Knowledge that Transforms

This paper compares two different models in a common environment. The first model has liquidity constraints in that consumers save a single asset that they cannot sell short. The second model has debt constraints in that consumers cannot borrow so much that they would want to default, but is otherwise a standard complete markets model. Both models share the features that individuals are unable to completely insure against idiosyncratic shocks and that interest rates are lower than subjective discount rates. In a stochastic environment, the two models have quite different dynamic properties, with the debt constrained model exhibiting simple stochastic steady states, while the liquidity constrained model has greater persistence of shocks.

In interim economies with asymmetric information, we show that the coarse core of Wilson (1978) does not converge to price equilibrium allocations as the economy is replicated.This failure of core convergence is a basic consequence of asymmetric information and extends to any reasonable notion of either (interim) core or price equilibrium.

A new method is proposed for constructing confidence intervals in autoregressive models with linear time trend. Interest focuses on the sum of the autoregressive coefficients because this parameter provides a useful scalar measure of the long-run persistence properties of an economic time series. Since the type of the limiting distribution of the corresponding OLS estimator, as well as the rate of its convergence, depend in a discontinuous fashion upon whether the true parameter is less than one or equal to one (that is, trend-stationary case or unit root case), the construction of confidence intervals is notoriously difficult. The crux of our method is to recompute the OLS estimator on smaller blocks of the observed data, according to the general subsampling idea of Politis and Romano (1994a), although some extensions of the standard theory are needed. The method is more general than previous approaches in that it works for arbitrary parameter values, but also because it allows the innovations to be'-a martingale difference sequence rather than i.i.d .. Some simulation studies examine the finite sample performance.

Consider nonempty finite pure strategy sets S1,…,Sn, let S=S1×⋅⋅⋅×Sn, let Ω be a finite space of “outcomes,” let Δ(Ω) be the set of probability distributions on Ω, and let θ: S→Δ(Ω) be a function. We study the conjecture that for any utility in a generic set of n-tuples of utilities on Ω there are finitely many distributions on Ω induced by the Nash equilibria of the game given by the induced utilities on S. We give a counterexample refuting the conjecture for n≥3. Several special cases of the conjecture follow from well known theorems, and we provide some generalizations of these results.

The ready-to-eat cereal industry is characterized by high concentration, high price-cost margins, large advertising-to-sales ratios, and numerous introductions of new products. Previous researchers have concluded that the ready-to-eat cereal industry is a classic example of an industry with nearly collusive pricing behavior and intense nonprice competition. This paper empirically examines this conclusion. In particular, I estimate price-cost margins, but more importantly I am able empirically to separate these margins into three sources: (i) that which is due to product differentiation; (ii) that which is due to multi-product firm pricing; and (iii) that due to potential price collusion. The results suggest that given the demand for different brands of cereal, the first two effects explain most of the observed price-cost margins. I conclude that prices in the industry are consistent with noncollusive pricing behavior, despite the high price-cost margins. Leading firms are able to maintain a portfolio of differentiated products and influence the perceived product quality. It is these two factors that lead to high price-cost margins.

In the common agency problem multiple mechanism designers simultaneously attempt to control the behavior of a single privately informed agent.The paper shows that the allocations associated with equilibria relative to any ad hoc set of feasible mechanisms can be reproduced as equilibria relative to (some subset of) the set of menus.Furthermore, equilibria relative to the set of menus are weakly robust in the sense that it is possible to ¯nd continuation equilibria so that the equilibrium allocations persist even when the set of feasible mechanisms is enlarged.

This paper establishes a general form of the "payoff equivalence" result in mechanism design theory: under certain conditions, the utility of any type in an incentive-compatible mechanism is determined up to an additive constant by the allocation rule alone. When types are single-dimensional the result is well known (see, for instance, Myerson (1981)). When types are multi-dimensional the result follows from the Fundamental Theorem of Calculus once sufficient smoothness is assumed. We obtain a more general result by using an extension of the Fundamental Theorem to nonsmooth convex functions and more generally, to the class of regular Lipschitzian functions.

We study a two-period model where ex ante inferior choice may tempt the decision-maker in the second period. Individuals have preferences over sets of alternatives that represent second period choices. Our axioms yield a representation that identifies the individual's commitment ranking, temptation ranking, and cost of self-control. An agent has a preference for commitment if she strictly prefers a subset of alternatives to the set itself. An agent has self-control if she resists temptation and chooses an option with higher ex ante utility. We introduce comparative measures of preference for commitment and self-control and relate them to our representations.

The goal of this paper is to provide a comprehensive empirical analysis of majority rule and Tiebout sorting within a system of local jurisdictions. The idea behind the estimation procedure is to investigate whether observed levels of public expenditures satisfy necessary conditions implied by majority rule in a general equilibrium model of residential choice. The estimator controls for observed and unobserved heterogeneity among households, observed and unobserved characteristics of communities, and the potential endogeneity of prices and expenditures, as well as the self-selection of households into communities of their choice. We estimate the structural parameters of the model using data from the Boston Metropolitan Area. The empirical findings reject myopic voting models. More sophisticated voting models based on utility-taking provide a potential explanation of the main empirical regularities.