How are preferences revealed?

Revealed preferences are tastes that rationalize an economic agent's observed actions. Normative preferences represent the agent's actual interests. It sometimes makes sense to assume that revealed preferences are identical to normative preferences. But there are many cases where this assumption is violated. We identify five factors that increase the likelihood of a disparity between revealed preferences and normative preferences: passive choice, complexity, limited personal experience, third-party marketing, and intertemporal choice. We then discuss six approaches that jointly contribute to the identification of normative preferences: structural estimation, active decisions, asymptotic choice, aggregated revealed preferences, reported preferences, and informed preferences. Each of these approaches uses consumer behavior to infer some property of normative preferences without equating revealed and normative preferences. We illustrate these issues with evidence from savings and investment outcomes.     

The structure of the Nash equilibrium sets of standard 2-player games

Summary. In this paper I study a class of two-player games, in which both players action sets are [0,1] and their payoff functions are continuous in joint actions and quasi-concave in own actions. I show that a no-improper-crossing condition is both necessary and sufficient for a finite subset A of to be the set of Nash equilibria of such a game.Received: 21 November 2002, Revised: 9 September 2004, JEL Classification Numbers: C65, C72.I am grateful to an editor of the journal and an anonymous referee for their very helpful comments. I also would like to thank the seminar participants at City University of Hong Kong, Georgia State University, Northwestern University, and Rice University.     

Candidate stability and probabilistic voting procedures

Summary. We extend the analysis of Dutta, Jackson and Le Breton (Econometrica, 2001) on strategic candidacy to probabilistic environments. For each agenda and each profile of voters preferences over running candidates, a probabilistic voting procedure selects a lottery on the set of running candidates. Assuming that candidates cannot vote, we show that random dictatorships are the only unanimous probabilistic voting procedures that never provide unilateral incentives for the candidates to withdraw their candidacy at any set of potential candidates. More flexible probabilistic voting procedures can be devised if we restrict our attention to the stability of specific sets of potential candidates.Received: 4 February 2003, Revised: 14 September 2004, JEL Classification Numbers: D71, D72.This is a revised version of a chapter of my Ph.D. Dissertation submitted to the Universitat Autónoma de Barcelona. I am indebted to my supervisor Salvador Barberá for his advice and constant support. I am grateful to Dolors Berga and an anonymous referee for their detailed comments and suggestions. I thank José Alcalde, Walter Bossert, Bhaskar Dutta, Lars Ehlers, Jordi Massó, Diego Moreno, Clara Ponsatí, Yves Sprumont, and William Thomson for many helpful comments and discussions. I thank the hospitality of the C.R.D.E. at the Université de Montréal and the Department of Economics of the University of Warwick where parts of this research were conducted. Financial support through Research Grant 1998FI00022 from Comissionat per Universitats i Recerca, Generalitat de Catalunya, Research Project PB98-870 from the Ministerio de Ciencia y Tecnología, and Fundación Barrié de la Maza is gratefully acknowledged.     

A general revealed preference theorem for stochastic demand behavior

Summary. We present a general revealed preference theorem concerning stochastic choice behavior by consumers. We show that, when the consumer spends her entire wealth, the Weak Axiom of Stochastic Revealed Preference due to Bandyopadhyay, Dasgupta, and Pattanaik (1999) is equivalent to a restriction on stochastic demand behavior that we call stochastic substitutability. We also show that the relationship between the Weak Axiom of Revealed Preference and Samuelson's inequality in the deterministic theory, and the main result of Bandyopadhyay, Dasgupta, and Pattanaik (1999) are both special cases of our result.Received: 10 September 2001, Revised: 4 April 2003, JEL Classification Numbers: D11. Correspondence to: Prasanta K. PattanaikOur greatest debt is to the referee of this paper, who made numerous helpful suggestions. We thank Robin Cubitt, Kunal Sengupta and seminar audiences at Jawaharlal Nehru University, Indian Statistical Institute, University of East Anglia, Universidad Carlos III, University of Essex and University of Montreal for their helpful comments. Prasanta K. Pattanaik acknowledges his intellectual debt to Salvador Barbera, Tapas Majumdar and Amartya Sen.     

