Over the last decade, New York City has been the site of a systemwide high school reform effort that is unprecedented in its scope and pace. Since 2002, the school district has closed more than 20 failing high schools, opened more than 200 new secondary schools, and implemented a centralized high school admission process in which approximately 80,000 students a year indicate their school preferences from a wide-ranging choice of programs. At the heart of these reforms lie the new schools that in this report are called "small schools of choice" (SSCs)--small, academically nonselective, public high schools that were opened between 2002 and 2008. Serving approximately 100 students per grade in grades 9 through 12 and open to students at all levels of academic achievement, the SSCs in this study were created to serve the district's most disadvantaged and historically underserved students. Prior to the 2002-2003 school year, these students would have had little option but to enroll in one of the city's large, zoned high schools when they made the transition from eighth to ninth grade. Many of the large schools were low-performing, with graduation rates below 50 percent. This report presents encouraging findings from an unusually large and rigorous study, supported by the Bill & Melinda Gates Foundation, of the effects of SSCs on students' academic achievement in high school. SSCs have a substantial positive impact on the transition into high school during ninth grade, according to data using all four cohorts: (1) SSC enrollees were 10.8 percentage points more likely than the students who enrolled in other schools to earn 10 or more credits during their first year--73.1 percent compared with 62.3 percent; (2) SSC enrollees were 7.8 percentage points less likely to fail more than one core subject (39 percent compared with 46.8 percent); (3) Combining these two indicators, 58.5 percent of SSC enrollees were on track to graduate in four years compared with 48.5 percent of their counterparts who attended a different type of school--a 10 percentage point difference; and (4) During the first year of high school, SSC enrollees earn almost one full credit more (0.9 credit) toward graduation than do their control group counterparts. These positive effects on the transition into high school during ninth grade were seen among nearly all subgroups as defined by students' academic proficiency, socioeconomic status, race/ethnicity, and gender. For all students, second- and third-year follow-up data indicate that these effects are sustained and/or increased as they continue through high school. For the "first" cohort of students (the only cohort for whom there are four years of follow-up data), the evidence indicates that SSC improvements in students' academic progress and school engagement during the early years of high school translate into higher rates of on-time graduation after four years: (1) SSCs increase overall graduation rates by 6.8 percentage points, from 61.9 percent for students who attend schools other than SSCs to 68.7 percent for SSC enrollees; (2) A majority of the SSC effect on graduation rates reflects an increase in receipt of New York State Regents diplomas. For this type of diploma, students must pass a series of Regents examinations with a score of 65 points or above and pass all of their required courses; and (3) SSCs increase the proportion of students (by 5.3 percentage points) who passed the English Regents with a score of 75 points or higher, the threshold for exempting incoming students at the City University of New York from remedial courses. They did not have an effect on math Regents exams. (Contains 2 tables and 4 footnotes.) [For the full report, "Transforming the High School Experience: How New York City's New Small Schools Are Boosting Student Achievement and Graduation Rates," see ED511106.]