This final program evaluation report assessing the University of Western Ontario Preschool Project examined the cognitive and social development of 60 high and low income preschool children to determine whether the program had had a compensatory educational effect on economically disadvantaged children. The data analysis focused on: (1) the children's social competence; (2) their motivational characteristics and cognitive styles; and (3) their intellectual and cognitive abilities. Results showed that the UWO program had been reasonably successful in achieving social development progress and IQ gains with both high and low income children, and that, for the low income children, the program had special compensatory value in the intellectual and cognitive areas. (SE)