Balanced Bayesian mechanisms

In the transferable utility case, a number of authors have identified conditions on beliefs that guarantee the existence of Bayesian incentive compatible mechanisms with balanced transfers. We present a new, easy to interpret, condition and we show that it is (strictly) more general than all the other conditions found in the literature. We also study conditions guaranteeing the Bayesian implementability of all social decision rules with balanced budget mechanisms.     

A characterization of efficient, bayesian incentive compatible mechanisms

Summary. A mechanism that is both efficient and incentive compatible in the Bayesian-Nash sense is shown to be payoff-equivalent to a Groves mechanism at the point in time when each agent has just acquired his private information. This equivalence result simplifies the question of whether or not an efficient, Bayesian incentive compatible mechanism can satisfy other desired objectives, for the search for an appropriate mechanism can be restricted to the family of Groves mechanisms. The method is used to extend the result of Myerson and Satterthwaite on the inefficiency of bilateral bargaining to a multilateral setting. Received: June 30, 1997; revised version: May 22, 1998     

Agreeing on Efficient Emissions Reduction

We propose a simple contest‐based mechanism providing incentives to reduce harmful emissions to their efficient level without infringing upon productive efficiency. Participation in the most stylized form of the scheme is voluntary and individually rational; all rules are mutually agreeable and are unanimously adopted if proposed. The scheme balances its budget and requires no principal. In a perhaps more realistic stochastic output version, which could potentially inform policy decisions, we show that the transfers required by the efficient mechanism create a mutual insurance motive that can serve as an effective rationale for the (gradual) formation of international environmental agreements.     

The ABC mechanism: an incentive compatible payoff mechanism for elicitation of outcome and probability transformations

When it comes to experiments with multiple-round decisions under risk, the current payoff mechanisms are incentive compatible with either outcome weighting theories or probability weighting theories, but not both. In this paper, I introduce a new payoff mechanism, the Accumulative Best Choice (“ABC”) mechanism that is incentive compatible for all rational risk preferences. I also identify three necessary and sufficient conditions for a payoff mechanism to be incentive compatible for all models of decision under risk with complete and transitive preferences. I show that ABC is the unique incentive compatible mechanism for rational risk preferences in a multiple-task setting. In addition, I test empirical validity of the ABC mechanism in the lab. The results from both a choice pattern experiment and a preference (structural) estimation experiment show that individual choices under the ABC mechanism are statistically not different from those observed with the one-round task experimental design. The ABC mechanism supports unbiased elicitation of both outcome and probability transformations as well as testing alternative decision models that do or do not include the independence axiom.

     

Informal insurance in social networks

This paper studies bilateral insurance schemes across networks of individuals. While transfers are based on social norms, individuals must have the incentive to comply. We investigate the structure of self-enforcing insurance networks. Network links play two distinct and possibly conflictual roles. They act as conduits for both transfers and information; affecting the scope for insurance and the severity of punishments upon noncompliance. Their interaction leads to a characterization of stable networks as suitably “sparse” networks. Thickly and thinly connected networks tend to be stable, whereas intermediate degrees of connectedness jeopardize stability. Finally, we discuss the effect of discounting on stability.     

Economies with observable types

We study economies of asymmetric information with observable types. Trade takes place in lotteries. Individuals face a standard budget constraint, while the incentive compatibility constraints are imposed on the production set of the intermediaries. This formalization encompasses moral hazard, as in [Jerez, 2003] and [Jerez, 2005], and private information economies. Equilibrium allocations are constrained efficient, but, contrary to what stated for example in Jerez (2005), the set of equilibrium allocations may be empty and the Second Welfare Theorem may fail. This happens for two reasons. First, constrained efficient allocations may violate the necessary and sufficient conditions of price supportability for the individuals. Second, even when constrained efficient allocation are price supportable, they may fail to be a profit maximizing choice of the firm at the individual supporting prices. To restore existence of an equilibrium the firm has to be restricted to supply allocations with support in the set of incentive compatible contracts.     

The informational effects of competition and collusion in legislative politics

We use a mechanism design approach to study the organization of interest groups in an informational model of lobbying. Interest groups influence the legislature only by communicating private information on their preferences and not by means of monetary transfers. Interest groups have private information on their ideal points in a one-dimensional policy space and may either compete or adopt more collusive behaviors. Optimal policies result from a trade-off between imposing rules which are non-responsive to the groups' preferences and flexibility that pleases groups better. Within a strong coalition, interest groups credibly share information which facilitates communication of their joint interests, helps screening by the legislature and induces flexible policies responsive to the groups' joint interests (an informativeness effect). Competing interest groups better transmit information on their individual preferences (a screening effect). The socially and privately optimal organization of lobbying favors competition between groups only when their preferences are not too congruent with those of the legislature. With more congruence, a strong coalition is preferred. Finally, within a weak coalition, interest groups must design incentive compatible collusive mechanisms to share information. Such weak coalitions are always inefficient.     

