This paper provides rigorous evidence (for 12,130 participants in a series of naturally occurring randomized lotteries) that a large‐scale high school reform initiative (New York City's creation of 100+ small high schools of choice between 2002 and 2008) can markedly and consistently increase...

Evaluations of public programs in many fields reveal that different types of programs—or different versions of the same program—vary in their effectiveness. Moreover, a program that is effective for one group of people might not be effective for other groups, and a program that is effective...

Bloom presents findings from the Texas Worker Adjustment Demonstration, a 2,192-person randomized experimental evaluation of reemployment programs for displaced workers conducted at three sites in Texas. This project demonstrated that a relatively inexpensive mix of job-search assistance and...

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...

Evaluations of public programs in many fields reveal that (1) different types of programs (or different versions of the same program) vary in their effectiveness, (2) a program that is effective for one group of people might not be effective for other groups of people, and (3) a program that is...