In this paper we show that sorting di¤erent ability contestants in piece rate tournaments into more homogenous groups alters incentives for agents to exert e¤ort. In particular we show that for a given mean of the tournament group's ability parameters, larger variance (more heterogenous agents) induces higher optimal e¤ort. This implies We thank Chuck Knoeber, Jingfeng Lu, Wally Thurman, Fanis Tsoulouhas, participants of the conference "Tournaments, Contests and