Screening risk-averse agents under moral hazard: single-crossing and the CARA case

Principal-agent models of moral hazard have been developed under the assumption that the principal knows the agent's risk-aversion. This paper extends the moral hazard model to the case when the agent's risk-aversion is his private information, so that the model also exhibits adverse selection. We characterize the optimal menu of contracts; while its detailed properties depend on the setting, we show that some of them must hold for all environments. In particular, the power of incentives always decreases with risk-aversion. We also characterize the relationship between the outside option and the optimal contracts. We then apply our results to testing for asymmetric information in insurance markets.The authors thank P.A. Chiappori, D. de Mezza, R. Myerson, C. Prendergast, the late S. Rosen, D. Webb and an anonymous referee for helpful discussions or comments, as well as seminar participants in Berkeley, Chicago, Montré al, Northwestern, Rome, Stanford and Wisconsin. Bruno Jullien gratefully acknowledges financial support from the Fédération Francaise des Sociétés d'Assurance; Bernard Salanié thanks the University of Chicago for its hospitality.