Non-myopic learning in differential information economies: the core

Summary. We study the process of learning in a differential information economy, with a continuum of states of nature that follow a Markov process. The economy extends over an infinite number of periods and we assume that the agents behave non-myopically, i.e., they discount the future. We adopt a new equilibrium concept, the non-myopic core. A realized agreement in each period generates information that changes the underlying structure in the economy. The results we obtain serve as an extension to the results in Koutsougeras and Yannelis (1999) in a setting where agents behave non-myopically. In particular, we examine the following two questions: 1) If we have a sequence of allocations that are in an approximate non-myopic core (we allow for bounded rationality), is it possible to find a subsequence that converges to a non-myopic core allocation in a limit full information economy? 2) Given a non-myopic core allocation in a limit full information economy can we find a sequence of approximate non-myopic core allocations that converges to that allocation? Received: May 25, 1999; revised version: August 9, 1999     

Robustness of sunspot equilibria

Summary. A sunspot equilibrium (SSE) is based on some extrinsic randomizing device (RD). We analyze the robustness of SSE. (1) We say that an SSE allocation is robust to refinements if it is also an SSE allocation based on any refinement of its RD. (2) We introduce two core concepts for analyzing the robustness of SSE in the face of cooperative-coalition formation. In the first, the blocking allocations are based on the RD that defines the SSE. In the second (stronger) core concept, coalitions select their own RDs. For the convex economy with restricted market participation, SSE allocations are robust under each of the definitions and the cores converge on replication of the economy to the set of SSE allocations. For the economy with an indivisible good, SSE allocations are not always robust. We provide examples of each of the following: (i) an SSE allocation that is not robust to refinement, (ii) an SSE allocation that is in neither core, (iii) an SSE allocation that is in the first core, but not in the second, and (iv) a core that does not converge upon replication to the set of SSE allocations. Received: July 31, 1995; revised version August 30, 1996     

Contractual distortions in a market with frictions

This paper analyses contract design in a decentralized market environment with frictions. While principals (e.g., firms) have all contractual power, their market power is constrained as agents (e.g., workers) can choose to wait and search for better offers. We find that results depend crucially on how market frictions affect agents’ utilities. With type-independent costs of search and waiting, equilibrium contracts are always first-best. If agents are impatient and discount future payoffs, however, distortions vanish only gradually. In the latter case, we also characterize equilibrium offers and show that the market exhibits two types of externalities, both of which are absent in the case of type-independent costs of search.     

Finite Horizons,Political Economy,and Growth

This paper analyzes the political economy of growth when agents and the government have finite horizons and equilibrium growth is inefficient. A “representative” government (i.e., one whose preferences reflect those of its constituents) endowed merely with the ability to tax and transfer can improve somewhat on the market allocation, but cannot achieve first-best growth. Efficiency requires in addition the ability to bind future governments. We argue that this ability is related to political stability, and we provide empirical evidence that stability and growth-related policies (namely education) are meaningfully related. Journal of Economic Literature Classification Numbers: D9, H3, O5.     

UNIVERSALISM AND THE VALUE OF POLITICAL POWER

Although legislatures typically use majority rule to allocate a budget in distributive legislation, unanimous consent over the broad allocation of benefits is pervasive. I develop a game‐theoretic model where members strategically interact in a universal coalition to determine allocations, with noncooperative bargaining as a threat point for the breakdown of cooperation. To quantify the effects of political power on the agreed‐upon allocation, I structurally estimate the model using the “Bridge Bill Capital Budget” in 1992. I find that 16.73% of the budget would be allocated differently if allocations were determined only based on actual needs.     

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.     

Core is manipulable via segmentation

Any allocation rule that picks only core allocations is manipulable via segmentation. That is, there exists an economy with a coalition of agents such that, once this coalition splits momentarily from the rest of the economy and institutes the allocation rule within itself, no matter which individually rational sub-allocation the complementary coalition picks, when we paste all the agents back together at their new endowments and apply the allocation rule to this “collage” economy, each member of the former coalition will be strictly better off than under direct application of the allocation rule to the original economy.     

