This paper provides practical guidance for researchers who are designing and analyzing studies that randomize schools - which comprise three levels of clustering (students in classrooms in schools) - to measure intervention effects on student academic outcomes when information on the middle...

We explore the use of instrumental variables (IV) analysis with a multisite randomized trial to estimate the effect of a mediating variable on an outcome. We use a random-coefficient IV model that allows both the impact of program assignment on the mediator (compliance with assignment) and the...

The present paper, which is intended for a diverse audience of evaluation researchers, applied social scientists, and research funders, provides a broad overview of the conceptual and statistical issues involved in using multisite randomized trials to learn about and from variation in program...

This paper uses data from the Head Start Impact Study (HSIS), a nationally representative multisite randomized trial, to quantify variation in effects of Head Start during 2002-2003 on children’s cognitive and socio-emotional outcomes relative to the effects of other local alternatives,...

Building on prior research by two of the present authors, which uses lottery-like features in New York City’s high school admissions process to rigorously demonstrate that new small public high schools in the district are markedly improving graduation prospects for disadvantaged students, the...