Competition between asymmetrically informed principals

Summary. This paper derives the set of equilibria for common agency games in which the principals compete in piece rates and lump sum payments and one principal has incomplete information about the agent's preferences. We show that the uninformed principal's expected payoff function is discontinuous with respect to the identity of the marginal agent type. This discontinuity is shown to support an open set of equilibria. For games in which the first-best equilibrium strategies are measurable with respect to the uninformed principal's information partition, this result implies the existence of an open set of Pareto inefficient equilibria. Received: December 5, 1995; revised version August 18, 1996     

Stability and Segregation in Group Formation

This paper presents a model of group formation based on the assumption that individuals prefer to associate with people similar to them. It is shown that, in general, if the number of groups that can be formed is bounded, then a stable partition of the society into groups may not exist. (A partition is defined as stable if none of the individuals would prefer be in a different group than the one he is in.) However, if individuals' characteristics are one-dimensional, then a stable partition always exists. We give sufficient conditions for stable partitions to be segregating (in the sense that, for example, low-characteristic individuals are in one group and high-characteristic ones are in another) and Pareto efficient. In addition, we propose a dynamic model of individual myopic behavior describing the evolution of group formation to an eventual stable, segregating, and Pareto efficient partition. Journal of Economic Literature Classification Numbers: C72, H41.     

Rivalry, Exclusion, and Coalitions

This paper analyzes a model where groups can attain exclusive ownership of a resource by means of a contest. We show that more concave production technologies and more egalitarianism within groups induce higher levels of social conflict. We then study endogenous coalition formation. Under cooperative exploitation of the resource, the grand coalition is the efficient partition but there exists a strong tendency toward bipartisan conflicts. Under noncooperative exploitation, conflict can ex ante Pareto dominate peaceful access and it becomes more difficult to support the grand coalition as a stable structure.     

Information, trade and incomplete markets

The no-trade result of Milgrom and Stokey, J Econ Theory 26:17–27 (1982), states that if rational traders begin with an ex-ante Pareto optimal allocation then the arrival of information cannot generate trade. This paper allows traders to trade before and after the arrival of information. If there are enough securities to hedge against all payoff relevant risk, then the preinformation-arrival allocation is Pareto optimal and information arrival has no effect. This no-retrade result is the competitive analog of the no-trade result of (1982). However, information generically generates trade when markets are state-contingent incomplete.We thank seminar participants at Cambridge, Carnegie Mellon,Cornell, Essex, London, Maastricht, USC, and York and participants at the 2003 SITE, the 2003 SAET and the Fall 2002 Cornell–Penn State Macro Conference. We also thank Karl Shell and a referee for this journal for useful comments     

Market Entry Regulation and International Competition*

We analyze a non‐cooperative two‐country game where each government decides whether to allow free market entry of firms or to regulate market access. We show that a Pareto‐efficient allocation may result in equilibrium. In particular, if the cost difference between home and foreign production is “significant,” production will be located in the cost‐efficient country exclusively; and if this cost difference is even “substantial,” the induced allocation is also Pareto efficient. Only if the cost difference is “insignificant,” production may take place in both countries and the allocation is inefficient.     

Exchange and optimality

Summary. A feasible social state is irreducible if and only if, for any non-trivial partition of individuals into two groups, there exists another feasible social state at which every individual in the first group is equally well-off and someone strictly better-off. Competitive equilibria decentralize irreducible Pareto optimal social states. Received: September 9, 1996; revised version: February 11, 1998     

On the difficulty of combining actual and potential criteria for an increase in social welfare

Summary. This paper examines two problems associated with the use of potential Pareto criteria in welfare economics. The first problem is the well-known intransitivity of the compensation criteria à la Kaldor-Hicks-Scitovsky. The second problem is the possible incompatibility between the Chipman-Moore-Samuelson criterion and the Pareto principle. The main result of this paper is that, in order to avoid either of these problems, it is necessary and sufficient that the domain to which these criteria are used is such that the Chipman-Moore-Samuelson criterion encompasses completely the Pareto criterion. When interpreted in a standard economic environment, this result is shown to be equivalent to Gorman's requirement of non-crossing between utility possibility frontiers. Received: June 18, 1998; revised version: March 2, 2000     

Social conflict and growth

Despite the predictions of the neoclassical theory of economic growth, we observe that poor countries have invested at lower rates and have not grown faster than rich countries. To explain these empirical regularities we provide a game-theoretic model of conflict between social groups over the distribution of income. Among all possible equilibria, we concentrate on those that are on the constrained Pareto frontier. We study how the level of wealth and the degree of inequality affects growth. We show how lower wealth can lead to lower growth and even to stagnation when the incentives to domestic accumulation are weakened by redistributive considerations.     

