The effect of teammate personality on team production

Many goods and services are produced in teams. We explore how teammate personality traits impact productiv-ity on joint team tasks. Studying student teams at a large university and considering the "Big Five " personality characteristics of extroversion, agreeableness, conscientiousness, emotional stability, and openness, we find that teammate conscientiousness has a small, positive impact on team performance: a one standard deviation in-crease in teammate conscientiousness increases performance on a team task by about three percent of a standard deviation in our preferred specification. The effect is evident holding teammate ability and gender fixed, and suggestively operates through improved team functioning and sustained increases in student effort. We also find evidence of positive spillovers from teammate openness and negative spillovers from teammate extroversion.