Social Choice Theory

The Intellectual Influence of Economic Journals: Quality versus Quantity

by László Kóczy

Co-authored with Alex Nichifor; accepted at Economic Theory

The evaluation of scientific output has a key role in the allocation of research funds and academic positions.... more The evaluation of scientific output has a key role in the allocation of research funds and academic positions. Decisions are often based on quality indicators for academic journals and over the years a handful of scoring methods have been proposed for this purpose. Discussing the most prominent methods (de facto standards) we show that they do not distinguish quality from quantity at article level. The systematic bias we find is analytically tractable and implies that the methods are manipulable. We introduce modified methods that correct for this bias, and use them to provide rankings of economic journals. Our methodology is transparent; our results are replicable.

La question du «choix» dans la décision de se marier ou non au Québec

by Hélène Belleau

Belleau, H. et P. Cornut-St-Pierre (2011), Lien social et politiques, no. 66, p.65-89.

R É S U M É | A B S T R AC T

In the debate over whether or not legislation is needed to regulate... more R É S U M É | A B S T R AC T

In the debate over whether or not legislation is needed to regulate common-law marriage, Quebec lawmakers have so far maintained that it is important to preserve the free choice of individuals who wish to live together outside the institution of
marriage. This position rests on four premises regarding the “choice” that couples make when they decide to marry or not – premises that are not based on any empirical findings. Taking into consideration the views of couples on married life
and applying concepts from the sociology of law such as internormativity, legal consciousness and efficacy of legislation, this paper shows that the decision to marry or not is in fact founded on reasons and norms that often have no legal basis,
and that the reference to “common-law” status in social and tax legislation perpetuates the widespread but mistaken belief that couples in common-law relationships, after living together for a few years or having a child together, enjoy a status or protection equivalent to that of married couples.

Dans le débat sur la pertinence d’un encadrement légal de l’union libre, le législateur québécois a jusqu’à maintenant soutenu l’importance de préserver le libre choix des individus qui souhaitent vivre en dehors des cadres du mariage. Un tel argument repose sur quatre postulats quant au « choix » que font les couples lorsqu’ils prennent la décision de se marier ou non, postulats qui ne sont étayés par aucune étude empirique. En tenant compte du point de vue des couples sur la vie conjugale et à l’aide de notions de sociologie du droit telles l’internormativité, la conscience du droit et l’effectivité des lois, l’article montre que la décision des couples de se marier ou non repose en fait sur des motifs et des normes qui n’ont souvent rien de juridique, et que l’imposition d’un statut de « conjoint de fait » par les lois sociales et fiscales entretient la perception répandue mais erronée selon laquelle les conjoints de fait jouiraient, après quelques années de vie commune ou la naissance d’un enfant, d’un statut et d’une protection équivalents à ceux des couples mariés.

Come valuatre la qualità di un servizio pubblico differenziato territorialmente

by marcucci edoardo

Residential location preferences and relative power in three-member households- a choice experiment

by marcucci edoardo

An analytic logic of aggregation

by Jeremy Seligman

GIRARD, P. and SELIGMAN, J. ‘An analytic logic of aggregation’ In R. Ramanujam and S. Sarukkai (eds.) Proc. of the Third Indian Conference on Logic and Applications, Springer LNAI 5378, pp. 148–163, 2009.

We present a modular approach to the logic of aggregated group preferences based on hybrid modal logic. The modularity... more We present a modular approach to the logic of aggregated group preferences based on hybrid modal logic. The modularity of the system is twofold: 1) lifting preference relations between states to complex relations between propositions and 2) lifting individual preferences to group preferences. The preferences may be doxastic or proairetic, generating a logic of aggregated belief or aggregated desire, respectively, using a specific aggregation policy known as ‘lexicographic re-ordering’. Each agent and each group of agents has an associated modal operator representing their preferences between states. The addition of the existential modality and nominals allows us to produce, first, a Hilbert-style axiomatization of the logic and then a more thorough analysis of inference using a Gentzen-style sequent calculus, in which the role of each operator is revealed.

FinalDissertation2010

by Kevin Merges

Risk Aversion, Over-Confidence and Private Information as Determinants of Majority Thresholds

by Francesco Passarelli

Co-authored with G. Attanasi, L. Corazzini, N. Georgantzis

We present and experimentally test a theoretical model of majority threshold determination as a function of voters'... more We present and experimentally test a theoretical model of majority threshold determination as a function of voters' risk preferences. The experimental results confirm the theoretical prediction of a positive correlation between a voter's risk aversion and the corresponding preferred majority threshold. Furthermore, the experimental results show that a voter's optimal majority threshold negatively relates to the voter's confidence about how others will vote. Moreover, in a treatment in which individuals receive a private signal about others' voting behavior, the private signal tends to replace confidence.

