This study evaluated the effectiveness of the Extended-Service Schools (ESS) Initiative, which supported the creation of 60 after school programs in 20 low-income communities nationwide. Each community adapted one of four nationally recognized models that had been successfully developed and implemented in other cities. The models all promoted academic and nonacademic development during out-of-school-hours, involving partnerships between community-based organizations and schools. The evaluation included surveys of school site coordinators and city-level program directors, site visits, and interviews with staff, partners, students, parents, and key city officials. Results indicated that across all sites, programs were put in place fairly quickly, demand for the programs was substantial, and over time, programs matured and demand for their services grew. Programs were well-designed and well-implemented. Participation in the programs was associated with behavior that could help youth stay out of trouble. There were positive effects on school attitudes and behaviors. Costs were reasonable but varied considerably. Operational challenges included funding constraints, staff shortages and retention, and difficulty in creating and implementing approaches for monitoring and assessing program quality. Three appendices include the ESS models, research overview and outcome measures, and the ESS cost study. (Contains 43 references, 12 tables, and 4 figures.)(SM)