Peer evaluation: incentives and co-worker relations

In many workplaces, coworkers have the best information about each other's efforts. This paper studies a principal who only observes the joint output by two limitedly liable agents, while agents receive signals about each other's effort levels. The principal attempts to exploit this information through peer evaluation; agents are asked to report their signal and may receive a bonus for being evaluated positively. Lying aversion ascertains that truthful evaluation is possible, while interpersonal relations between colleagues give an incentive to misreport. This paper shows that peer evaluation gives an incentive for effort, even when the evaluations are not truthful. The peer evaluation bonus is constrained by more intensive coworker relations. Still, the optimal contract always includes a peer evaluation bonus, sometimes complemented with a team bonus. Coworker relations have nonmonotonic effects on profits in the optimal contract.