can estimate and test in each case,…

A dramatic shift in research priorities has recently produced a large number of ambitious randomized trials in K-12 education. In most cases, the aim is to improve student academic learning by improving classroom instruction. Embedded in these studies are theories about how the quality of classroom must improve if these interventions are to…