Fair allocations of a renewable resource

In an economy with finitely many agents, one renewable resource, and an infinite horizon, it is shown that there is exactly one maximal allocation corresponding to given limiting shares of consumption and this allocation converges monotonically. Therefore, if there is no discounting, at most one fair maximal program exists—that which gives an equal amount to each individual in the limit. In this allocation, envy is always finite. However, only in special cases is it envyfree. This is in contrast to the case of finite economies where envy-free and Pareto efficient allocations may not exist or, if they exist, may not be unique.     

Wage bargaining, labor-tax progression, and welfare

This paper analyzes the effect of labor-tax progression on employment and welfare in an economy with a unionized labor market. The government influences wage bargaining through its tax policies. Wages can be reduced by increasing the marginal labor-tax rate. If there are no restrictions on profit taxation, a first-best optimum with full employment is realized; this first-best optimum can always be implemented by a progressive tax schedule. If profit taxation is restricted, unemployment may arise. For this case, we show that the welfare-maximizing degree of tax progression is influenced by a variety of factors, in particular the wage elasticity of labor demand, the distribution of bargaining power, and the existence of unemployment benefits. Examples are given for both progressive and regressive tax structures. Comparative-static analysis reveals that a decline in union bargaining power, an increase in unemployment benefits, and an increase in the overall work force reduce the efficient degree of tax progression.     

On the core and Walrasian expectations equilibrium in infinite dimensional commodity spaces

In this paper, we establish two different characterizations of Walrasian expectations allocations by the veto power of the grand coalition in an asymmetric information economy having finitely many agents and states of nature and whose commodity space is a Banach lattice. The first one deals with Aubin non-dominated allocations, and the other claims that an allocation is a Walrasian expectations allocation if and only if it is not privately dominated by the grand coalition, by considering perturbations of the original initial endowments in precise directions.     

Pension,possible phaseout,and endogenous fertility in general equilibrium

The rich literature on Pay-As-You-Go (PAYG)-type pensions provides a notion that when pension return is dominated by the market return, generally it is impossible to phase pension out without hurting any generation. We show that PAYG pensions can indeed be phased out in a much richer framework where fertility is endogenous and general equilibrium effects are present. Interestingly, the factor that helps us to phase the pension out in a Pareto way is hidden in the structure of PAYG pension itself. Individualistic agents fail to recognize the benefits of their fertility decision on these programs and, therefore, end up in an allocation that is strictly dominated by the allocations that internalize this externality. Exploiting this positive externality, competitive economy can improve its allocations and can reach the planner's steady-state in finite time where each generation secures as much utility as in the competitive equilibrium. Clearly, it is possible to transition in a Pareto way to an economy either with no pension or with pensions whose return is not dominated by market return.     

The role of independence in the Green-Lin Diamond-Dybvig model

Green and Lin study a version of the Diamond-Dybvig model with a finite number of agents, independence (independent determination of each agent's type), and sequential service. For special preferences, they show that the ex ante first-best allocation is the unique equilibrium outcome of the model with private information about types. Via a simple argument, it is shown that uniqueness of the truth-telling equilibrium holds for general preferences—and, in particular, for a constrained-efficient allocation whether first-best or not. The crucial assumption is independence.     

Aid allocation rules

This paper studies an aid allocation rule used by major development agencies, and investigates optimal allocations when recipients are neoclassical economies undergoing transition dynamics. When recipients face aid absorption constraints, allocations that favor poorer recipients are not always optimal, contrary to what is assumed in assessments of donor performance. The most quantitatively significant factors that determine the optimal sensitivity to recipient characteristics are the generosity of the aid budget and the extent of absorption constraints. In neoclassical recipients, aid can only accelerate growth where there is already growth, so the optimal rule places little weight on growth and optimality is largely a matter of balancing recipient need against absorption constraints.     

