Understanding how heterogeneity in peer group composition affects academic attainment has important implications for how schools organize students in group settings. The random assignment of cadets to companies at West Point affords an opportunity to investigate this issue empirically. Estimates...

This paper uses random assignment in professional golf tournaments to test for peer effects in the workplace. We find no evidence that playing partners' ability affects performance, contrary to recent evidence on peer effects in the workplace from laboratory experiments, grocery scanners, and...