I. the origin of species by means of natural selection

The notion of diversity is an issue that is of relevance in several contexts. For example, the biodiversity of a given ecological environment and the diversity of the options available to a decision maker have attracted some attention in recent research. This paper provides an axiomatic approach to the measurement of diversity. We characterize two nested classes of ordinal measures of diversity and an important member of these classes. We prove that the latter special case is equivalent to a diversity ordering proposed by Weitzman.

The Measurement of Diversity

In the Hamadryas baboon, males are substantially larger than females. A troop of baboons is subdivided into a number of ‘one-male groups’, consisting of one adult male and one or more females with their young. The male prevents any of ‘his’ females from moving too far from him. Kummer (1971) performed the following experiment. Two males, A and B, previously unknown to each other, were placed in a large enclosure. Male A was free to move about the enclosure, but male B was shut in a small cage, from which he could observe A but not interfere. A female, unknown to both males, was then placed in the enclosure. Within 20 minutes male A had persuaded the female to accept his ownership. Male B was then released into the open enclosure. Instead of challenging male A , B avoided any contact, accepting A’s ownership.

Evolution and the Theory of Games

This paper proposes a new methodology for multidimensional poverty measurement consisting of an identification method ρk that extends the traditional intersection and union approaches, and a class of poverty measures Mα. Our identification step employs two forms of cutoff: one within each dimension to determine whether a person is deprived in that dimension, and a second across dimensions that identifies the poor by ‘counting’ the dimensions in which a person is deprived. The aggregation step employs the FGT measures, appropriately adjusted to account for multidimensionality. The axioms are presented as joint restrictions on identification and the measures, and the methodology satisfies a range of desirable properties including decomposability. The identification method is particularly well suited for use with ordinal data, as is the first of our measures, the adjusted headcount ratio. We present some dominance results and an interpretation of the adjusted headcount ratio as a measure of unfreedom. Examples from the US and Indonesia illustrate our methodology.

Counting and Multidimensional Poverty Measurement

Anarchy, state, and utopia

This chapter focuses on criteria and methods for ranking subsets of a set of objects. There are many situations in which rankings of individual objects suffice for classification or decision making purposes, but many other situations call for rankings that involve subsets of two or more objects. The chapter identifies contexts in which subset rankings are important and discusses a number of ways in which such rankings might be obtained.

/pdf/ranking-sets-of-objects-1c4r2u1iw9.pdf

Ranking Sets of Objects

Redistribution mechanisms based on individual characteristics

Ranking Opportunity Sets: An Axiomatic Approach

In Arrovian [Arrow (1951, 1963)] social choice theory, the objective is to construct a social welfare function—a mapping which assigns a social preference ordering to each admissible profile of individual preferences—satisfying several a priori appealing conditions. Arrow showed that the only social welfare functions satisfying his axioms are dictatorial in the sense that there exists an individual whose strict preference over any two social alternatives is always replicated in the social ordering, no matter what the preferences of the remaining members of society happen to be. This negative result has initiated a series of contributions which attempt to avoid Arrow’s impossibility theorem by weakening one or more of his original axioms. The results in this literature are, on the whole, rather negative as well.

Walter Bossert

Papers

Ranking Sets of Objects

Redistribution mechanisms based on individual characteristics

Ranking Opportunity Sets: An Axiomatic Approach

Utility in Social Choice

Population Issues in Social Choice Theory, Welfare Economics, and Ethics: Uncertainty and Incommensurabilities