Knowledge that Transforms

This paper establishes a natural and satisfying characterization of the class of collective choice rules which are acyclic and satisfy the Arrow axioms (unrestricted domain, independence of irrelevant alternatives, and the weak Pareto principle). We show that, when the number of alternatives is larger than the number of individuals, there must exist an individual who can at least some critical number of pairwise decisions. This critical number of veto pairs depends on the number of alternatives and individuals, and, as the number of alternatives increases without limit, the fraction of all pairs which some individual can veto approaches unity. We also present a global veto theorem and an axiomatic characterization of the Pareto extension rule which utilizes acyclicity rather than quasi-transitivity. ARROW [1] SHOWED that the only collective choice rules that yield weak order social preference relations and satisfy unrestricted domain, independence of irrelevant alternatives, and the weak Pareto principle are dictatorial. Gibbard [9] demonstrated that by relaxing the rationality requirement from transitivity to quasi-transitivity (i.e., transitivity of the strict preference relation) we can evade the letter though not the spirit of the Arrow dictatorship result: oligarchy, a weaker form of dictatorship, still obtains when the other three axioms are imposed. In this paper we prove a theorem parallel to those of Arrow and Gibbard for the weaker rationality requirement of acyclicity (i.e., the absence of cycles of strict preference). Since acyclicity is a necessary and sufficient condition for the existence of a nonempty set of maximal elements in every finite feasible set, there are powerful reasons for imposing it. Moreover, as we argue in Blair and Pollak [2], it is difficult to justify any stronger rationality property such as quasi-transitivity without at the same time justifying some even stronger rationality condition which implies dictatorship. Our principal result shows that, when the number of alternatives is larger than the number of individuals, there must exist an individual who can at least some critical number of pairwise decisions. (We say that individual i has a veto over the ordered pair (y, x) if he is weakly decisive for x against y-that is, if his strict preference for x over y implies weak social preference for x over y, regardless of the preferences of other individuals.) This critical number of veto pairs depends on the number of alternatives and the number of individuals. As the number of alternatives increases without limit, the fraction of all pairs that some individual can veto approaches unity. There may be more than one individual who can veto at least the critical number of pairs; indeed, it is possible for every individual to have a veto over every ordered pair of alternatives.

We devise and apply a new method for estimating demand for local public goods from survey data. Individuals' responses to questions about whether they wanted more, less, or the same amount of various local public goods are combined with observations of their incomes, tax rates, and the amounts of actual spending in their home communities. Parameter estimates turn out to be quite similar to those found with studies like Bergstrom and Goodman's study based on total expenditures across communities.

[This paper proposes a simple theory to explain bargaining impasses, which is based on Schelling's view of the bargaining process as a struggle between bargainers to commit themselves to favorable bargaining positions. Because bargaining impasses are generally Pareto-inefficient, anything involving a positive probability of impasse is Pareto-inefficient as well. It is demonstrated that in spite of this avoidable inefficiency, when successful commitment is uncertain and irreversible it can still be rational for individuals to attempt commitment and thereby risk an impasse; in a leading special case, the model reduces to a Prisoner's Dilemma game, in which only strategic-dominance arguments are needed to establish this conclusion. Further, making commitment more difficult, or changing the costs of disagreement in a way that makes available a wider range of settlements that are better for both bargainers than disagreement, need not always lower the probability of impasse, in spite of the conventional wisdom to the contrary.]

THE MAIN PURPOSE of this paper is to provide an axiomatic approach to marginal cost (MC) pricing and to point out its similarity with Aumann-Shapley (A-S) pricing. The latter is a cost-sharing price mechanism discussed in [3 and 6] that is derived from a set of five natural axioms. In this paper we consider models in which there is one producer with a given technology who faces fixed input prices and produces a finite number of consumption goods. Thus, we can uniquely derive the cost function that describes the minimal cost of producing a given vector of consumption goods. By a price mechanism P(., ) we mean a rule or a function that associates with each cost function F and vector a of quantities, a vector of prices:

[A class of decompositions is derived for the variance-covariance matrix Ω of a generalized error components model, introduced in [18 and 19]. The spectral decomposition of Ω is a member of this class. For estimation purposes certain other members of the class are preferred, especially those that allow for simplifying transformations of the model not depending on unknown parameters. The transformations suggest simple and asymptotically efficient estimators of both the parameters in Ω and the parameters in the systematic part of the model.]

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Examples are given which show that:(i) normality is not Necessary for the consistency of the quasi maximum likelihood estimator in the nonlinear simultaneous equations model (nonlinear FIML) even when there are major departures from linearity; and (ii) the lemma which is used extensively by Amemiya [2] in the theoretical development of the properties of nonlinear FIML under the assumption of normality is, as presently stated, incorrect.

An update of a classic book in the field, Modern Portfolio Theory examines the characteristics and analysis of individual securities as well as the theory and practice of optimally combining securities into portfolios. It stresses the economic intuition behind the subject matter while presenting advanced concepts of investment analysis and portfolio management. Readers will also discover the strengths and weaknesses of modern portfolio theory as well as the latest breakthroughs.