Is the Pareto–Lévy law a good representation of income distributions?

Mandelbrot (Int Econ Rev 1:79–106, 1960) proposed using the so-called Pareto–Lévy class of distributions as a framework for representing income distributions. We argue in this article that the Pareto–Lévy distribution is an interesting candidate for representing income distributions because its parameters are easy to interpret and it satisfies a specific invariance-under-aggregation property. We also demonstrate that the Gini coefficient can be expressed as a simple formula of the parameters of the Pareto–Lévy distribution. We subsequently use income data for Norway and seven other OECD countries to fit the Pareto–Lévy distribution as well as the Generalized Beta type II (GB2) distribution. The results show that the Pareto–Lévy distribution fits the data better than the GB2 distribution for most countries, despite the fact that GB2 distribution has four parameters whereas the Pareto–Lévy distribution has only three.     

Externality Policy Reform: A General Equilibrium Analysis

We characterize Pareto‐improving and equilibrium‐preserving policy reforms in a second‐best (Diamond/Mirrlees) world with a consumption externality. A counterintuitive finding is that, starting from an initial equilibrium with no direct quantity control on the externality, it is possible that all Pareto‐improving and equilibrium‐preserving directions of change require an increase in a negative externality. We provide intuition for these results by establishing a nexus between Guesnerie's approach to designing (tax) policy reforms and the standard Kuhn–Tucker technique for identifying the manifold of feasible Pareto‐optimal states, given the instruments available to the policy maker.     

Ambiguity aversion and trade

What is the effect of ambiguity aversion on trade? Although in a Bewley??s model, ambiguity aversion always leads to less trade; in other models, this is not always true. However, we show that if the endowments are unambiguous, then more ambiguity aversion implies less trade for a very general class of preferences. The reduction in trade caused by ambiguity aversion can be as severe as to lead to no trade. In an economy with MEU decision makers, we show that if the aggregate endowment is unanimously unambiguous, then every Pareto optima allocation is also unambiguous. We also characterize the situation in which every unanimously unambiguous allocation is Pareto optimal. Finally, we show how our results can be used to explain the home-bias effect. As a useful result for our methods, we also obtain an additivity theorem for CEU and MEU decision makers that does not require comonotonicity.     

A comparison of city size distributions for China and India from 1950 to 2010

We examine the distributions of Chinese and Indian city sizes for seven decades (1950s to 2010s) using lognormal, Pareto, and general Pareto distributions. We ascertain which distribution fits the data and how the city size distributions change during these periods. The Chinese city size distribution is represented by lognormal in the early periods (1950–1990) and by Pareto in 2010, but is not characterized by Zipf, which could be attributed to Chinese government’s restrictions of migration from rural to urban areas and the one-child policy. In contrast, the Indian city size distribution transitions from lognormal in the earlier periods to Zipf in the later periods.     

Efficiency and options on the market index

Summary. In a static exchange economy, when all the endowments are issued as securities on a stock exchange, Pareto optimal allocations may be reached by trading options on the market index (see Breeden and Litzenberger (1978)). We extend this result when some of the risks cannot be exchanged on the market. Options on an appropriate index, which typically differs from the market index, depending on the correlation of the non-tradable risks with the exchanged securities, are still an appropriate tool to support a (constrained) efficient equilibrium. This suggests that the recent development of derivatives based on interest rates may be an efficient way to reach a Pareto optimal allocation of risks. Received: June 16, 1997; revised version: July 25, 1997     

