PROJECT SUMMARY/ABSTRACT A major goal of publicly funded early childhood education (ECE) programs for low-income families is to address underlying social disparities in order to improve children's long-term educational attainment and health outcomes. Rates of participation in ECE programs and public investment in these programs have grown dramatically over the last 30 years, changing the context for understanding the potential long-term program benefits. Whereas existing long-term studies (Perry Preschool, Abecedarian) compared the benefits of ECE versus home care, the critical question facing ECE programs today is whether improvements in the quality of contemporary ECE programming can have incremental long-term benefits. In order to optimize return on investment, long-term studies evaluating costs and benefits of ECE program enhancements are needed. The proposed study will examine the long-term outcomes and identify the public service and financial costs affected by the two REDI interventions, enhancements to the Head Start classroom and home visit programming respectively, and estimate their likely return on investment. We propose interviews with and administrative data collection for participants in each of two ongoing longitudinal studies, the REDI-Classroom (REDI-C) trial (n=356, retention=80%) and the REDI-Parent (REDI-P) trial (n=200, retention=86%), that have followed children with detailed measurement of adaptive social-emotional and academic functioning from preschool into adolescence. There are three aims: 1) Assess the long-term impact of REDI programs with follow-up assessments that extend to early adulthood (age 23) for participants in the classroom program and through high school completion (age 19) for participants in the parent program; 2) Collect new services and administrative data from education, criminal justice, healthcare, and social service records to estimate the costs linked to program effects and determine the long-term return on investment for the REDI-C and REDI-P programs; and 3) explore the associations between initial REDI-C and REDI-P impacts on social-emotional/ self-regulation skills and later, long-term benefits, and explore possible moderation of intervention effects by the quality of the school contexts experienced by participants in order to illuminate likely mechanisms of action and inform future ECE intervention design.