Private information revelation in common-value auctions

When a seller has information that could help bidders to estimate asset value, a dictum of auction theory has been that all such information should be publicly announced to bidders. The possibility of privately revealing this information to one or more bidders is introduced. Seller in some circumstances may attain higher expected revenue through revealing his information privately. Examples show that the role of private revelation is more complex than simply generating bidder asymmetry.     

Full revelation of information in Sender-Receiver games of persuasion

We provide necessary and sufficient conditions on both players' preferences and information that can be certified for a Sender-Receiver game to possess a separating equilibrium, as well as sufficient conditions for every equilibrium of such a game to be separating. Accordingly, we generalize Seidmann and Winter's [D.J. Seidmann, E. Winter, Strategic information transmission with verifiable messages, Econometrica 65 (1997) 163-170] results to games with partial provability.     

Menu-dependent preferences and revelation principle

We extend the set of preferences to include menu-dependent preferences and characterize the domain in which the revelation principle holds. A weakening of the well-known contraction consistency is shown to define a subset of this domain. However, we show that minimax-regret preference can be outside the domain.     

Size and information revelation in securities trading

We examine differences in information content between order submission sizes and trade sizes by U.S. equity traders. Increasing (decreasing) order submission (trade) size is reflective of information. The result suggests that better-informed traders want to trade in a large size, but that they engage in stealth trading practices or break larger orders into smaller sizes in order to conceal information. While prior studies tend to narrowly focus on trade executions at the market-centre level, our findings indicate that order submission size varies significantly from trade size and that both sizes are informative about future prices, albeit in an inverse manner.     

Polling games and information revelation in the Downsian framework

We investigate the incentives faced by poll respondents when candidates use polling data to inform their selection of policy platforms. Focusing on models with a unidimensional policy space, single peaked preferences and two office-seeking candidates observing a summary statistic from polls that ask respondents their preferences, we find that for most environments honest poll response cannot occur in a perfect Bayesian equilibrium. However, simple partially-revealing equilibria exist when the poll only asks respondents which party or candidate they prefer. When the candidates learn the sample average or see all the data, there are partially revealing equilibria that mimic those of the binary message game. Interpretation of polling data requires knowledge of the equilibrium played as the meanings of poll responses are endogenously determined. The analysis suggests that naive use of polling data may be misleading.     

A two-stage core with applications to asset market and differential information economies

Summary. We introduce a new core concept, called the two-stage core, which is appropriate for economies with sequential trade. We prove a general existence theorem and present two applications of the two-stage core: (i) In asset markets economies where we extend our existence proof to the case of consumption sets with no lower bound, in order to capture the case of arbitrary short sales of assets. Further, we show that the two-stage core is non empty in the Hart (1975) example where a rational expectations equilibrium fails to exist. (ii) In differential information economies where we provide sufficient conditions for the incentive compatibility of trades. Namely, that no coalition of agents can misreport the true state and provide improvements to all its members, even by redistributing the benefits from misreporting. Received: December 20, 1995; revised version: December 6, 1996     

Economic Development, Trade and Wages

We present models that allow the use of unskilled and skilled labor as well as capital and land. Thus agriculture, important in developing countries, can be included as well as two types of labor and a single (or two) type(s) of physical capital. The models are related to the simple 3×2 specific factors structure by means of what is called the linear neighborhood structure, wherein no activity uses more than two factors, and the two types of labor work in separated sectors, using in common a type of physical capital. We discuss how wage rate changes are related when endowments change, when agriculture becomes traded and prices rise, and when unskilled labor becomes educated and joins the ranks of skilled workers.     

Preference revelation with a limited number of indifference classes

Suppose that g is a strategy-proof social choice rule on the domain of all profiles of complete and transitive binary relations that have exactly m indifference classes. If and the range of g has three or more members, then g is dictatorial. If m = 2, then for any set X of feasible alternatives, there exist non-dictatorial and strategy-proof rules that are sensitive to the preferences of every individual and which have X as range.     

