TY - JOUR AU - Einav,Liran AU - Finkelstein,Amy AU - Schrimpf,Paul TI - The Welfare Cost of Asymmetric Information: Evidence from the U.K. Annuity Market JF - National Bureau of Economic Research Working Paper Series VL - No. 13228 PY - 2007 Y2 - July 2007 UR - http://www.nber.org/papers/w13228 L1 - http://www.nber.org/papers/w13228.pdf N1 - Author contact info: Liran Einav Stanford University Department of Economics 579 Serra Mall Stanford, CA 94305-6072 Tel: 650/723-3704 Fax: 650/725-5702 E-Mail: leinav@stanford.edu Amy Finkelstein Department of Economics MIT E52-383B 50 Memorial Drive Cambridge, MA 02142 Tel: 617/253-4149 Fax: 617/868-2742 E-Mail: afink@mit.edu Paul Schrimpf Department of Economics MIT 50 Memorial Drive Cambridge, MA 02142 E-Mail: paul_s@mit.edu AB - Much of the extensive empirical literature on insurance markets has focused on whether adverse selection can be detected. Once detected, however, there has been little attempt to quantify its importance. We start by showing theoretically that the efficiency cost of adverse selection cannot be inferred from reduced form evidence of how "adversely selected" an insurance market appears to be. Instead, an explicit model of insurance contract choice is required. We develop and estimate such a model in the context of the U.K. annuity market. The model allows for private information about risk type (mortality) as well as heterogeneity in preferences over different contract options. We focus on the choice of length of guarantee among individuals who are required to buy annuities. The results suggest that asymmetric information along the guarantee margin reduces welfare relative to a first-best, symmetric information benchmark by about £127 million per year, or about 2 percent of annual premiums. We also find that government mandates, the canonical solution to adverse selection problems, do not necessarily improve on the asymmetric information equilibrium. Depending on the contract mandated, mandates could reduce welfare by as much as £107 million annually, or increase it by as much as £127 million. Since determining which mandates would be welfare improving is empirically difficult, our findings suggest that achieving welfare gains through mandatory social insurance may be harder in practice than simple theory may suggest. ER -