John Leahy

Psychological Expected Utility Theory and Anticipatory Feelings

We extend expected utility theory to situations in which agents experience feelings of anticipation prior to the resolution of uncertainty. We show how these anticipatory feelings may result in time inconsistency. We provide an example from portfolio theory to illustrate the potential impact of anticipation on asset prices.

Monetary policy and asset prices

Abstract The first part of this paper surveys the literature on asset prices and monetary policy. We then consider the appropriate policy response to two types of shocks that are associated with how asset prices affect the economy. The first set of shocks are the ones whose primary impact lies in the future. These shocks affect the economy and asset prices through expectations of future growth. The second set are shocks to net worth which directly impact the ability of firms to borrow and for consumers to lend.

State-Dependent Pricing and the Dynamics of Money and Output

Standard macroeconomic models of price stickiness assume that each firm leaves its price unchanged for a fixed amount of time. We present an alternative model in which the pricing decision depends on the state of the economy. We find a method of aggregating individual price changes that allows a simple characterization of macroeconomic variables. The model produces a positive money-output correlation and an empirical Phillips curve. In addition, the impact of monetary shocks depends crucially on the current level of output, which points to a natural connection between state-dependent microeconomics and state-dependent macroeconomics.

Investment in Competitive Equilibrium: The Optimality of Myopic Behavior

There is an extensive literature on the optimal irreversible investment strategy of a solitary firm facing an exogenous price process. This paper shows that the investment strategies that this literature derives may be optimal in competitive equilibrium even though the price process is now endogenous. This provides a simple means for computing equilibrium investment strategies.

AGGREGATION AND OPTIMIZATION WITH STATE-DEPENDENT PRICING

The literature on the aggregation of (S,s) policies has generally ignored the impact of aggregates on individual decisions. In the case of pricing, the feedback effects are clear. Not only do pricing strategies determine the evolution of the price level, the evolution of the price level influences pricing strategies. The authors provide a consistent treatment of aggregation and optimization and study three issues in the pricing literature: the relationship between strategic complementarity and the real effects of money; the relationship between the variance of money and the correlation between money and output; and the relationship between the cost and size of price adjustment.

Miracle on Sixth Avenue: Information Externalities and Search

After a long dormant period, lower Sixth Avenue in New York has undergone a rapid revitalization. The authors show that a simple search theoretic model with information spillovers can explain both the period of underuse and the rapid turnaround. The model reduces to a simple equation, which allows them to do comparative statics on the duration of vacancies. The authors show how the solution reacts to changes in market structure and changes in search technology. The model is suggestive of difficulties that may occur in many markets in which there are changes over time in the optimal use of resources.

The Supply of Information by a Concerned Expert

How much information should a policy maker pass on to an ill-informed citizen? In this paper, we address this classic question of Crawford and Sobel (1982) in a setting in which beliefs impact utility, as in Kreps and Porteus (1978). We show that this question cannot be answered using a utility function with standard revealed preference foundations. To solve the model, we go beyond the classical model in two respects, relying on the psychological expected utility model of Caplin and Leahy (2001) to capture preferences, and the psychological game model of Geanakoplos et al. (1989) to capture strategic interactions.

Sectoral Shocks, Learning, and Aggregate Fluctuations

We present a model in which sectoral shocks have aggregate consequences. The model relies on irreversible investment and imperfect information to slow the adjustment of expanding industries. We show that this gradual expansion is sub-optimal.

The recursive approach to time inconsistency

We introduce a new class of finite horizon stochastic decision problems in which preferences change over time, and provide a proof of the existence of a recursively optimal strategy. Recursive optimization techniques dominate many areas of economic dynamics. However, in decision problems in which tastes change over time, the solution technique most commonly applied is not recursive, but rather strategic (subgame perfection). In this paper we argue in favor of the recursive approach, and we take the necessary theoretical steps to make the recursive methodology applicable.

The Economics of Adjustment

In this paper we argue that many topics in macroeconomics can be viewed as part of the broader theory of the economics of adjustment. We argue that existing approaches to the economics of adjustment take a very narrow view of the role of information. We outline an approach to this topic that stresses the role of learning and information externalities, and discussed through examples how these concerns alter the qualitative nature of the adjustment process. In particular, there appears to be a general bias towards the underprovision of information in a variety of settings which leads to inefficient adjustment.