An "autorating" (peer rating) system designed to account for individual performance in team projects was used in two sophomore-level chemical engineering courses in which the students did their homework in cooperative learning teams. Team members confidentially rated how well they and each of their teammates fulfilled their responsibilities, the ratings were converted to individual weighting factors, and individual project grades were computed as the product of the team project grade and the weighting factor. Correlations were computed between ratings and grades, self-ratings and ratings from teammates, and ratings received and given by men and women and by ethnic minorities and non-minorities. Incidences of "hitchhikers"...