[This paper deals with the optimal design of resource allocation mechanisms in the presence of asymmetric information. A buyer's valuation function is allowed to depend on the characteristics of other buyers as well as his own and sufficient conditions are provided under which the seller can extract the full surplus from the buyers in an "ex post Nash" equilibrium. The result is then applied to the important problem of optimal auction design.]
When charitable contributions are tax deductible, the marginal price of charitable giving in other consumption foregone per dollar of contributions is generally less than unity. Further, if the income tax schedule is a progressive step function, the marginal price of contributions is generally a rising step function of the level of contributions. The problem of estimating a contributions demand function for individuals is therefore complicated by the spurious correlation between the level of contributions and the observed marginal price. We take this econometric problem into account in estimating a contributions demand function using data from the 1972-73 Consumer Expenditure Survey. After comparing our results with those of estimation techniques used by other authors, we provide evidence on the impacts of alternative tax policies on charitable giving using our estimates of the model parameters.
This paper uses an intertemporal general equilibrium asset pricing model to study the term structure of interest rates. In this model, anticipations, risk aversion, investment alternatives, and preferences about the timing of consumption all play a role in determining bond prices. Many of the factors traditionally mentioned as influencing the term structure are thus included in a way which is fully consistent with maximizing behavior and rational expectations. The model leads to specific formulas for bond prices which are well suited for empirical testing. 1. INTRODUCTION THE TERM STRUCTURE of interest rates measures the relationship among the yields on default-free securities that differ only in their term to maturity. The determinants of this relationship have long been a topic of concern for economists. By offering a complete schedule of interest rates across time, the term structure embodies the market's anticipations of future events. An explanation of the term structure gives us a way to extract this information and to predict how changes in the underlying variables will affect the yield curve. In a world of certainty, equilibrium forward rates must coincide with future spot rates, but when uncertainty about future rates is introduced the analysis becomes much more complex. By and large, previous theories of the term structure have taken the certainty model as their starting point and have proceeded by examining stochastic generalizations of the certainty equilibrium relationships. The literature in the area is voluminous, and a comprehensive survey would warrant a paper in itself. It is common, however, to identify much of the previous work in the area as belonging to one of four strands of thought. First, there are various versions of the expectations hypothesis. These place predominant emphasis on the expected values of future spot rates or holdingperiod returns. In its simplest form, the expectations hypothesis postulates that bonds are priced so that the implied forward rates are equal to the expected spot rates. Generally, this approach is characterized by the following propositions: (a) the return on holding a long-term bond to maturity is equal to the expected return on repeated investment in a series of the short-term bonds, or (b) the expected rate of return over the next holding period is the same for bonds of all maturities. The liquidity preference hypothesis, advanced by Hicks [16], concurs with the importance of expected future spot rates, but places more weight on the effects of the risk preferences of market participants. It asserts that risk aversion will cause forward rates to be systematically greater than expected spot rates, usually
IN THIS PAPER we present a weighted-instrumental-variables estimator that is resistant2 to heavy-tailed errors, aberrant data in either the endogenous or exogenous variables, and certain other model failures. The estimator is analogous to the weighted-least-squares approach to robustness proposed by Krasker and Welsch [21] for ordinary regression. We will discuss the theory that motivated this estimator, derive some of its properties, describe our computational algorithm, and, using an empirical example, illustrate the estimator's utility as a tool for data analysis in structural models. The evolution of robust estimators for simultaneous-equations models has closely resembled the development of robust methods for ordinary regression. In both cases, research focused at first on the well-documented effects of long-tailed error distributions on the classical procedures. For ordinary regression models, statisticians have studied the properties of least-absolute-deviations (LAD) estimators (see Bassett and Koenker [2] and Amemiya [1]) and maximum-likelihood-type estimators (called M-estimators; see Huber [14]). For simultaneous-equations models, LAD can be generalized in several different ways to modify two-stage least squares or instrumental variables; Amemiya [1] has presented these estimators in a unified framework, and Powell [31] has proven their asymptotic normality under weak assumptions. Fair [8] has compared two-stage LAD estimates of a U.S. macroeconomic model with two-stage least squares and full-information maximum likelihood estimates. The M-estimator concept can also be generalized to simultaneous equations. For example, Prucha and Kelejian [32] have considered maximum-likelihood estimation under the assumption that the disturbance vector is multivariate student t. Although LAD and M-estimators maintain a high efficiency when the error distribution is heavy-tailed, they are not robust in the stronger sense of Hampel [10] which, roughly speaking, requires an estimator to have a limited sensitivity to any small fraction of the data.3 LAD and M-estimators fail under this criterion because a single observation whose values for the right-side variables are highly anomalous can have an arbitrarily large effect on LAD estimates or M-estimates, just as on the classical procedures. Consequently, these estimators do not provide insurance against the sort of gross errors that occur in some data sets; nor do they serve as reliable diagnostics for departures from linearity occurring in extreme regions of the space of right-side variables. For linear models, the estimators that satisfy the strong Hampel robustness criterion have become known as bounded-influence estimators. Several such estimators have been
[We study the problem of optimal pricing for a bundle of services characterized by two attributes (e.g., quantity and quality) and subject to capacity limitations or peakloading. An application is to services that take the form of a load-duration curve. Using separability assumptions on the demand and cost functions, we derive the optimal pricing policy for a monopolist seller. An example is solved completely.]
Etude d'un jeu de negociation strategique sequentiel avec information incomplete. Caracterisation d'une classe d'equilibres sequentiels appeles equilibres sequentiels de negociation et demonstration de l'unicite de cet equilibre
IN THIS PAPER, we study the existence of a general equilibrium in an economy in which some of the firms behave competitively, whereas others follow special pricing rules. An even casual observation of economic reality confirms the need for the inclusion of price setting firms in the study of general equilibrium models. And, in fact, this has been emphasized in the economic literature for some time. We consider this a sufficient justification to present a general equilibrium model which allows for both types of behavior-price setting as well as price taking behavior. The model to be presented will account for a wide range of price setting rules. We, however, find it appropriate to point out at the start that not all economically relevant price setting rules are covered. Although our model permits the drawing of useful conclusions for the general equilibrium theory of oligopolistic competition through prices, it is not especially designed for that purpose. In particular, our results are not applicable to the general equilibrium analysis with price making monopolistic firms, a subject on which there exists some literature.2 Our motivation as well as our modelling options and assumptions are directed to two fields where an increased interest in the theoretical foundations recently could be noticed.
[The paper proves sufficient conditions for aggregate demand curves to be decreasing in an economy with identical consumers. The restrictions affect the functional form of Engel curves and the shape of expenditures distribution within the economy. It is shown that most of the empirical literature about Engel curves uses functional forms of the type studied here. Eventually, conditions about expenditures distribution are empirically tested.]