A return potential measure of setting norms for aggression.

This study tested a classroom-level measure of norms based on J. Jackson's (1966) Return Potential Model. "Return potential" refers to the probability of approval of aggression in a given setting or group, and the return potential model allows quantification of different aspects of a setting's norms. Return potential measures were computed for unprovoked and provoked aggression. A pilot sample of 236 students in 11 classrooms and a main sample of 3,304 students in 158 classrooms completed this measure and a self-report measure of aggression. Results from hierarchical linear models showed that all measures of classroom return potential for aggression were significantly clustered by classrooms. Four return potential measures had main effects on aggression, and four measures showed variation in effects by grade or urban residence. Differences in clustering and effects by grade suggested age differences in the importance of different normative characteristics.