Money-Back Contracts with Double Moral Hazard
分析卖家承诺退货时按比例退款的三阶段博弈合同，在双重道德风险下起到激励作用，发现适度不确定性下存在有效合同，不确定性过低或过高则导致效率损失。
We analyze money-back contracts, in which a seller promises to refund some fraction of the buyer's purchase price if an item is returned, as a three-stage game. In a cooperative first stage the players determine a price and refund share. In the second stage they noncooperatively choose inputs. The buyer decides whether to return the item in the final stage. This process economizes on the information necessary to enforce a contract and serves an incentive function when transactions involve double moral hazard. Efficient contracts exist when uncertainty is moderate. Inefficiencies result when there is either insufficient or excessive uncertainty.