The study reviewed in this paper examined whether winning an admissions lottery to attend a small school of choice (SSC) in New York City improved high school graduation rates, influenced the type of diploma students received, or increased the likelihood of college readiness. An SSC is a small, nonselective public high school emphasizing academic rigor, strong relationships between students and teachers, and community partnerships. Researchers analyzed data on more than 12,130 students who participated in ninth-grade admissions lotteries for 84 SSCs in New York City (from an initial sample of 14,969 students in lotteries for 84 SSCs). The study included three cohorts of first-time ninth graders who participated in lotteries for SSC admission during the 2004-05, 2005-06, or 2006-07 school years, and each cohort was followed for 4 years. The study authors found, and the What Works Clearinghouse (WWC) confirmed, that an offer of admission to an SSC increased 4-year graduation rates (in particular, increases in rates of receiving a Regents diploma) and college readiness in English, but had no effect on college readiness in math or other types of high school diplomas that students received. The research described in this report is a well-executed randomized controlled trial and meets WWC evidence standards without reservations. Four appendices include: (1) Study details; (2) Outcome measures for each domain; (3) Study findings for each domain; and (4) Supplemental findings by domain. A glossary of terms is also included. [The following study is the focus of this "Single Study Review": Bloom, H., & Unterman, R. (2013). "Sustained progress: New findings about the effectiveness and operation of small public high schools of choice in New York City." New York: MDRC.]