Eight Head Start centers which used the Responsive Model program during the 1968-69 school year were assessed to determine cognitive development of children, teacher performance in the classroom, adequacy of physical facilities, administrative support and the interrelationship between these variables. Teachers were observed at the beginning and end of the school year and rated on a scale designed to indicate the degree to which they implemented the procedures of the Responsive Model. Findings indicated that the majority of teachers increased their teaching skills and became more consistent with the Model criteria. The Preschool Inventory (PSI) measuring achievement in skills and concepts, was administered on a pre-post basis to 761 children, and average scores in all eight communities demonstrated growth throughout the year. Year-end scores for the Responsive Model children were at national norm levels reported for middle class children. (A limitation of the PSI is its less than adequate norms.) Changes in child test performance were greatest in classrooms with adequate physical facilities, in situations with few administrative problems and where teacher performance was consistent with Responsive Model Objectives. When measured by PSI changes, child growth was greatest for those in classes whose teachers demonstrated a high level of teaching ability. (Author/NH)