Knowledge that Transforms

Generally, structural job search models are taken to be stationary. In this paper models are examined in which every exogenous variable can cause nonstationarity, for instance because its value is dependent on unemployment duration. A general differential equation that describes the evolution of the reservation wage over time is derived. As an empirical illustration a nonstationary structural model is estimated that focuses on the consequences of a downward shift in the level of benefits. It appears that the elasticity of duration with respect to the level of benefits after the shift is much larger than the elasticity with respect to the level before the shift.

The article develops new approximations to the distribution function of a general econometric estimator or test statistic from a linear model. The method relies heavily on the general arguments for the validity of Edgeworth approximations, and produces formulae of a similar type, except that, instead of using the cumulative normal distribution, an Imhof distribution is used derived from the exact distribution of a linear combination of the sample data second moments. On theoretical grounds this might be expected to give better approximations for some estimators. In practice comparisons were made between computed approximations of both types for several simple cases.

A yes or no decision must be made about some issue. All agents must agree. The “Coase Theorem” asserts that the efficient outcome will always result. Suppose the value (positive or negative) that an individual attaches to an affirmative decision is privately known to that individual. It is proved, under very mild conditions, that with independent types, as the number of agents increases, the probability of an affirmative efficient decision goes to zero. An example in which it is common knowledge that an affirmative decision is efficient and yet the probability of such a decision goes to zero is given.

The primal-dual methodology of Samuelson (1965) is extended and applied to a nonautonomous variational calculus problem with a fixed vector of initial stocks, fixed initial and terminal time values, a free vector of terminal stocks, and a time-independent vector of parameters. It is shown that if the solution of the variational problem is smooth enough, the qualitative effects of parameter perturbations on the entire optimal arcs can be represented by a generalized Slutsky-type matrix, which holds in integral form and is symmetric negative semidefinite. Sufficient conditions for the optimal value function to be convex in the parameters are also given.

This paper characterizes the monetary equilibria of an economy with commodity and labour contracts. If government policy is not “too variable,” there may exist an equilibrium with predetermined wages and prices. In this equilibrium, observed changes in the money supply to finance government purchases have persistent real effects. The paper also provides theoretical support for an inverse relationship between the degree of indexation in contracts and the persistence of policy effects.

This paper shows that if the difference of two positive semidefinite matrices is positive semidefinite then the difference of their generalized inverses is negative semidefinite. It uses this to compare comparative static behaviour over feasible sets whose distance functions have Hessians with a positive semidefinite difference. It then interprets this condition in terms of various ideas of the relative convexity of the two sets and relates it to the Le Chatelier principle.

This paper develops new empirical models of market concentration from game-theoretic models of entry. We construct our models from inequality conditions that describe entrants' equilibrium strategies in simultaneous-move and sequential-move games, and use them to study the effects of entry in isolated monopoly markets for new automobiles. From estimates of the market size necessary to support one and two dealers, we conclude that monopoly dealers do not block the entry of a second dealer. We also find that entry does not cause price-cost margins to fall by much.

We analyze the problem in which agents have non-public information and are to play an asymmetric information game. The agents may reveal some or all of their information to other agents prior to playing this game. Revelation is via exogenously specified certifiable statements. The equilibria resulting from various revelation strategies are used to determine equilibrium revelation of information. Sufficient conditions are provided for complete revelation of all private information. A number of examples are provided illustrating when revelation will or will not occur in commonly analyzed games.

As was shown by Dewatripont, optimal long-term contracts under asymmetric information are generally not time-consistent. This paper fully characterizes the equilibrium of a two-period procurement model with commitment and renegotiation. It also analyzes whether renegotiated long-term contracts yield outcomes resembling those under either unrenegotiated long-term contracts or a sequence of short-term contracts, and links the analysis with the multiple unit durable good monopoly problem.

Journal Article Household Equivalence Scales: Comment Get access Daniel Leonard Daniel Leonard University of New South Wales Search for other works by this author on: Oxford Academic Google Scholar The Review of Economic Studies, Volume 57, Issue 2, April 1990, Pages 325–327, https://doi.org/10.2307/2297385 Published: 01 April 1990 Article history Received: 01 June 1988 Accepted: 01 June 1989 Published: 01 April 1990