Market and underground activities in a two-sector dynamic equilibrium model

Summary. In this paper a two sector dynamic general equilibrium model is developed in order to evaluate the implications of the underground economy from a business cycle perspective. There are three main results. First, introducing an underground sector improves the fit of the model to the data, especially along several important labor market dimensions. Second, the model produces substantial internal propagation of temporary shocks. Third, it is shown that underground activities offer risk sharing opportunities by allowing households to smooth income through a proper labor allocation between the two sectors.Received: 17 June 2002, Revised: 25 April 2003, JEL Classification Numbers: E320, E260, J22, H200.We have benefited from the comments and suggestions of John Donaldson. We would also like to thank Paolo Siconolfi, Jean Pierre Danthine, Fausto Gozzi, Edmund Phelps, Gustavo Piga, Domenico Tosato, and the participants in the seminars at various universities, David Giles and Stefano Pisani for providing useful information on the underground data, Francesca Caponi for the comments and the information concerning the legal and fiscal aspects involved in the calibration, and Glenn Williams for the research assistance. Finally, we thank two anonymous referees for helpful comments on this and on earlier versions of the paper. Chiarini acknowledges financial support from the Ateneo Research fund of the University of Rome, La Sapienza, Dinamiche dell'integrazione europea e scelta di politica economica. All errors are ours. Correspondence to: F. Busato     

Existence,uniqueness, and stability of equilibrium in an OLG economy

Summary. This paper presents sufficient conditions for the existence of a unique and globally stable steady state equilibrium for OLG economies with production. The conditions impose separate requirements on the utility and production functions. Moreover, the conditions do not require assumptions concerning the third order derivatives of the production and utility functions.Received: 12 August 2002, Revised: 7 January 2003, JEL Classification Numbers: D50, D91, E13, O41.I would like to thank Nick Baigent, Laurie Conway, Karl Farmer, Christian Gehrke, and Hideo Konishi for helpful comments. I am grateful to an anonymous referee for his or her comments.     

A characterization of social choice correspondences that implement the core of simple games

In a coalitional voting game, an alternative is said to be in the core when no majority is willing to replace it with another alternative. A social choice correspondence is a mapping which associates any profile of voters’ preferences with a non-empty subset of the set of alternatives, which is understood as the set of selected outcomes. We characterize the social choice correspondences which always select the core of a simple game for any profile of preferences. This work was completed when B. Tchantcho was Visiting assistant Professor at UTA (University of Texas at Arlington). We acknowledge the support of the Department of Mathematics of UTA. We are most grateful to R. Pongou of Brown University, USA for his help and advice. We sincerely thank N.G Andjiga for his helpful comments and we are indebted to two anonymous referees for their helpful comments.     

An empirical note about additive outliers and nonstationarity in Latin-American inflation series

This note shows the empirical dangers of the presence of large additive outliers when testing for unit roots using standard unit root statistics. Using recent proposed procedures applied to four Latin-American inflation series, I show that the unit root hypothesis cannot be rejected.Jel classification: C2, C3, C5I want to thank Pierre Perron for useful comments on a preliminary version of this paper. Helpful comments from an anonymous referee, and Yiagadeesen Samy are appreciated. I thank the Editor Baldev Raj for useful comments about the final structure of this paper. Finally, I also thank André Lucas for helpful suggestions concerning the use of his nice computer program Robust Inference Plus Estimation (RIPE).First revision received: August 2001/Final revision received: December 2002     

Binary games with many players

Summary. We examine a problem with n players each facing the same binary choice. One choice is superior to the other. The simple assumption of competition - that an individual’s payoff falls with a rise in the number of players making the same choice, guarantees the existence of a unique symmetric equilibrium (involving mixed strategies). As n increases, there are two opposing effects. First, events in the middle of the distribution - where a player finds itself having made the same choice as many others - become more likely, but the payoffs in these events fall. In opposition, events in the tails of the distribution - where a player finds itself having made the same choice as few others - become less likely, but the payoffs in these events remain high. We provide a sufficient condition (strong competition) under which an increase in the number of players leads to a reduction in the equilibrium probability that the superior choice is made.Received: 24 July 2003, Revised: 24 January 2005, JEL Classification Numbers: C72, D02, D49, L19.Flavio M. Menezes: Correspondence toThis paper has benefitted from comments by an anonymous referee and seminar participants at the ANU, Boston University, Harvard University Law, Economics and Organization Seminar, University of Wisconsin and at the Econometrics Society Australasian Meetings, Auckland New Zealand. We also thank Lucian Bebchuk, Eddie Dekel, Oliver Hart, Luis Kaplov, Paulo Monteiro and John Quiggin for very useful comments. All errors are our own. Menezes acknowledges the financial support from ARC (grant no. 00000055) and the hospitality of EPGE/FGV and RSPAS/ANU.     

