The goal of this paper is to illustrate the significance of information acquisition in mechanism design. We provide a stark example of a mechanism design problem in a collective choice environment with information acquisition. We concentrate on committees that are comprised of agents sharing a...

The goal of this paper is to introduce communication in a collective choice environment with information acquisition. We concentrate on decision panels that are comprised of agents sharing a common goal and having a joint task. Members of the panel decide whether to acquire costly information or...

Arrow's original proof of his impossibility theorem proceeded in two steps: showing the existence of a decisive voter, and then showing that a decisive voter is a dictator. Barbera replaced the decisive voter with the weaker notion of a pivotal voter, thereby shortening the first step, but...

We use a simple graphical approach to represent Social Welfare Functions that satisfy Independence of Irrelevant Alternatives and Anonymity. This approach allows us to provide simple and illustrative proofs of May's Theorem, of variants of classic impossibility results, and of a recent result on...

This introduces the symposium on judgment aggregation. The theory of judgment ag­gregation asks how several individuals' judgments on some logically connected propo­sitions can be aggregated into consistent collective judgments. The aim of this intro­duction is to show how ideas from the...

The veil of ignorance has been used often as a tool for recommending what justice requires with respect to the distribution of wealth. We complete Harsanyi’s model of the veil of ignorance by appending information permitting interpersonal comparability of welfare. We show that the...

We provide an axiomatization of generalized utilitarian social welfare functions in the context of Harsanyi's impartial observer theorem. To do this, we reformulate Harsanyi's problem such that lotteries over identity (accidents of birth) and lotteries over outcomes (life chances) are...

The ethic of 'priority' is a compromise between the extremely compensatory ethic of 'welfare equality' and the needs-blind ethic of ‘income equality’. We propose an axiom of priority, and characterize resource allocation rules that are impartial, prioritarian, and solidaristic. They comprise...

This paper studies a class of multi-self decision-making models proposed in economics, psychology, and marketing. In this class, choices arise from the set-dependent aggregation of a collection of utility functions, where the aggregation procedure satisfies some simple properties. We propose a...

A two-house legislature can often be modelled as a proper simple game whose outcome depends on whether a coalition wins, blocks or loses in two smaller proper simple games. It is shown that there are exactly five ways to combine the smaller games into a larger one. This paper focuses on one of...