Sequential communication with ex post participation constraints

This paper examines an informed principal-agent game with ex post participation constraints for the agent. It shows that the players do not lose by communicating in turn among themselves rather than simultaneously if and only if the principal communicates first. It then considers every Bayesian incentive compatible allocation rules that assign non-negative payoffs for one player in a bilateral asymmetric information framework. It provides necessary and sufficient conditions for sequential communication to be as efficient as simultaneous communication in implementing these allocation rules when the player with unbounded payoffs moves first.     

增强城市群综合承载能力的政府合作机制研究

在明确增强城市群综合承载能力的内涵与标志的基础上,基于机制设计理论,以增强城市群综合承载能力为目标,以城市群内各地方政府为参与主体,按照"资源有效配置、信息有效利用、激励相容"三个机制设计标准进行了增强城市群综合承载能力的政府合作机制设计,并构建了政府合作增强城市群综合承载能力的理论分析模型,为以政府合作的方式增强城市群综合承载能力提供了对策建议和分析框架。     

Ex ante efficiency implies incentive compatibility

We show that when agents become informationally negligible in a large economy with asymmetric information, every ex ante efficient allocation must be incentive compatible. This means that any ex ante core or Walrasian allocation is incentive compatible. The corresponding result is false for fixed finite-agent economies with asymmetric information. An example is also constructed to show that the ex post version of the result does not hold. Furthermore, we show that the result is sharp in the sense that it will fail to hold if one relaxes any of the main assumptions, namely, strong conditional independence on the information structure, strict concavity on the utility functions, type independence on the utility functions and endowments.      

PARETO EFFICIENCY AND WEIGHTED MAJORITY RULES

We consider the design of decision rules in an environment with two alternatives, independent private values and no monetary transfers. The utilitarian rule subject to incentive compatibility constraints is a weighted majority rule, where agents' weights correspond to expected gains given that their favorite alternative is chosen. It is shown that a rule is interim incentive efficient if and only if it is a weighted majority rule, and we characterize those weighted majority rules that are ex ante incentive efficient. We also discuss efficiency in the class of anonymous mechanisms and the stability of weighted majority rules.     

The communication cost of selfishness

We consider how many bits need to be exchanged to implement a given decision rule when the mechanism must be ex post or Bayesian incentive compatible. For ex post incentive compatibility, the communication protocol must reveal enough information to calculate monetary transfers to the agents to motivate them to be truthful (agents' payoffs are assumed to be quasilinear in such transfers). For Bayesian incentive compatibility, the protocol may need to hide some information from the agents to prevent deviations contingent on the information. In both settings with selfish agents, the communication cost can be higher than in the case in which the agents are honest and can be relied upon to report truthfully. The increase is the “communication cost of selfishness.” We provide an exponential upper bound on the increase. We show that the bound is tight in the Bayesian setting, but we do not know this in the ex post setting. We describe some cases where the communication cost of selfishness proves to be very low.     

Optimal voting schemes with costly information acquisition

A group of individuals with identical preferences must make a decision under uncertainty about which decision is best. Before the decision is made, each agent can privately acquire a costly and imperfect signal. We discuss how to design a mechanism for eliciting and aggregating the collected information so as to maximize ex-ante social welfare.We first show that, of all mechanisms, a sequential one is optimal and works as follows. At random, one agent at a time is selected to acquire information and report the resulting signal. Agents are informed of neither their position in the sequence nor of other reports. Acquiring information when called upon and reporting truthfully is an equilibrium.We next characterize the ex-ante optimal scheme among all ex-post efficient mechanisms. In this mechanism, a decision is made when the precision of the posterior exceeds a cut-off that decreases with each additional report. The restriction to ex-post efficiency is shown to be without loss when the available signals are sufficiently imprecise. On the other hand, ex-post efficient mechanisms are shown to be suboptimal when the cost of information acquisition is sufficiently small.     

