Knowledge that Transforms

Asymptotic distributions are derived for the ordinary least squares estimate of a first order autoregression model when the series is fractionally integrated. The fractional unit root distribution is introduced to describe the limiting distribution. The unit root distribution is shown to be an atypical member of this family because its density is nonzero over the entire real line. For -1/2

We analyze a model of optimal consumption and portfolio selection in which consumption services are generated by holding a durable good. The durable good is illiquid in that a transaction cost must be paid when the good is sold. It is shown that optimal consumption is not a smooth function of wealth; it is optimal for the consumer to wait until a large change in wealth occurs before adjusting his consumption. As a consequence, the consumption based capital asset pricing model fails to hold. Nevertheless, it is shown that the standard, one factor, market portfolio based capital asset pricing model does hold in this environment. It is shown that the optimal durable level is characterized by three numbers (not random variables), say x, y, and z (where x

The paper presents a simple pairwise meetings model of trade.The new feature is that agents have asymmetric information about the true state of the world.The focus is on the transmission of the information through the process of trade.The qualitative questions is: to what extent is the information revealed to uninformed agents through the trading process, when the market is in some sense frictionless?In particular: does the decentralized process give rise to full revelation results as derived by the literature on rational expectations for centralized and competitive environments?In the context of the model of this paper, it turns out that the information is not fully revealed to uninformed agents, even when the market is in some sense approximately frictionless.

A new definition of strategic stability is shown to satisfy all of the requirements given by Elon Kohlberg and Jean-Francois Mertens (1986). The definition follows the general form of the original definition of Kohlberg and Mertens, but, rather than working with perturbations of the payoffs or strategy space, works directly with perturbations to the best reply correspondence. With the appropriate topology on this space of perturbations, the resulting definition does satisfy all of the requirements given by Kohlberg and Mertens. It is shown that one does not have much freedom in the topology one uses.

The paper develops a model of retirement based on the option value of continuing to work.Continuing to work maintains the option of retiring on more advantageous terms later.The model is used to estimate the effects on retirement of firm pension plan provisions.Typical defined benefit pension plans in the United States provide very substantial incentives to remain with the firm until some age, often the early retirement age, and then a strong incentive to leave the firm thereafter.(This may be a major reason for the rapidly declining labor force participation rates of older workers in the United States.)The model fits firm retirement data very well; it captures very closely the sharp discontinuous jumps in retirement rates at specific ages.The model is used to simulate the effect on retirement of potential changes in pension plan provisions.Increasing the age of early retirement from 55 to 60, for example, would reduce firm departure rates between ages 50 and 59 by almost forty percent.

The author builds a theory of the choice of techniques in joint production, at a given profit rate, considering a market algorithm. Partial results are extended by means of an abstract notion of technology, where techniques meet demand and satisfy local properties. Global results on the existence, uniqueness, and convergence towards an equilibrium technique are obtained. The author, thus, characterizes cases where a square technique is reached, which provides an answer to an old debate, initiated by W. S. Jevons, between classical and neoclassical economists. But the framework allows for a more general interpretation in terms of two-level planning procedures.

Individuals with finite private information independently choose acts and messages. Their utilities may depend on all acts and information, including the center's. Incentive payments are separable and fully transferable. Implementable incentives making specified behavior a Bayesian equilibrium are derived whenever the center's information depends stochastically, however slightly, on all relevant private information, and also whenever individuals' relative valuations of acts, however divergent, are not too dissimilarly affected by different states of nature. Feasibility is resolved whenever the desired strategies reveal the agents' beliefs about the center's information. Key concepts of agent similarity are developed for nonresponsive and budget-balancing cases.

Seiji Nabeya, Katsuto Tanaka, A General Approach to the Limiting Distribution for Estimators in Time Series Regression with Nonstable Autoregressive Errors, Econometrica, Vol. 58, No. 1 (Jan., 1990), pp. 145-163

This paper reports on an experimental study of-the way in which individuals make inferences from publicly available information. We compare the predictions of a theoretical model of a common knowledge inference process with actual behavior. In the theoretical model, "perfect Bayesians," starting with private information, take actions; an aggregate statistic is made publicly available; the individuals do optimal Bayesian updating and take new actions; and the process continues until there is a common knowledge equilibrium with complete information pooling. We find that the theoretical model roughly predicts the observed behavior, but the actual inference process is clearly less efficient than the standard of the theoretical model, and while there is some pooling, it is incomplete.