Insider trading and information revelation with the introduction of futures markets

We establish a theoretical model with informed trading in which both of individual stock futures and its underlying stock are traded in the market. With the introduction of the futures, the paper shows that an informed trader's position of futures usually motivates him or her to trade more aggressively in the stock market at the expiration day. This also worsens the adverse selection problem and makes the stock market become less liquid. Moreover, the increase of the informed trading accelerates the information revelation and improves market efficiency on the expiration date. Finally, our results suggest that price manipulation could be one factor that affects the market liquidity and market efficiency when the futures are introduced into the market.     

The relative contributions of private information sharing and public information releases to information aggregation

We calculate learning rates when agents are informed through public and private observation of other agents' actions. We characterize the evolution of the distribution of posterior beliefs. If the private learning channel is present, convergence of the distribution of beliefs to the perfect-information limit is exponential at a rate equal to the sum of the mean arrival rate of public information and the mean rate at which individual agents are randomly matched with other agents. If, however, there is no private information sharing, then convergence is exponential at a rate strictly lower than the mean arrival rate of public information.     

Asymmetric information may protect the commons: The welfare benefits of uninformed regulators

We examine an entry-deterrence model in the commons. We investigate in which contexts asymmetric information among firms becomes welfare improving, and in which settings an uninformed regulator may prefer to assess and disseminate information about the available stock among firms.     

Delay and information aggregation in stopping games with private information

We consider equilibrium timing decisions in a model with a large number of players and informational externalities. The players have private information about a common payoff parameter that determines the optimal time to invest. They learn from each other in real time by observing past investment decisions. We develop new methods of analysis for such large games, and we give a full characterization of symmetric equilibria. We show that the equilibrium statistical inferences are based on an exponential learning model. Although the beliefs converge to truth, learning takes place too late. Ex-ante welfare is strictly between that without observational learning and that with full information.     

Trade and product market policies in upstream sectors and productivity in downstream sectors: Firm-level evidence from China

This paper explores the heterogeneous productivity impact of trade, product market and financial market policies over the last decade in China. The paper makes a critical distinction between downstream and upstream industries, focusing on the indirect effects of regulation in upstream industries on firm performance in downstream manufacturing industries. We identify the differential effect of these policies on firm productivity growth depending on how far incumbents are relative to the technological frontier. Trade and product market reforms are found to deliver stronger gains for firms that are closer to the industry-level technological frontier, while the reverse holds for financial market reforms. The key conclusion that can be derived from the empirical analysis is that further product, trade and financial market reforms would bring substantial gains in China and could therefore speed up the convergence process. Taken at face value, the empirical estimates would imply that aligning product, trade and financial market regulation to the average level observed in OECD countries would bring aggregate manufacturing productivity gains of respectively 9%, 3% and 6.5% after 5 years.     

The law of supply in games, markets and matching models

Summary In large games with transferable utility, core payoffs satisfy a comparative statics property: If the proportion of one type of player increases, then the core payoff to that type of player decreases (does not increase). Markets with transferable utility satisfy a similar property: if the aggregate supply of a commodity increases, its value relative to the value of all commodities decreases. In market games, if one type of agent becomes more plentiful, his competitive payoff falls, and its decrease is engineered by a decrease in the relative value of his endowment.We thank Bob Anderson, Joe Farrell, Steve Goldman, Chris Shannon, seminar participants of the Mathematical Economics Seminar at Berkeley (August 1994), the University of Pittsburg (November 1994), Tel Aviv University and the Institute on Rationality at the Hebrew University (January 1995), and especially Vince Crawford for useful discussion.     

Blackwell's ordering and public information

We characterize a precise comparative static on welfare and the amount of public information in an economy under uncertainty. Results dating to Hirshleifer (Amer. Econom. Rev. 61 (1971) 561) have suggested that information can have negative value in such a setting, but counterexamples using competitive equilibrium outcomes have suppressed general results to this effect. We show that under the solution concept of implementable allocations, the negative relationship between more public information in the sense of Blackwell and welfare is fully general. Furthermore, Blackwell's ranking is necessary as well as sufficient to obtain our ranking, and hence ours provides an equivalent characterization of his ordering.     