Intergenerational transfers and the social discount rate

This paper investigates the relationship between intergenerational asset transfers and the choice of the discount rate for use in cost-benefit analysis in a model of a competitive overlapping generations economy constrained by a socially managed exhaustible resource. Provided that there are no distortions in capital markets and that all agents hold perfect foresight, cost-benefit techniques will result in a Pareto efficient resource allocation if the discount rate is set equal to the market rate of interest. But since the path of the interest rate depends on the level of intergenerational transfers, cost-benefit techniques do not ensure a socially desirable distribution of welfare between generations; a social optimum will result only if intergenerational transfers are properly chosen and enforced. Decentralized private altruism may result in intergenerational transfers that both present and future individuals would agree are too small if members of the present generation attach positive weight to the general welfare of future generations, not simply their personal descendants. In a world where intergenerational transfers are non-optimal, second-best policy-making may imply a constrained optimum that is inefficient. Together, these findings suggest that cost-benefit analysis is at best a partial criterion to policy formulation that should be used only in conjunction with ethical principles that define the proper distribution of welfare between present and future generations.     

Pareto violations of parliamentary voting systems

It has been known for a long time that many binary voting rules can select a Pareto dominated outcome, that is an outcome such that there exists some other alternative which is preferred by every voter. In this paper, we show that some of these rules can select an outcome Pareto dominated in a much stronger sense. Furthermore, our main results are concerned with the evaluation of the likelihood of Pareto dominated outcomes under four social choice rules commonly used in Parliaments or in committees. Given a set of four alternatives and a set of n individuals, we assume anonymous profiles and using analytical methods we compute the proportion of profiles at which the Pareto criterion is violated. Our results show that one should not be especially worried about the existence of the possibility as such. We are grateful to two anonymous referees for very helpful remarks and suggestions.     

The veil of public ignorance

A theory of cooperative choice under incomplete information is developed in which agents possess private information at the time of contracting and have agreed on a utilitarian “standard of evaluation” governing choices under complete information. The task is to extend this standard to situations of incomplete information. Our first main result generalizes Harsanyi's (J. Polit. Econ. 63 (1955) 309) classical result to situations of incomplete information, assuming that group preferences satisfy Bayesian Coherence and Interim Pareto Dominance. These axioms are mutually compatible if and only if a common prior exists. We argue that this result partly resolves the impossibility of Bayesian preference aggregation under complete information.     

Coalitional Strategy-Proofness in Economies with Single-Dipped Preferences and the Assignment of an Indivisible Object

We study two allocation models. In the first model, we consider the problem of allocating an infinitely divisible commodity among agents with single-dipped preferences. In the second model, a degenerate case of the first one, we study the allocation of an indivisible object to a group of agents. Our main result is the characterization of the class of Pareto optimal and coalitionally strategy-proof allocation rules. Alternatively, this class of rules, which largely consists of serially dictatorial components, can be characterized by Pareto optimality, strategy-proofness, and weak non-bossiness (in terms of welfare). Furthermore, we study properties of fairness such as anonymity and no-envy. Journal of Economic Literature Classification Numbers: D63, D71.     

Non-constant Returns,Pareto Optimality and Competitive Equilibrium

Competitive equilibrium is not Pareto optimal if returns to scale are not constant, except in special and accidental circumstances. This result is demonstrated using a classical production model; it holds quite generally and independently of all other sources of Pareto inefficiency, such as externalities, imperfect information and quantity constraints. It establishes a general and ubiquitous basis for critique of the 'invisible hand' ideology, which still dominates both the textbooks and wider reaches of social thought.     

The Economics of Tenancy Rent Control

We consider a rent control regime where rent increases on, and eviction of, a sitting tenant are forbidden. When apartments become vacant landlords may negotiate new rents. If inflation exists, landlords prefer to rent to short-staying tenants. Since departure-date-contingent contracts are forbidden and landlords cannot tell whether tenants are short-stayers, an adverse selection problem arises, with a Pareto inefficient equilibrium. When tenant types are determined endogenously, multiple equilibria can arise where one equilibrium is Pareto dominated. Abolition of the rent control regime, cannot only shift the equilibrium out of this inferior outcome, but also result in across-the-board lowering of rents.     

An Allocation Rule with Wealth-Regressive Tax Rates

We introduce a public good allocation rule whose direct implementation by asking agents their endowments leads to Nash equilibrium outcomes—always Pareto dominating voluntary contributions outcomes. Although the Nash equilibrium allocations induced by this rule are not Pareto optimal in general, they are so in two-person economies.