The value of choice: the development of a new measurement tool

by Jane Ogden

Why does virtue lie in the middle ground? Rationing problems with legitimate principles

by José-Manuel Jiménez-Gómez

A rationing problem appears each time that the available quantity of a particular good is insufficient to satisfy the... more A rationing problem appears each time that the available quantity of a particular good is insufficient to satisfy the "objective rights" that a group of agents has on it. The most characteristic example is the bankruptcy of a company, hence the designation of such problems in the economic literature as “Bankruptcy Problems”. This type of problem is formally described by a vector such that , where E is the available quantity of the good to be distributed among agents in the set , and each coordinate is interpreted as the demand for good by the i-th agent, meaning the condition reflects the incompatibility of all rights. In this model, a solution called Bankruptcy Rule involves applying a procedure for each bankruptcy problem that ensures a distribution of the good that takes the differences among agents' claims into account. To summarize, on the one hand, therefore, by ensuring a minimal amount of awards to each claimant, we provide new basis from Axiomatic and Strategic viewpoints, for classical and well-known bankruptcy rules: the Constrained Equal Awards, the Constrained Equal Losses, Piniles' and its dual, and the Constrained Egalitarian and its dual. We also explain how the combination of social agreements on principles and recursive procedure may become implausible. On the other hand, by using these approaches and by requiring both a lower and an upper bound on awards, we can reasonably sustain the proposal of "intermediate" agreements for bankruptcy problems, from among all the solutions that are considered \textit{Admissible} for a given society, i.e., the ones satisfying the set of Legitimate Principles established by and for the society (we retrieve the average between two prominent allocations). Moreover, by using the Cooperative Game Approach, we also find solid grounds for selecting the average of the two focal viewpoints from among all the intermediate compromises, supporting very simple, current and commonly observed collective decisions. Considering all the above, we think that the current dissertation sheds light onto the question posed in its title: Why does virtue lie in the middle ground?

A New Approach for Bounding Awards in Bankruptcy Problems

by José-Manuel Jiménez-Gómez

M.Carmen Marco Gil

The solution for the ‘Contested Garment Problem’ proposed in the Babylonic
Talmud, suggests that each agent... more The solution for the ‘Contested Garment Problem’ proposed in the Babylonic
Talmud, suggests that each agent should receive at least some part of the available
amount when facing situations where demand overcomes supply of some endowment.
This idea has underlied the theoretical analysis of bankruptcy problems
from its beginning (O’Neill, 1982) to present day (Dominguez and Thomson, 2006).
In this context, we propose a new method to define lower bounds on awards. Starting
from the fact that a society establishes its own set of ‘Commonly Accepted Equity
Principles’, our proposal ensures each agent the smallest amount she gets according
to all the admissible rules for such a society. We particularize the previous idea for
different sets of equity principles. Moreover, we analyze the recursive application of
this new bound, since it will not exhaust the endowment, in general.

A way to play bankruptcy problems.

by José-Manuel Jiménez-Gómez

The commitment among agents has always been a difficult task, especially when they have to decide how to distribute... more The commitment among agents has always been a difficult task, especially when they have to decide how to distribute the available amount of a scarce resource among all. On the one hand, there are a multiplicity of possible ways for assigning the available amount; and, on the other hand, each agent is going to propose that distribution which provides her the highest possible award. In this paper, with the purpose of making this agreement easier, firstly we use two different sets of basic properties, called Commonly Accepted Equity
Principles, to delimit what agents can propose as reasonable allocations. Secondly, we extend the results obtained by Chun (1989) and Herrero (2003), obtaining new characterizations of old and well known bankruptcy rules. Finally, using the fact that bankruptcy problems can be analyzed from awards and losses, we define a mechanism which provides a new justification of the
convex combinations of bankruptcy rules.

Some game-theoretic grounds for meeting people half-way

by José-Manuel Jiménez-Gómez

M.Carmen Marco Gil
Pedro Gadea

It is well known that, in distributions problems, ‘Fairness’rarely leads to a single viewpoint (see Young (1994) and... more It is well known that, in distributions problems, ‘Fairness’rarely leads to a single viewpoint (see Young (1994) and Moulin (1988) among many others). This paper provides, in this context, interesting basis in defense of intermediate agreements when two prominent proposals, representing different sets of ‘Equity principles’, highlight a discrepancy in sharing resources. Specifically, we formalize such a conf‡icting situation by associating it with a ’natural’cooperative game, called the Bi-
focal Distribution game, to show that both the Nucleolus, introduced by Schmeidler (1969), and the Shapley value, proposed by Shapley (1953), agree on recommending the ’average of the two focal solutions’. Finally, applying our analysis to bankruptcy problems, which have been analyzed extensively by Thomson (2003) and Moulin (2002), provides new ’reasonable’solutions.

