Many states and school districts are implementing test-based requirements for promotion at key transitional points in students' schooling careers, thus ending the practice of "social promotion"--promoting students who have failed to meet academic standards and requirements for that grade. In 2003-2004, the New York City Department of Education (NYCDOE), which oversees the largest public school system in the country, implemented a new test-based promotion policy for 3rd-grade students and later extended it to 5th, 7th, and 8th graders. The policy emphasized early identification of children at risk of being retained in grade and provision of instructional support services to these students. NYCDOE asked RAND to conduct an independent longitudinal evaluation of the 5th-grade promotion policy and to examine the outcomes for two cohorts of 3rd-grade students. The findings of that study, conducted between March 2006 and August 2009, provide a comprehensive picture of how the policy was implemented and factors affecting implementation; the impact of the policy on student academic and socioemotional outcomes; and the links between the policy's implementation and the outcomes of at-risk students. This report is organized into eleven chapters: (1) Introduction (Sheila Nataraj Kirby, Jennifer Sloan McCombs, and Louis T. Mariano); (2) What We Know About the Effects of Grade Retention and Implementation of Promotion Policies (Nailing Xia and Sheila Nataraj Kirby); (3) Context and Conceptual Framework for Understanding New York City's Promotion Policy (Jennifer Sloan McCombs, Sheila Nataraj Kirby, Julie A. Marsh, and Catherine DiMartino); (4) Data and Methods (Sheila Nataraj Kirby, Louis T. Mariano, and Jennifer Sloan McCombs); (5) School-Provided Support for Students: Academic Intervention Services (Jennifer Sloan McCombs, Scott Naftel, Gina Schuyler Ikemoto, Catherine DiMartino, and Daniel Gershwin); (6) Implementation of the Policy: Saturday and Summer Schools (Gina Schuyler Ikemoto, Jennifer Sloan McCombs, Catherine DiMartino, and Scott Naftel); (7) Performance of 5th Graders in New York City and Overall Performance Trends in New York State (Sheila Nataraj Kirby, Scott Naftel, Jennifer Sloan McCombs, Daniel Gershwin, and Al Crego); (8) Measuring the Effect of Supportive Interventions on Proximal-Year Student Achievement (Louis T. Mariano, Sheila Nataraj Kirby, Al Crego, and Claude Messan Setodji); (9) Future Outcomes of Students at Risk of Retention (Louis T. Mariano, Sheila Nataraj Kirby, and Al Crego); (10) The Impact of New York City's Promotion Policy on Students' Socioemotional Status (Vi-Nhuan Le, Louis T. Mariano, and Al Crego); and (11) Conclusions and Policy Implications (Sheila Nataraj Kirby, Jennifer Sloan McCombs, and Louis T. Mariano). Appended are: (1) Technical Appendix for Achievement Models; (2) Supporting Data for Chapter Five; (3) Supporting Data for Chapter Seven; (4) Supporting Data for Chapter Ten; and (5) Data and Analyses for 3rd-Grade Cohorts. (Contains 59 figures and 77 tables.)