Investigating a family intervention approach coordinating psychiatric social work services and development planning by day care center staff, a short-term longitudinal study was made of children and their families from entry into preschool day care through participation in kindergarten and primary grades. Of the 105 preschool children studied, 60 attended the Culver City Children's Center (CCCC) and 45 attended a comparable, geographically distant center that differed from the CCCC in not providing social work services to families. From entry to the 24-month point, daily and at least weekly process data were collected on each family and each child; cross-sectional assessments were also regularly made at the entry point, after 6 weeks, and after 5, 12, and 24 months. Ratings of the child's development were supplemented by various test assessments. Once children were in kindergarten or primary grades, teachers assessed them twice each school year on 16 behavioral ratings. Cross-sectional assessments for the comparison center families and children were made available. Depending on the year of project operation, social workers used psychoanalytically oriented techniques with families in one of three different parent interventions: open-ended, problem-oriented, or consultative with selective use of social work services. Attempts were made to assist children of single working welfare mothers, who were at risk for adapting unsuccessfully to kindergarten. (RH)