Mediation in bankruptcy problems.

by José-Manuel Jiménez-Gómez

Josep E. Peris

Mediation is a recently dispute resolution process where agents reach a mutually
acceptable agreement among... more Mediation is a recently dispute resolution process where agents reach a mutually
acceptable agreement among prominent proposals. This paper provides
a natural way of coming to this agreement in bankruptcy problems. The central
fact is that such problems can be faced from two different points of view:
awards and losses. Given this views, we assume that agents decide a group
of principles on which the distribution of the available resources should be
based. Next we define a double recursive process by the application of both a
lower and an upper bound on awards. Finally, by considering three possible
sets of principles we retrieve the average of old and well known bankruptcy
rules, the Constrained Equal Awards and the Constrained Equal Losses rules,
Piniles’ rule and its dual rule, and the Constrained Egalitarian rule and its
dual rule.

Do we agree? Measuring the cohesiveness of preferences

by Marc Vorsatz

joint with Jorge Alcalde Unzu, Unpublished Working Paper, 2010.

In this paper, we suggest new ways of how to measure the similarity of preferences in a group of individuals. For... more In this paper, we suggest new ways of how to measure the similarity of preferences in a group of individuals. For simplicity, we refer to this as the cohesiveness (of preferences). We propose axioms a cohesiveness measure should satisfy and show that these properties fully characterize a family of measures. According to it, the similarities between each pair of objects in a preference profile -calculated as the proportion margin by which one objects wins against the other in a pairwise comparison- are aggregated by a weighted mean. The weight of each pair of objects depends on their importance at the social level

The Measurement of Consensus: An Axiomatic Study

by Marc Vorsatz

joint with Jorge Alcalde Unzu, Unpublished Working Paper, 2008.

The cohesion of a society depends to large extend on the degree to which its members coincide in their preferences... more The cohesion of a society depends to large extend on the degree to which its members coincide in their preferences (the consensus). This paper proposes axioms a consensus measure should satisfy from a normative point of view and characterizes first a class of linear and additive measures which fulfills an ordinal property similar to the concepts of first order stochastic dominance in the literature on individual decision making under risk and Lorenz curve domination in the literature on income inequality measurement. With the help of some additional properties, it is then possible to isolate from this broad class of measures a subfamily that only depends on a single parameter. Finally, we show that the consensus measures associated with the focal parameters of this subfamily have an intuitive explanation and we characterize them separately.

Size approval voting

by Marc Vorsatz

joint with Jorge Alcalde Unzu, Working Paper, published in Journal of Economic Theory 144: 1187-1210, 2009.

We propose a new class of voting procedures, called Size Approval Voting, according to which, the effective weight of... more We propose a new class of voting procedures, called Size Approval Voting, according to which, the effective weight of a vote from a given individual depends on how many other candidates that individual votes for. In particular, weights are assumed to be non-negative and weakly decreasing in the number of approved candidates. Then, for a given profile of individual votes, all candidates with the maximal sum of weighted votes are elected. We show in our axiomatic analysis that the family of all Size Approval Voting procedures is characterized by a set of natural properties.

Scoring rules on dichotomous preferences

by Marc Vorsatz

Working Paper, published in Social Choice and Welfare 31: 151-162.

In this paper, we study individual incentives to report preferences truthfully for the special case when individuals... more In this paper, we study individual incentives to report preferences truthfully for the special case when individuals have dichotomous preferences on the set of alternatives and preferences are aggregated in form of scoring rules. In particular, we show that (a) the Borda Count coincides with Approval Voting, (b) the Borda Count is the only strategy-proof scoring rule, and (c) if the size of the electorate is greater than three, then the dichotomous preference domain is the unique maximal rich domain under which the Borda Count is strategy-proof.

Weighted approval voting

by Marc Vorsatz

joint with Jordi Massó, Working Paper, published in Economc Theory 36: 129-146, 2008.

To allow society to treat unequal alternatives distinctly we propose a natural extension of Approval Voting by... more To allow society to treat unequal alternatives distinctly we propose a natural extension of Approval Voting by relaxing the assumption of neutrality. According to this extension, every alternative receives ex-ante a strictly positive and finite weight. These weights may differ across alternatives. Given the voting decisions of every individual (individuals are allowed to vote for, or approve of, as many alternatives as they wish to), society elects the alternative for which the product of total number of votes times exogenous weight is maximal. If the product is maximal for more than one alternative, a pre-specified tie-breaking rule is applied. Our main result is an axiomatic characterization of this family of voting procedures.

Approval voting on dichotomous preferences

by Marc Vorsatz

Working Paper, published in Social Choice and Welfare 28: 127-141, 2007.

The aim of this paper is to find normative foundations of Approval Voting when individuals have dichotomous... more The aim of this paper is to find normative foundations of Approval Voting when individuals have dichotomous preferences. We show that a social choice function is anonymous, neutral, strategy-proof and strictly monotone if and only if it is Approval Voting and interpret this result as an extension of May’s theorem (Econometrica 20:680–684, 1952). Then, we show that Approval Voting is the only strictly symmetric, neutral and efficient social choice function. This result is related to a characterization of Baigent and Xu (Math Soc Sci 21:21–29, 1991).

The institutional landscape of interest group politics and school choice

by Janelle Scott