Some Economic Consequences of Adverse Selection

交易的一方通常知道一些与交易相关而另一方不知道的事情。这种信息不对称在经济活动中普遍存在：例如，在雇主与雇员之间的关系中，雇员的努力无法得到完美的监控；保险人与被保险人之间；股东与公司经理之间的协议；在社会主义企业和中央计划经济之间；或者当物品的价值不确定时，在买方和卖方之间。这种情况被称为逆向选择，因为信息的不对称会导致低效的结果。这个项目为逆向选择的一些困难和尚未解决的方面提供了新的见解。该项目由五个部分组成。首先，它描述了在逆向选择（每个团队成员的能力只有他自己知道）和道德风险（无法观察到的努力）存在的情况下，团队成员的合同的特征。初步结果表明，可以设计一个不需要监控的最优契约来防止团队成员的逃避。当一些关键的简化假设被放宽时，进一步的研究确定了结果。其次，它分析了竞标者环，即竞标者在重复拍卖中，在竞标者能够或不能够相互转让时串通的努力。竞标者必须克服不知道对方对该物品的价值的不对称信息问题。第三，项目决定了销售具有无人知晓的明确价值的独特物品（如采矿权）的最佳方式。第四，研究分散信息获取的拍卖。大多数拍卖理论假设信息是固定的，但在实践中，竞标者可以获得更昂贵的信息。例如，在矿业权竞标中，可以进行地质调查。第五，该项目使用拍卖理论中开发的工具来模拟证券市场价格形成过程。特定的市场机构，如经销市场和结算所的影响是确定的。

One party to an exchange often knows something relevant to the transaction that the other party does not know. Such asymmetries of information are pervasive in economic activity: for example, in the relationship between employer and employee when the employee's effort cannot be monitored perfectly; between insurer and insured; between the stockholders and the manager of a firm; between a socialist firm and the central planner; or between buyer and seller when the value of the item is uncertain. This situation is called adverse selection because the asymmetries of information can lead to inefficient outcomes. This project provides new insights into a number of difficult and as yet unresolved aspects of adverse selection. The project consists of five parts. First, it characterizes contracts for members of a team in the presence of both adverse selection (each team member's ability is known only to himself) and moral hazard (effort cannot be observed). Preliminary results show that an optimal contract can be designed in which monitoring is not needed to prevent shirking by team members. Further research determines the results when a number of crucial simplifying assumptions are relaxed. Second, it analyzes bidder rings, the efforts of bidders at repeat auctions to collude when bidders either can or cannot make transfers among themselves. Bidders must overcome the asymmetric-information problem of not knowing how much each other values the item. Third, the project determines the best way of selling a unique item with a well- defined value which no one knows (like mineral rights). Fourth, the project studies auctions with decentralized information acquisition. Most auction theory assumes that information is fixed, but, in practice, bidders can acquire more costly information. For example, in mineral-rights bidding, geological surveys can be done. Fifth, the project uses the tools developed in auction theory to model the securities-market price-formation process. The effects of particular market institutions like the dealership market and the clearing house are determined.