Compensation and responsibility

This a chapter for the Handbook of Social Choice and Welfare. It deals with the theory of fairness applied to situations when individuals are partly responsible for their characteristics.fairness, responsibility, equal opportunity, compensation, handicap, talent, effort

On the informational efficiency of simple scoring rules

efficient information aggregation, scoring rules, Poisson games, approval voting

50 % de femmes élues aux communales : faut-il s'y attendre ? Faut-il l'espérer ?

Ce numéro de Regards économiques est consacré à une étude de la parité entre hommes et femmes aux élections en Belgique. La parité obligatoire au niveau des candidats aura sans doute pour effet d'augmenter le pourcentage de conseillères communales, mais ce pourcentage restera sans doute encore longtemps sous les 50 %. Nous donnons quelques éléments d'analyse économique permettant de comprendre les effets de la loi belge sur la parité.

Sharing the Cost of a Public Good: an Incentive-Constrained Axiomatic Approach

We study the problem of provision and cost-sharing of a public good in large economies where exclusion, complete or partial, is possible. We search for incentive-constrained efficient allocation rules that display fairness properties. Population monotonicity says that an increase in population should not be detrimental to anyone. Demand monotonicity states that an increase in the demand for the public good (in the sense of a first-order stochastic dominance shift in the distribution of preferences) should not be detrimental to any agent whose preferences remain unchanged. Under suitable domain restrictions, there exists a unique incentive-constrained efficient and demand-monotonic allocation rule: the so-called serial rule. In the binary public good case, the serial rule is also the only incentive-constrained efficient and population-monotonic rule

Fair Production and Allocation of an Excludable Nonrival Good

We study fairness in economies with one private good and one partially excludable nonrival good. A social ordering function determines for each profile of preferences an ordering of all conceivable allocations. We propose the following Free Lunch Aversion condition: if the private good contributions of two agents consuming the same quantity of the nonrival good have opposite signs, reducing that gap improves social welfare. This condition, combined with the more standard requirements of Unanimous Indifference and Responsiveness, delivers a form of welfare egalitarianism in which an agent's welfare at an allocation is measured by the quantity of the nonrival good that, consumed at no cost, would leave her indifferent to the bundle she is assigned.Dans le contexte d'une économie à un bien privé et un bien non rival, nous montrons que trois principes normatifs simples forcent à classer les allocations en appliquant le critère maximin aux vecteurs de bien-être mesuré en termes du bien non rival

Efficient Strategy-Proof Allocation Functions in Linear Production Economies

In a linear production model, we characterize the class of efficient and strategy-proof allocation functions, and the class of efficient and coalition strategy-proof allocation functions. In the former class, requiring equal treatment of equals allows us to identify a unique allocation function. This function is also the unique member of the latter class which satisfies uniform treatment of uniforms.Dans le cadre d'une économie de production à technologie linéaire, nous caractérisons les règles d'allocation efficaces et non manipulables, tant au sens individuel que coalitionnel. Différentes propriétés de symétries nous permettent ensuite d'isoler une règle unique

Compensation and responsibility

This a chapter for the Handbook of Social Choice and Welfare. It deals with the theory of fairness applied to situations when individuals are partly responsible for their characteristics

Virtual Nash implementation with admissible support

A social choice correspondence (SCC) is virtually implementable if it is ε-close (in the probability simplex) to some (exactly) implementable correspondence. Abreu and Sen (1991) proved that, without restriction on the set of alternatives receiving strictly positive probability at equilibrium, every SCC is virtually implementable in Nash Equilibrium. We study virtual implementation when the supports of equilibrium lotteries are restricted. We provide a necessary and sufficient condition, imposing joint restrictions on SCCs and admissible supports. Then, we discuss how to construct supports. Finally, we study virtual implementation when the support is restricted to the efficient or individually rational alternatives.

On a three-alternative Condorcet jury theorem

We investigate whether the simple plurality rule aggregates information efficiently in a large election with three alternatives. The environment is the same as in the Condorcet Jury Theorem (Condorcet (1785)). Voters have common preferences that depend on the unknown state of nature, and they receive imprecise private signals about the state of nature prior tovoting. With two alternatives and strategic voters, the simple plurality rule aggregates information efficiently in elections with two alternatives (e.g., Myerson (1998)). We show that there always exists an efficient equilibrium under the simple plurality rule when there are three alternatives as well. We characterize the set of inefficient equilibria with two alternatives and the condition under which they exist. There is only one type of inefficient equilibrium with two alternatives. In this equilibrium, voters vote unresponsively because they all vote for the same alternative. Under the same condition, the same type of equilibrium exists with three alternatives. However, we show that the number and types of coordination failures increase with three alternatives, and that this leads to the existence of other types of inefficient equilibria as well, including those in which voters vote informatively

Focus 6 - février 2013

Il existe une sorte de consensus implicite entre économistes, politiciens et membres de la société civile pour trouver légitime que l'Etat intervienne dans la répartition du bien-être au sein de la société, et tout particulièrement pour en diminuer la pauvreté. Les opinions divergent fortement, par contre, lorsqu'il s'agit de définir la manière d'intervenir. Un des principaux dilemmes concerne le choix à faire entre contrôler les prix, en les fixant temporairement ou en modifiant les taux de TVA, ou contrôler les revenus, en modifiant le système de transferts. Par exemple, dans le cas d'une augmentation des prix de l'énergie, l'Etat doit-il subsidier le prix de l'énergie auquel font face les plus pauvres ou doit-il compenser l'augmentation des prix de l'énergie par un ajustement des transferts (pensions, revenus minimaux, allocations de chômage)