BUSCADOR RECOLECTA

The final publication is available at Springer via http://dx.doi.org/10.1007/s00355-012-0716-9, In this paper, we axiomatically study how to measure the similarity of preferences in a group of individuals. For simplicity, we refer to this as the cohesiveness. First, we provide axioms that characterize a family of linear and additive measures whose intersection is a partial ordinal criterion similar to first order stochastic dominance. The introduction of some additional properties isolates a one-parameter subfamily. This parameter evaluates the effect on the cohesiveness if one individual changes his ranking on a single pair of objects, as a function of how many of the remaining individuals in the group rank the first object over the second and vice versa. Finally, we characterize the focal measures of this subfamily separately showing that they coincide with measures constructed using two, at first sight, totally different approaches suggested in the literature., The author Jorge Alcalde-Unzu gratefully acknowledges financial support from the
Spanish Ministry of Education and Science, through the projects ECO2009-11213 and ECO2009-12836.
The author Marc Vorsatz gratefully acknowledges financial support from the Spanish Ministry of Education
and Science (through the project ECO2009-07530) and from the Spanish Ministry of Economy and Competitiveness
(through the project ECO2012-31985).

We study axiomatically situations in which the society agrees to treat voters with different characteristics distinctly. In this setting, we propose a set of intuitive axioms and show that they jointly characterize a new class of voting procedures, called Type-weighted Approval Voting. According to this family, each voter has a strictly positive and finite weight (the weight is necessarily the same for all voters with the same characteristics) and the alternative with the highest number of weighted votes is elected. The implemented voting procedure reduces to Approval Voting in case all voters are identical or the procedure assigns the same weight to all types. Using this idea, we also obtain a new characterization of Approval Voting., The first author’s financial support from the Spanish Ministry of Education and Science, through the project ECO2012–34202, and Fundación Ramón Areces is gratefully acknowledged. The second author’s financial support from the Spanish Ministry of Education and Science, through the project ECO2012–31985, and Fundación Ramón Areces is gratefully acknowledged.