Credibility and endogenous societal discounting

We consider a dynamic moral hazard economy inhabited by a planner and a population of privately informed agents. We assume that the planner and the agents share the same discount factor, but that the planner cannot commit. We show that optimal allocations in such settings solve the problems of committed planners who discount the future less heavily than agents. Thus, we provide micro-foundations for dynamic moral hazard models that assume a societal discount factor in excess of the private one. We extend the analysis to allocations that are reconsideration-proof in the sense of Kocherlakota [Kocherlakota, N., 1996. Reconsideration-proofness: A refinement for infinite horizon time inconsistency. Games and Economic Behavior 15, 33–54]. We show that these allocations solve the choice problem of a committed planner with a unit discount factor.     

Contract renegotiation in a continuous state space

Summary. When players are unable to write complete state contingent contracts it is shown, within the context of a non-cooperative contracting-renegotiation game, that the only subgame perfect equilibrium allocations are those that correspond to the set of first-best allocations. Players are able to implement this set of allocations by signing an initial contract that is subsequently renegotiated in all states of the world. The contracting-renegotiation problem is complicated in an interesting way by assuming that the state space is continuous. The issue of the existence of an initial contract, that is subsequently renegotiated to the set of first-best allocations, must be resolved. Unlike Aghion, Dewatripont and Rey [1994], the results here do not require nor depend upon the comonotonicity of the objective functions. Received: January 27, 1995; revised version July 1, 1996     

Optimal taxation with joint production of agriculture and rural amenities

We show that, when there is joint production of an agricultural good and rural amenities, the first-best allocation of resources can be implemented with a tax on the agricultural good and some subsidies on the production factors (land and labor). The use of a subsidy on the agricultural good can only be explained by the desire of the policymaker to redistribute income from the consumers to the farmers.     

On the optimality of optimal income taxation

The Mirrleesian model of income taxation restricts attention to simple allocation mechanism with no strategic interdependence, i.e., the optimal labor supply of any one individual does not depend on the labor supply of others. It has been argued by Piketty (2009) [12] that this restriction is substantial because more sophisticated mechanisms can reach first-best allocations that are out of reach with simple mechanisms. In this paper, we assess the validity of Piketty?s critique in an independent private values model. As a main result, we show that the optimal sophisticated mechanism is a simple mechanism, or, equivalently, a Mirrleesian income tax system.     

Efficiency and equilibrium when preferences are time-inconsistent

We consider an exchange economy with time-inconsistent consumers whose preferences are additively separable. If consumers have identical discount factors, then allocations that are Pareto efficient at the initial date are also renegotiation-proof. In an economy with a sequence of markets, competitive equilibria are Pareto efficient in this sense, and for generic endowments, only if preferences are locally homothetic.     

A utilitarian approach to the provision and pricing of excludable public goods

This paper studies utilitarian welfare maximization in a large economy with an excludable public good where individual preferences are private information. If inequality aversion is large, optimal allocations involve the use of admission fees and exclusion to redistribute resources from people who benefit a lot from the public good to people who benefit little. If inequality aversion is close to zero, optimal admission fees are zero. Because of inequality aversion, information rents of people who benefit a lot from the public good receive less weight, so optimal provision levels for the public good are below first-best levels.     

Public-Good Provision with Many Participants

For a nonexcludable public good with benefit and cost functions independent of the number of participants, this paper studies second-best allocations under Bayesian interim incentive compatibility and interim individual rationality. As the number of participants becomes large, second-best provision levels converge in distribution to first-best levels if the latter are bounded. Second-best provision levels become large in absolute terms but small relative to first-best levels if benefit and cost functions are isoelastic. In contrast, for an excludable public good, the ratio of second-best to first-best levels is bounded away from zero.