This executive summary presents the major results of the longitudinal evaluation of Project Developmental Continuity (PDC). A Head Start demonstration project initiated by the Administration for Children, Youth and Families (ACYF) in 1974, the PDC aimed to stimulate the development and implementation of comprehensive programs linking Head Start centers with local elementary schools in order to provide continuous developmental support through the third grade for children from low-income families. Full-fledged implementation of PDC programs began in 1976 at 13 sites distributed across the Head Start regions and the Indian and Migrant Program Division. Findings of the evaluation suggest that (1) the program model intended by ACYF was not fully realized anywhere, (2) local versions of PDC had few effects on parents and teachers that were likely to enhance children's social competence, and (3) children's social competence was not generally enhanced by their program participation. In conclusion, reasons the evaluation failed to demonstrate PDC's effectiveness are explored. (RH)