Cultural Transmission, Marriage and the Evolution of Ethnic and Religious Traits

Cultural Transmission; marriage

Decentralizing Incentive Efficient Allocations of Economies with Adverse Selection

We study competitive economies with adverse selection and fully exclusive contractual relationships. We consider economies where agents are privately informed over the probability distribution of their endowments, and trade to insure against this uncertainty. As in Prescott-Townsend (1984), we model exclusivity by imposing the incentive compatibility constraints directly on the agents' consumption possibility set. In this set-up, we identify the externality associated with the presence of adverse selection as a special form of consumption externality. We consider a structure of markets which allows to internalize such externality, for which we show that competitive equilibria exist and are incentive efficient. On the other hand, when this 'expanded' set of markets required to internalize such externality does not exist, competitive equilibria are shown to be, typically, not incentive efficient, but to satisfy an appropriately defined notion of third best efficiency. Appropriate versions of the second welfare theorem for these two market structures are also established.

General Competitive Analysis with Asymmetric Information

This paper studies competitive equilibria in economies characterized by the presence of asymmetric information (both of the moral hazard and the adverse selection type). We consider economies where non-exclusive contracts (securities) with payoffs dependent on the agents' private information are traded on competitive markets. It is shown that the existence of competitive equilibria is not guaranteed under the dame set of assumptions as with symmetric information.ASYMETRIC INFORMATION ; ECONOMIC EQUILIBRIUM

The distribution of wealth and redistributive policies

In this paper we study theoretically the dynamics of the distribution of wealth in an Overlapping Generation economy with bequest and various forms of redistributive taxation. We characterize the transitional dynamics of the wealth distribution and as well as the stationary distribution. We show that, in our economy, the stationary wealth distribution is a power law, a Pareto distribution in particular. Wealth is less concentrated (the Gini coefficient is lower) for both higher capital income taxes and estate taxes, but the marginal effect of capital income taxes is much stronger than the effect of estate taxes. Finally, we characterize optimal redistributive taxes with respect to an utilitarian social welfare measure. Social welfare is maximized short of minimal wealth inequality and with zero estate taxes.wealth distribution

Government Intervention as an Optimal Response to Government (not Market!) Failure

This paper provides a theory of government intervention, such as government ownership, regulation, mandatory public schooling, subsidies, and industrial policy, as an optimal policy response due to the inability to commit not to expropriate private investment or bail agents out. If the government cannot commit not to expropriate the capital of private firms expost, private firms may not invest ex ante. The government may hence need to undertake investment itself. Thus, government ownership may be optimal, and, indeed, may be optimal even if government owned firms are less efficient. Public enterprise as a remedy for lack of private investment due to the threat of expropriation by the government should be particularly important in capital intensive sectors such as manufacturing, extraction of natural resources, and services which require large infrastructure investments, which is consistent with the data. Similarly, if the government bails out households which do not invest in schooling or save for retirement ex post, the government has to enforce universal schooling and force agents to save through social security systems ex ante. Government intervention may thus primarily be a response to government failure rather than market failurePublic enterprise, time inconsistency, optimal policy

Efficient Competitive Equilibria with Adverse Selection

Do Walrasian markets function orderly in the presence of adverse selection? In particular, is their outcome efficient? This paper addresses these questions in the context of a Rothschild and Stiglitz insurance economy. We identify an externality associated with the presence of adverse selection as a special form of consumption externality. Consequently, we show that while competitive equilibria always exist, they are not typically incentive efficient. However, as markets for pollution rights can internalize environmental externalities, markets for consumption rights can be designed so as to internalize the consumption externality due to adverse selection. With such markets competitive equilibria exist and are always incentive efficient. Moreover, any incentive efficient allocation can be decentralized as a competitive equilibrium.

Procrastination, self-imposed deadlines and other commitment devices

In this paper we model a decision maker who must exert costly effort to complete a single task by a fixed deadline. Effort costs evolve stochastically in continuous time. The decision maker will then optimally wait to exert effort until costs are less than a given threshold, the solution to an optimal stopping time problem. We derive the solution to this model for three cases: (1) time consistent decision makers, (2) naıve hyperbolic discounters and (3) sophisticated hyperbolic discounters. Sophisticated hyperbolic discounters behave as if they were time consistent but instead have a smaller reward for completing the task. We show that sophisticated decision makers will often self-impose a deadline to ensure early completion of the task. Other forms of commitment are also discussed.Procrastination; Hyperbolic Discounting; Time Consistency