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What is the Normal Rate of Convergence of the Core? (Part I)

Econometrica 1981 49(1), 73
[Agents are assumed to have smooth preferences with natural boundary conditions. For large regular economies, satisfying an indeconposability conditions, it is shown that core allocations and competitive allocations converge to each other with a rate inversely proportional to the number of agents m. To the extent that the indecomposability condition is harmless, 1/m can be regarded as the normal rate of convergence. However, if indifference surfaces are allowed to have kinks, 1/m cannot be regarded as normal. This is treated in Part II [6].]

Biases in Dynamic Models with Fixed Effects

Econometrica 1981 49(6), 1417
[It is well known from the Monte-Carlo work of Nerlove that using the standard within-group estimator for dynamic models with fixed individual effects generates estimates which are inconsistent as the number of "individuals" tends to infinity if the number of time periods is kept fixed. In this paper we present analytical expressions for these inconsistencies for the first order autoregressive case.]

Rational Expectations in Stationary Linear Models

Econometrica 1981 49(1), 171
Linear time series models have come to dominate the macroeconomic literature on rational expectations and equilibrium business cycle theory. But the explicit solution of such models has generally required strong restrictions upon the exogenous process of stochastic shocks (e.g., temporal independence) as well as upon the values of various demand and supply elasticities. This paper exhibits a solution technique, the method of z-transforms, which does not require one to impose such restrictions. The value of this method is illustrated by applying it to completely characterize the symmetric, stationary, rational expectations equilibria of a naive linear model of land speculation. This approach also permits systematic study of the informationally asymmetric equilibria of the model. THIS PAPER develops a method for analyzing rational expectations (RE) equilibria in linear economic models. The methods I shall discuss usually enable one to determine whether or not a given model has a RE equilibrium and, if one exists, to exhibit an explicit expression for the stochastic process of equilibrium prices. The techniques apply to linear models driven by stationary processes of exogenous random shocks.

What do Economists Know? An Empirical Study of Experts' Expectations

Econometrica 1981 49(2), 491
For more than three decades, economic columnist Joseph A. Livingston has canvassed a panel of economists twice a year, eliciting their six-month and twelve-month forecasts for more than a dozen key variables. This study analyzes whether experts' predictions are unbiased, and whether complete use was made of all relevant, known information (unbiasedness and completeness being necessary conditions for fully rational expectations). Little bias was found in either half-year or full-year predictions, but extensive underutilization of information-particularly data on monetary growth-occurred. To prophecy is extremely difficult-especially with respect to future. Chinese proverb Do ECONOMISTS' EXPECTATIONS regarding key price and nonprice variables utilize all known, relevant information, in an unbiased, efficient manner? This is a worthy subject for research, for several reasons. Properties of experts' predictions likely form an upper bound for those of laymen. Further, as John Muth [14] has noted, the character of dynamic processes is typically very sensitive to way expectations are influenced by actual course of (p. 316); hence, we need to know precisely how events do affect expectations. Finally, common practice of replacing a variable's (generally unobserved) expectation with a proxy based on its past values will be unbiased (and will not cause bias in other

Resource Allocation Under Asymmetric Information

Econometrica 1981 49(1), 33
[The purpose of this paper is to provide a method for characterizing efficient allocation processes and efficient allocations for a large class of environments in which asymmetric information is an important factor. This method is based on a rigorous application of statistical decision theory and makes explicit both the information available to agents ex ante and the way in which information is transmitted during any multistage allocation process.]

On the Asymptotic Bias of the Ordinary Least Squares Estimator of the Tobit Model

Econometrica 1981 49(2), 505
This paper presents a precise characterization of the bias of least squares in two limited dependent variable models, the Tobit model and the truncated regression model. For the cases considered, the method of moments can be used to correct the bias of OLS. For more general cases, the results provide approximations which appear to be relatively robust. 13, and o, . In this paper we present a precise characterization of that bias for the particular case in which xt, as well as -,, is normally distributed. We also show that the bias of the OLS slope estimator can be corrected by dividing each estimate by the sample proportion of nonlimit observations. Other structural parameters can be consistently estimated in a similar fashion. We present some evidence on the effect of nonnormality with respect to the predictions obtained in the normal model. The case in which the sample contains only nonlimit observation (the truncated regression model) is considered elsewhere (Olsen (7)). We analyze the relationship between his results and ours, and derive some predictions of the normal model with respect to the seriousness of truncation bias.

Testing For Unit Roots: 1

Econometrica 1981 49(3), 753
[This paper investigates the distribution of the least squares estimator of the coefficient α in the model @c"t = @a@c"t -"1 + @?"t where the @?"t where the @?"t are independently distributed N (O, @s extasciicircum2). The exact finite sample and limiting distributions are calculated when α ≥ 1 and finite sample distributions when α extless 1. These distributions are used to compute the power functions of tests of the random walk hypothesis α = 1 as well as the hypotheses.]

The Measurement of Deadweight Loss Revisited

Econometrica 1981 49(5), 1225
modities (such as various consumer goods and labor), M fixed factors (such as land, natural resources and various types of fixed capital), and a government which taxes commodities and fixed factors in order to finance various govern- ment expenditures. It is well known2 that if the government can raise its required revenue by taxing the fixed factors alone, then the resulting allocation of resources is Pareto optimal-no single household's utility or real income can be increased without decreasing the utility of some other household. Suppose we are at an initial equilibrium where government revenue is being raised by taxing the fixed factors alone. Then the resulting equilibrium can be rationalized by maximizing a certain weighted sum of utility functions subject to various feasibility constraints. Now think of the government replacing the taxes on fixed factors with distortionary commodity taxes. In Section 3, we calculate the second order directional derivative of the above weighted sum of utility functions with respect to any feasible direction of tax change, evaluated at the initial equilibrium which is Pareto optimal. Of course, the first order directional derivatives of the weighted sum of utility functions with respect to feasible directions of tax change are zero evaluated at this initial equilibrium. We obtain a measure of economic due to tax distortions which is virtually identical to that of Boiteux (3, p. 113) and which bears a resemblance to the dead loss of Hotelling (22, p. 254), the consumer's surplus measures of Hicks (19; 20, pp. 330-3), and the deadweight loss measure of Harberger (16, p. 61; 17, p. 788). In Section 4, we calculate a measure of welfare based on Debreu's (4, 5) coefficient of resource utilization (which is a modification of a measure of due to Allais (1, 2)) and we show that under certain conditions, the Hotelling,

Generic Existence of Completely Revealing Equilibria for Economies with Uncertainty when Prices Convey Information

Econometrica 1981 49(5), 1173
Conditions which imply the existence of strict rational expectations equilibria for most static pure exchange economies where prices convey information about the state of the world are analyzed. Information is aggregated and transmitted by prices because agents have different initial information and maximize the conditional expectation of state-dependent utility functions. Major results state that if, with probability one, agents' characteristics do not vary too much as the state of the world varies, then, generically, there exist equilibrium price functions which reveal all initial information. More precisely, if the support of the image measure is contained in a compact C1 manifold (satisfying some technical conditions) which is of sufficiently low dimension relative to the number of commodities, then existence of completely revealing equilibria is generic. Any economy satisfying these assumptions can be approximated by a sequence of economies which also obey these assumptions and have completely revealing equilibrium price functions. Slight perturbations do not destroy the existence property.