New York City Small Schools of Choice Evaluation
Last registered on February 14, 2017


Trial Information
General Information
New York City Small Schools of Choice Evaluation
Initial registration date
February 06, 2017
Last updated
February 14, 2017 2:49 PM EST

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Additional Trial Information
On going
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Secondary IDs
The New York City public school system is the largest in the United States, with over 1,200 schools and more than 1.1 million students enrolled each year. For more than a decade, it has also been the site of an unprecedented investment in high school reform. Beginning in 2002 and with the support of the Bill & Melinda Gates Foundation and other philanthropies, the New York City Department of Education (NYCDOE) closed many large, comprehensive high schools with a history of low performance and created hundreds of new small secondary schools. At the same time, the NYCDOE instituted a centralized high school admissions process for matching incoming ninth-grade students to the over 400 high school options available to them.

The small-school movement has been a national one. And while nearly every major American urban district has undertaken efforts to create new small schools or to transform large schools into campuses of small learning communities, there has been little rigorous evidence about the effectiveness of small schools.

New York City uses a lottery-like system to assign students when the high schools they choose are oversubscribed. MDRC has been able to take advantage of that system to develop an unusually large and rigorous study of the impact of these small high schools on students’ academic achievement, high school graduation, and progression into college. The project’s reports and policy briefs provide rigorous evidence that new small public high schools are narrowing the educational attainment gap and markedly improve graduation prospects, particularly for disadvantaged students.
Registration Citation
Bloom, Howard and Rebecca Unterman. 2017. "New York City Small Schools of Choice Evaluation." AEA RCT Registry. February 14.
Experimental Details
New York City's new small high schools--called Small Schools of Choice (SSCs) in this project--are more than just small. They were authorized through a demanding, competitive proposal process designed to attract innovative ideas for new schools from a range of stakeholders and institutions, from educators to school reform intermediary organizations. The resulting schools emphasize strong, sustained relationships between students and faculty. Each SSC also received start-up funding as well as assistance and policy support from the district and other key players to facilitate leadership development, hiring, and implementation.

While the new small schools in New York City have a wide variety of themes and educational philosophies, they are intended to share three common design characteristics:

-- Academic rigor: Schools are expected to be college preparatory in that they move all students toward acquisition of a New York Regents Diploma.
-- Personalization: Schools were to be small not only in size but also in function to ensure strong student-teacher relationships and to hold adults accountable for individual student outcomes.
-- Community partnerships: Through partnerships with business and community partners, schools were intended to offer learning opportunities outside of the classroom and to infuse relevant real-world examples into classroom instruction. Partners were expected to bolster school capacity in areas ranging from curriculum and instruction to youth development and community outreach.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
high school enrollment, attendance, course credits earned, state exam scores, postsecondary enrollment, postsecondary completion
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
The impact study capitalizes on random elements of the NYCDOE's centralized high school admissions process. Each lottery for a small school of choice is a naturally occurring experiment, which, after some adjustments, makes it possible to produce valid estimates of the effects of enrollment in SSCs on student academic outcomes. The impact study follows four cohorts of students--those entering high school in the fall of 2005, 2006, 2007, and 2008. The primary sources of data for the analyses are High School Application Processing System (HSAPS) data and school records, which were obtained from the NYCDOE.

Because about 7% of SSC lottery winners do not enroll in an SSC and about 35% of those who lose a particular SSC lottery enroll in a different SSC (whether through HSAPS assignment or otherwise), the contrast between the two groups is diluted. Therefore the estimated effects of winning an SSC lottery are converted into the estimated effects of enrolling in an SSC by means of instrumental variables analysis. For details, see Howard Bloom, Saskia Levy Thompson, and Rebecca Unterman, "Transforming the High School Experience: How New York City’s New Small Schools Are Boosting Student Achievement and Graduation Rates" (New York: MDRC, 2010), at

The MDRC school characteristics study uses extant data from the U.S. Department of Education, New York State Report Card, and NYCDOE, along with aggregate HSAPS and student records data in a school-level database, to analyze changes in high school options and student enrollment over time. The analyses identify patterns and trends among schools for a number of instruction-related, demographic, and performance-based characteristics by school type as defined by size and selectivity.
Experimental Design Details
Not available
Randomization Method
School lottery
Randomization Unit
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
Sample size: planned number of observations
30,959 student observations (21,085 students)
Sample size (or number of clusters) by treatment arms
17,981 student observations in the control group; 12,978 student observations in the SSC lottery winner group
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
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IRB Approval Date
IRB Approval Number