Binary effectivity rules

A social choice rule (SCR) is a collection of social choice correspondences, one for each agenda. An effectivity rule is a collection of effectivity functions, one for each agenda. We prove that every monotonic and superadditive effectivity rule is the effectivity rule of some SCR. A SCR is binary if it is rationalized by an acyclic binary relation. The foregoing result motivates our definition of a binary effectivity rule as the effectivity rule of some binary SCR. A binary SCR is regular if it satisfies unanimity, monotonicity, and independence of infeasible alternatives. A binary effectivity rule is regular if it is the effectivity rule of some regular binary SCR. We characterize completely the family of regular binary effectivity rules. Quite surprisingly, intrinsically defined von Neumann–Morgenstern solutions play an important role in this characterization.     

Revealed smooth nontransitive preferences

In the present paper, we are concerned with the behavioural consequences of consumers having nontransitive preference relations. Data sets consist of finitely many observations of price vectors and consumption bundles. A preference relation rationalizes a data set provided that for every observed consumption bundle, all strictly preferred bundles are more expensive than the observed bundle. Our main result is that data sets can be rationalized by a smooth nontransitive preference relation if and only if prices can normalized such that the law of demand is satisfied. Market data sets consist of finitely many observations of price vectors, lists of individual incomes and aggregate demands. We apply our main result to characterize market data sets consistent with equilibrium behaviour of pure-exchange economies with smooth nontransitive consumers.     

Efficiency in one-sector,discrete-time,infinite-horizon models

In recent years, a considerable number of papers have been devoted to the problem of characterizing efficient programs in infinite-horizon models. In the present paper on one-sector models, it is shown that (1) the study of production or consumption efficiency can be reduced to the study of a single model, and (2) certain measures of curvature are crucial for the efficiency of programs. Criteria for efficiency of programs using these curvature measures are given and it is indicated how the existing results in the field can be obtained using the present criteria.     

Stochastic stable population theory with continuous time. I

Abstract

This paper contains a systematic presentation of time-continuous stable population theory in modern probabilistic dress. The life-time births of an individual are represented by an inhomogeneous Poisson process stopped at death, and an aggregate of such processes on the individual level constitutes the population process. Forward and backward renewal relations are established for the first moments of the main functionals of the process and for their densities. Their asymptotic convergence to a stable form is studied, and the stable age distribution is given some attention. It is a distinguishing feature of the present paper that rigorous proofs are given for results usually set up by intuitive reasoning only.     

Stochastic Dominance and Conditional Expectation—An Insurance Theoretical Approach

We show that the relation of second order stochastic dominance, which has found widespread use in models of economic behavior under uncertainty, may be described in terms of conditional expectation. If a distribution G second order stochastically dominates another distribution F, then there are random variables g and f with distributions G and F, respectively, such that g can be obtained from f by iterated conditional expectation. In terms of insurance, this shows that the less risky distribution can be obtained by a sequence of insurance contracts each one insuring against the residual risk left over from the previous contracts.     

On the Functional Form of an Efficiency Index

An input efficiency index gives a numeric assessment of the degree to which a given input combination falls short of being efficient in producing a fixed amount of output. This paper presents a system of axioms which characterise a certain family of efficiency indices containing the well-known Farrell and Färe-Lovell indices. The family of indices satisfying the axioms can be obtained by minimizing a suitable function, called a performance evaluation, and different choices of performance evaluation will result in different indices.     

Roles of Statistics in the Life Sciences

Quantitative methodologies have always been central in the life sciences, and some of these belong to the general area of statistics. Other methods of data analysis have their part to play, and it is of ongoing importance for the field of statistics to adapt to these developments.
Besides the role of statistical methods in generating new knowledge, there are also regulatory uses of statistics, particularly in drug registration and in environmental standard setting. These dual roles of statistical methods should not be confused.
Statistical data from official sources and elsewhere play important roles in the life sciences, and often necessitate very careful adherence to confidentiality.
The historical role of the ISI towards life sciences has been modulated by the existence of other international organizations in the area.