The San Francisco Beacon Initiative (SFBI) has been in effect in the San Francisco Unified School District since 1996. A collaboration of public and private funders, SFBI operates comprehensive after-school programs in six middle schools, one elementary school and one high school. Public/Private Ventures' (P/PV's) evaluation found that SFBI programs consisted of high quality after-school activities, provided young people with important developmental experiences (such as adult support) and prevented declines in school effort (typical among middle school youth). Although the initiative did not explicitly set out to improve young people's academic outcomes, these were also examined. Despite the high quality of the centers' developmental programs, participants showed no academic gains, and the authors conclude that positive developmental experiences are not sufficient for ensuring academic success among youth who are already struggling in school. This report contains nine chapters, structured according to the theory of change. Following an introduction, Chapter 2 describes the theory of change in more detail. Chapter 3 describes the initiative as a whole, and Chapter 4 describes the centers and asks whether or not they achieved key early outcomes. Chapters 5 through 8 are the heart of this report. Chapter 5 examines the quality of the programming at the centers and the organizational and staff practices that contributed to high-quality programs. Chapter 6 analyzes youth participation at the centers. It also examines center and programmatic characteristics that might be linked to participation. Chapters 7 and 8 look at young people's outcomes. Chapter 7 examines the developmental experiences that young people had at the centers and whether or not those experiences can be linked to participation. Chapter 8 examines long-term outcomes--competency development, social well-being and school success. Chapter 9, the conclusion, reflects on the implications that the findings have for the after-school field. Appended to this report are: (1) Methodology: Data Sources; (2) Overview of the Relationships between Developmental Experiences and Youth Outcomes; (3) More Detailed Tables of Explanation to Accompany Findings Reported in Chapter 4; (4) Analyses Conducted for Presentation in Chapter 5; (5) Response Rates, Measures and Measure Development; (6) Analysis for Chapter 6: Predicting Participation Based on Quantitative Data; and (7) Analysis Strategy for Examining Change in Developmental Experiences Presented in Chapter 7 and for the Path Models Presented in Chapter 8: Assessing the Youth Development Model and the Relationship of Beacon Participation to Long-Term Outcomes. (Contains 50 tables, 12 figures, and 60 endnotes.) [This publication was produced with the Stanford University School of Education Research Team. Additional funding for this research was provided by the Evelyn & Walter Haas, Jr. Fund.]