国有土地拍卖机制研究

本文基于贝叶斯均衡上的执行问题,讨论了参与人参数环境空间受机制设计者影响时,不同机制选择的执行条件,给出了目标函数不变时机制对偶等价性的充分必要条件。并比较了中国国有土地拍卖三大机制的效率,给出了土地拍卖机制在实话实说可执行下对的社会福利影响,研究发现：当参与者可以策略性选择行动,实现政府利益最大时,选择限房价或者限地价机制是等价的;非市场机制和市场机制相比,关键还是土地财政和消费者利益之间的权衡;实话实说可执行机制直接显示了政府利益、开发商利润与消费者利益三者之间的权衡关系,但并未改进社会福利。     

On the Equivalence of Bayesian and Dominant Strategy Implementation

We consider a standard social choice environment with linear utilities and independent, one‐dimensional, private types. We prove that for any Bayesian incentive compatible mechanism there exists an equivalent dominant strategy incentive compatible mechanism that delivers the same interim expected utilities for all agents and the same ex ante expected social surplus. The short proof is based on an extension of an elegant result due to Gutmann, Kemperman, Reeds, and Shepp (1991). We also show that the equivalence between Bayesian and dominant strategy implementation generally breaks down when the main assumptions underlying the social choice model are relaxed or when the equivalence concept is strengthened to apply to interim expected allocations.     

工艺设计质量信息不对称环境下质量激励合同设计

工艺设计质量决定了产品可制造性,从而对产品质量产生重要影响。在生产外包环境下,不仅供应商的质量努力难以合同化,而且工艺设计质量可能是设计者的私人信息,因此在供应商和制造商之间往往是不对称的,从而为质量激励合同设计带来挑战。本文考虑一个制造商和一个供应商构成的两级供应链。制造商可能自己设计产品,然后将生产外包给供应商,也可能将设计和生产都外包给供应商。本文分析了在这两种外包策略下,制造商的质量激励合同设计。研究发现：1）当工艺设计质量是对称信息时,制造商可以通过质量合同设计实现全局最优质量和利润;2）当工艺设计质量是制造商的私人信息时,工艺设计质量高的制造商可以通过降低对供应商的质量惩罚强度以及增加采购价格来传递工艺设计质量的信号;3）当工艺设计质量是供应商的私人信息时,制造商可以通过质量合同菜单来甄别工艺设计质量信息。与工艺设计质量是对称信息时的均衡合同相比,在针对低工艺设计水平供应商的合同中,制造商降低质量惩罚强度和采购价格;在针对高工艺设计水平供应商的合同中,质量惩罚强度不变,但采购价格提高。     

土地使用权机制的实现与执行

机制设计者的目的是想最优化一个基于环境参数空间的社会福利函数,但是有关环境参数的相关信息分散于经济之中,因此机制设计者既想收集尽可能多的相关信息,又想充分利用这些信息制定一个社会决策。机制通常在两个框架下讨论,分为实现和执行,两者本质区别在于后者利用了对策性思维方式。本文给出了土地使用权机制在二维信息传递空间下的实现问题,将激励相容条件引入信息有效的机制实现中,给出了占优均衡下的机制执行。研究发现:在实话实说假设下,能够降低信息传递空间维度,并且通过一个信息有效的机制来实现政府目标函数;参与人能够利用私有信息时,实话实说不能成为一个纳什均衡,但在占优均衡下可以通过机制来执行。     

Robust Mechanism Design

The mechanism design literature assumes too much common knowledge of the environment among the players and planner. We relax this assumption by studying mechanism design on richer type spaces. We ask when ex post implementation is equivalent to interim (or Bayesian) implementation for all possible type spaces. The equivalence holds in the case of separable environments; examples of separable environments arise (1) when the planner is implementing a social choice function (not correspondence) and (2) in a quasilinear environment with no restrictions on transfers. The equivalence fails in general, including in some quasilinear environments with budget balance. In private value environments, ex post implementation is equivalent to dominant strategies implementation. The private value versions of our results offer new insights into the relationship between dominant strategy implementation and Bayesian implementation.     

The Dynamic Pivot Mechanism

We consider truthful implementation of the socially efficient allocation in an independent private‐value environment in which agents receive private information over time. We propose a suitable generalization of the pivot mechanism, based on the marginal contribution of each agent. In the dynamic pivot mechanism, the ex post incentive and ex post participation constraints are satisfied for all agents after all histories. In an environment with diverse preferences it is the unique mechanism satisfying ex post incentive, ex post participation, and efficient exit conditions. We develop the dynamic pivot mechanism in detail for a repeated auction of a single object in which each bidder learns over time her true valuation of the object. The dynamic pivot mechanism here is equivalent to a modified second price auction.     

Bayesian and Dominant‐Strategy Implementation in the Independent Private‐Values Model

We prove—in the standard independent private‐values model—that the outcome, in terms of interim expected probabilities of trade and interim expected transfers, of any Bayesian mechanism can also be obtained with a dominant‐strategy mechanism.     

An Efficient Dynamic Mechanism

This paper constructs an efficient, budget‐balanced, Bayesian incentive‐compatible mechanism for a general dynamic environment with quasilinear payoffs in which agents observe private information and decisions are made over countably many periods. First, under the assumption of “private values” (other agents' private information does not directly affect an agent's payoffs), we construct an efficient, ex post incentive‐compatible mechanism, which is not budget‐balanced. Second, under the assumption of “independent types” (the distribution of each agent's private information is not directly affected by other agents' private information), we show how the budget can be balanced without compromising agents' incentives. Finally, we show that the mechanism can be made self‐enforcing when agents are sufficiently patient and the induced stochastic process over types is an ergodic finite Markov chain.