Second price auctions on general preference domains: two characterizations

Auction theory usually assumes the quasi-linearity of individual preferences. We drop this assumption and define an extension of second price mechanisms that applies to general preferences. It turns out that the extended second price mechanisms are the only rules satisfying efficiency, strategy-proofness, and a mild non-imposition property. Their definition is simple just as much as the definition of usual second price mechanisms: everyone reports his maximum willingness to pay and the bidder whose reported value is highest buys the auctioned object for the price equal to the second highest reported value. The characterization is valid if efficiency is replaced by envy-freeness. I gratefully acknowledge an associate editor and two anonymous referees for their very helpful comments. Hiroki Saitoh and Shigehiro Serizawa independently obtain a result that is closely related to my main result (see, Remark in Sect. 1). I thank them for sending me the paper and communication, and Yuji Fujinaka for informing me about their work. I also thank the financial support by KAKENHI (19310031).     

Existence and specific characters of rentiers: a savers-spenders theory approach

Summary. Using the savers-spenders theory developed by Mankiw (2000, AER), we propose microfoundations to the existence of rentiers in macroeconomic growth models. From an OLG model which acknowledges the great heterogeneity of consumer behavior apparent in the data, we capture the dynamic considerations of potential rentiers as a natural consequence of intertemporal utility maximization and we analyze realistic characteristics (proportion, wealth, propensity to save) of rentiers.JEL Classification Numbers: E13, D64, J22.This paper is adapted from the fourth chapter of my Ph.D Thesis. Then, I thank Alain VENDITTI, my Ph.D Supervisor and Antoine dAUTUME and Pierre PESTIEAU my Ph.D Referees. Earlier version of this paper were presented at the International conference: New perspectives on (un)stability: the role of heterogeneity at Marseille, June 7-9, 2001 and at the X-th Spring School of the Associated European Laboratory (CNRS-FNRS/CORE-GREC-GREQAM) at Aix, 2001. I thank conference participants, in particular Olivier CHARLOT, Christian GHIGLINO, Kiminori MATSUYAMA and Philippe MICHEL for suggestions, helpful comments and discussions. I also thank a referee of this journal for his constructive comments.     

Ranking investment projects

Summary. This paper describes conditions under which one investment project dominates a second project in terms of net present value, irrespective of the choice of the discount rate. The resulting partial ordering of projects has certain similarities to stochastic dominance. However, the structure of the net present value function leads to characterizations that are quite specific to this context. Our theorems use Bernstein's (1915) innovative results on the representation and approximation of polynomials, as well as other general results from the theory of equations, to characterize the partial ordering. We also show how the ranking is altered when the range of discount rates is limited or the rate varies period by period. Received: January 5, 2002; revised version: October 29, 2002 RID="*" ID="*" We thank Robert Driskill, Andrea Maneschi, Roy Radner, and participants of seminars at NYU, Notre Dame, Purdue, and Washington University for helpful comments. The present version of the paper has benefited from comments by a referee and the editor. Foster is grateful for support from the John D. and Catherine T. MacArthur Foundation through its network on Inequality and Poverty in Broader Perspective. Correspondence to: T. Mitra     

Resolving distributional conflicts between generations

Summary. We describe a new approach to the problem of resolving distributional conflicts between an infinite and countable number of generations. We impose conditions on the social preferences that capture the following idea: If preference (or indifference) holds between truncated paths for infinitely many truncating times, then preference (or indifference) holds also between the untruncated infinite paths. In this framework we use such conditions to (1) characterize different versions of leximin and utilitarianism by means of equity conditions well-known from the finite setting, and (2) illustrate the problem of combining Strong Pareto and impartiality in an intergenerational setting.Received: 8 May 2002, Revised: 12 June 2003, JEL Classification Numbers: D63, Q01.Correspondence to: Geir B. AsheimWe thank Kaushik Basu, Marc Fleurbaey, David Miller, Tapan Mitra, Lars-Gunnar Svensson, and an anonymous referee for helpful comments. Asheim gratefully acknowledges the hospitality of the Stanford University research initiative on the Environment, the Economy and Sustainable Welfare, and financial support from the Hewlett Foundation through this research initiative.     

Nash equilibrium in games with incomplete preferences

Summary. This paper investigates Nash equilibrium under the possibility that preferences may be incomplete. I characterize the Nash-equilibrium-set of such a game as the union of the Nash-equilibrium-sets of certain derived games with complete preferences. These games with complete preferences can be derived from the original game by a simple linear procedure, provided that preferences admit a concave vector-representation. These theorems extend some results on finite games by Shapley and Aumann. The applicability of the theoretical results is illustrated with examples from oligopolistic theory, where firms are modelled to aim at maximizing both profits and sales (and thus have multiple objectives). Mixed strategy and trembling hand perfect equilibria are also discussed.Received: 22 September 2003, Revised: 24 June 2004, JEL Classification Numbers: D11, C72, D43.I would like to thank Jean-Pierre Benôit, Juan Dubra, Alejandrio Jofre, Debraj Ray, Kim-Sau Chung and the seminar participants at NYU and at the Universidad de Chile for their comments. I am most grateful to Efe Ok, for his comments, criticism, suggestions and questions.     