Optimality versus practicality in market design: A comparison of two double auctions

We consider a market for indivisible items with m buyers and m sellers. Traders privately know their values/costs, which are statistically dependent. Two mechanisms are considered. The buyer's bid double auction collects bids and asks from traders and determines the allocation by selecting a market-clearing price. It fails to achieve all possible gains from trade because of strategic bidding. The designed mechanism is a revelation mechanism in which honest reporting of values/costs is incentive compatible and all gains from trade are achieved. This optimality, however, comes at the expense of plausibility: (i) the monetary transfers among the traders are defined in terms of the traders' beliefs about each other's value/cost; (ii) a trader may suffer a loss ex post; (iii) the mechanism may run a surplus/deficit ex post. We compare the virtues of the simple yet mildly inefficient buyer's bid double auction to the flawed yet perfectly efficient designed mechanism.     

Abstract types and distributions in independent private value auctions

A large body of the mechanism design literature relies on convexity assumptions on the set of types (that is, on the domain of the mechanism). In this note I show that, at least for auction mechanisms with independent signals, it is always possible to extend incentive compatible mechanisms to incentive compatible mechanisms defined on any larger set of types. I acknowledge the comments of Luis Braido, Sérgio Orioli, Humberto Moreira, Frank Page and an anonymous referee. The financial support of Edital Universal 02/06, CNPq is gratefully acknowledged.     

INCENTIVE COMPATIBLE MECHANISM DESIGN AND FIRM GROWTH: EXPERIENCES FROM TELECOMMUNICATIONS SECTOR REGULATION

ABSTRACT**: This article evaluates the impact of the introduction of incentive regulation on firm growth among the population of local exchange carriers in the US telecommunications industry between 1988 and 2001. The results show that the rate of return method and other intermediate incentive schemes have had a negative impact on firm growth. Conversely, the introduction of pure price caps schemes had a positive and significant impact on firms’ growth. These results highlight the importance of proper and appropriate incentive compatible mechanism design in motivating firms to strive for superior performance.     

PRICING REGULATIONS AND NETWORK TECHNOLOGY INVESTMENTS: A RETROSPECTIVE EVALUATION

This article evaluates the impact of the introduction of incentive regulation on technology deployment, as evaluated using two technology deployment metrics, among the population of local exchange carriers in the USA between 1988 and 2001. The regulatory schemes are disaggregated into five categories, permitting examination of heterogeneity among regulatory schemes. The results show that the rate of return method and the other intermediate incentive schemes implemented have had a negative impact on technology deployment. Conversely, the introduction of pure price caps schemes had a positive and significant impact on firms’ technology deployment. These results highlight the importance of appropriate incentive compatible mechanism design in motivating firms to adopt the new and important technologies that have been developed.     

Announcement or Contribution? The Relative Efficiency of Manipulated Lindahl Mechanisms

The private provision mechanism is individually incentive compatible but inefficient. The Lindahl mechanism is efficient but not incentive compatible. We analyze the outcome of the manipulated Lindahl mechanism. When the demand announcements of participants are unrestricted the Lindahl mechanism suffers from multiple equilibria. If the government removes the multiplicity by restricting the functional form of announcements the resulting Lindahl equilibrium can be made approximately efficient. Approximate efficiency is achieved by announcements that are one-dimensional regardless of the number of participants in the mechanism. This is in contrast to mechanisms that achieve exact efficiency but require announcements whose dimensionality increases at the same rate as the number of participants. The mechanism we describe benefits from simplicity at the cost of approximate efficiency. We demonstrate that mechanisms in which a linear demand function is announced are supermodular so play will converge to the Nash equilibrium for a range of learning dynamics.     

REGULATIONS AND STRATEGY: EVIDENCE ON ADVERTISING

This article evaluates the impact of the introduction of incentive regulation on firms’ advertising spending among the population of local exchange carriers in the United States telecommunications industry between 1988 and 2001. The results show that the hybrid rate of return method and other intermediate incentive schemes have a negative relationship with advertising spending. Conversely, the introduction of pure price caps schemes has had a positive and significant impact on firms’ advertising spending. These results highlight the importance of incentive compatible mechanism design in motivating firms to be market oriented and strive for superior performance.     

Mechanisms for a spatially distributed market

We consider the problem of a spatially distributed market with strategic agents. A single good is traded in a set of independent markets, where shipment between markets is possible but costly. The problem has previously been studied in the non-strategic case, in which it can be analyzed and solved as a min-cost-flow problem. We consider the case where buyers and sellers are strategic. Our first result gives a double characterization of the VCG prices, first as distances in a certain residue graph and second as the minimal (for buyers) and maximal (for sellers) equilibrium prices. This provides a computationally efficient, individually rational and incentive compatible welfare maximizing mechanism. This mechanism is, necessarily, not budget balanced and we also provide a budget-balanced mechanism (which is also computationally efficient, incentive compatible and individually rational) that achieves high welfare. Finally, we present results for some extensions of the model.