The Philadelphia Prekindergarten Head Start program is a child development program for three and four-year-old children from low income families which stresses an interacting and multi-disciplinary attempt to improve the child's physical and emotional health, his family relationships, and his abilities to function better as a person. The program was designed from the beginning to implement five different early childhood educational models (Bank Street, Behavior Analysis, Montessori, Open Classroom, and Responsive Learning). The 1975-1976 evaluation activities for Philadelphia's Prekindergarten Head Start program continued to focus on the major goals for children. There was found to be some range in practices among centers in terms of (1) extent of model implementation, (2) classroom differences within a model, (3) number of parent volunteers, (4) grouping practices, and (5) provisioning. Observation data yielding the above information are summarized according to model and across the total program. The Denver Developmental Screening Test (D.D.S.T.) was administered during October and April to 82% and 84% of the population respectively. In April only 1.8% of the population was identified as having a developmental delay as defined by the D.D.S.T., a decrease of about 40% from the Fall administration. While Prekindergarten Head Start children are from families of low socio-economic status, the April D.D.S.T. results confirmed, as was the case in 1974-1975, that the population screened had improved after a year of program participation so that there were far fewer children "at risk" than were found in the norming population. (Author/MV)