Random Price Discrimination

When a monopolist randomly sorts customers, price discrimination “concavifies” the revenue function of the firm, so that it may be optimal for a monopolist to divide customers into groups that have the same demand function and charge them different prices. It is impossible to rule out this type of result whenever the revenue function is somewhere convex in the “economically relevant” set of quantities, because there always exists a non-decreasing cost function that leads to that conclusion. It is also impossible to rule out the case where, with respect to monopoly, the firm raises or lowers price to all classes and, accordingly, the case where the social welfare decreases or increases. Received December 13, 2001; revised version received June 3, 2002 Published online: February 17, 2003 I am indebted to Carlo Beretta, Giuseppe Colangelo, Umberto Galmarini, Guido Merzoni, Gerd Weinrich and especially to Carla Peri for helpful discussions and comments. I have also benefited from insightful suggestions of three anonymous referees. Finally, I wish to thank participants to seminars at the Catholic University of Milan and University of Bologna. The usual disclaimer applies. Funds from MIUR are gratefully acknowledged.     

Procedural choice

Summary. In this paper, we attempt to combine the concept of a choice function with a procedural aspect. We examine an individuals choices over alternatives when the available options are linked either to the procedure by which these alternatives came into existence or to the degree of availability of other options. The procedural aspect behind availability may prompt an individual to refuse to choose so that the choice set becomes empty. This particular aspect is used to study different cases that are characterized axiomatically. We relate our conditions to well-known consistency conditions from standard choice theory.Received: 2 December 2002, Revised: 18 August 2003JEL Classification Numbers: D62, D63, D71.Correspondence to: Wulf GaertnerThe first author would like to thank Volkswagen-Stiftung for generous financial support. For helpful comments and suggestions we are grateful to Fuad Aleskerov, Nick Baigent, Nancy Cartwright, Kotaro Suzumura as well as to seminar participants at various universities and audiences at several conferences.     

Stable partitions in a model with group-dependent feasible sets

Summary. In this paper we consider a model of group formation where group of individuals may have different feasible sets. We focus on two polar cases, increasing returns, when the set of feasible alternatives increases if a new member joins the group, and decreasing returns, when a new member has an opposite effect and reduces the number of alternatives available for the enlarged group. We examine two notions, stability and strong stability of group structures, that correspond to Nash and Strong Nash equilibrium of the associated non-cooperative game, and identify the classes of stable and strongly stable environments.Received: 29 June 2003, Revised: 17 February 2004, JEL Classification Numbers: C71, C72, D62, D71.The previos version of this paper has been written while the second author was visiting the Technical University of Dresden. He wishes to thank the Alexander von Humboldt Foundation for its generous support and the Technical University of Dresden for its hospitality. The authors are grateful to an anonymous referee for useful comments.     

Nash implementing non-monotonic social choice rules by awards

Summary. By a slight generalization of the definition of implementation (called implementation by awards), Maskin monotonicity is no more needed for Nash implementation. In fact, a weaker condition, to which we refer as almost monotonicity is both necessary and sufficient for social choice correspondences to be Nash implementable by awards. Hence our framework paves the way to the Nash implementation of social choice rules which otherwise fail to be Nash implementable. In particular, the Pareto social choice rule, the majority rule and the strong core are almost monotonic (hence Nash implementable by awards) while they are not Maskin monotonic (hence fail to be Nash implementable in the standard framework).Received: 12 April 2004, Revised: 18 March 2005, JEL Classification Numbers: D 79.I thank François Maniquet, Efe Ok and Ipek Ozkal-Sanver for their valuable contributions. The paper is part of a project on Electoral System Design supported by Bilgi University Research Fund.     

Finding a Nash equilibrium in spatial games is an NP-complete problem

Summary. We consider the class of (finite) spatial games. We show that the problem of determining whether there exists a Nash equilibrium in which each player has a payoff of at least k is NP-complete as a function of the number of players.Received: 15 September 2002, Revised: 9 March 2003, JEL Classification Numbers: C72.Correspondence to: H. HallerWe thank a referee for helpful comments. The hospitality of the Institute of Economics, University of Copenhagen, and the Institute for Advanced Studies, Vienna, is gratefully acknowledged by the third author.