Efficiency and information aggregation in large uniform-price auctions

We prove that the equilibria of a large interdependent-value, uniform-price auction model where bidders have arbitrary preferences for multiple units can be approximated by a nonatomic exchange economy. We show that the uniform-price auction is approximately efficient with a large number of participants and asymptotically aggregates idiosyncratic bidder information into the market price. More generally our analysis framework provides conditions justifying the use of nonatomic limit model approximations to analyze the large-market behavior of game-theoretic models. We demonstrate continuity requirements on the economic primitives sufficient for the equilibrium strategies of the two models to converge as the number of participants in the finite game approaches infinity.     

Strategic information transmission networks

We study a model of multi-player communication. Privately informed decision makers have different preferences about the actions they take, and communicate to influence each others? actions in their favor. We prove that the equilibrium capability of any player to send a truthful message to a set of players depends not only on the preference composition of those players, but also on the number of players truthfully communicating with each one of them. We establish that the equilibrium welfare depends not only on the number of truthful messages sent in equilibrium, but also on how evenly truthful messages are distributed across decision makers.     

Equilibrium theory with asymmetric information and with infinitely many commodities

The traditional deterministic general equilibrium theory with infinitely many commodities cannot cover economies with private information constraints on the consumption sets. We bring the level of asymmetric information equilibrium theory at par with that of the deterministic one. In particular, we establish results on equilibrium existence for exchange economies with asymmetric (differential) information and with an infinite dimensional commodity space. Our new equilibrium existence theorems include, as a special case, classical results, e.g. Bewley [Existence of equilibria in economies with infinitely many commodities, J. Econ. Theory 4 (1972) 514-540] or Mas-Colell [The price equilibrium existence problem in topological vector lattices, Econometrica 54 (1986) 1039-1053].     

Recursive utility and preferences for information

Summary. This paper presents an axiomatic foundation for recursive utility that captures the role of the timing of resolution of uncertainty without relying on exogenously specified objective beliefs. Two main representation results are proved. In the first one, future utility enters the recursion through the type of general aggregators considered in Skiadas (1997a), and as a result the formulation is purely ordinal and free of any probabilities. In the second representation these aggregators are conditional expectations relative to subjective beliefs. A new recursive representation incorporating disappointment aversion is also suggested. The main methodological innovation of the paper derives from the fact that the basic objects of choice are taken to be pairs of state-contingent consumption plans and information filtrations, rather than the temporal (objective) lotteries of the existing literature. It is shown that this approach has the additional benefit of being directly applicable to the continuous-time version of recursive utility developed by Duffie and Epstein (1992). Received: February 18, 1997; revised version: July 18, 1997     

采用EQ-5D评估2型糖尿病患者的生活质量及影响因素研究

目的：采用EuroQol五维调查问卷表（EQ-5D）对2型糖尿病患者健康相关的生活质量进行评价,并分析其主要影响因素,探讨健康状况发展与生活质量下降的关系。方法：采用EQ-5D问卷及访问,对南京大学附属南京鼓楼医院内分泌门诊256例2型糖尿病患者生活质量和健康状况进行研究。结果全体患者EQ-5D分值平均0．790±0．158。理想控制的患者组平均值0．836（0．810～0．861;95％CI）,良好控制和控制差的组的分值分别相当于理想患者的92．2％、84．8％。出现一种或多种并发症的患者分值0．692（0．667～0．717．95％CI）,未出现并发症的患者提高到0．863（0．842～0．883,95％CI）。各种并发症的发生发展与血糖控制情况对生活质量影响程度最强。结论：EQ-5D量表适用于中国2型糖尿病患者健康状况测量,适宜成本-效果分析研究。血糖控制不理想和各并发症的发生发展是患者生活质量下降的主要影响因素。