Approval Ballots Research Articles

Two field experiments on Approval Voting in Germany

We report on two field experiments on Approval Voting conducted during actual state and federal elections in Germany. Voters provided approval ballots both for named district candidates and for state parties. The data reveal significant discrepancies in the outcomes under the official method and Approval Voting. Further, our analysis suggests that currently used voting methods do a poor job of representing the electorate’s preferences. As a consequence, some recurring features of the political landscape in a given country might be, in part, an artifice of the employed voting method.

Searching for a Compromise in Multiple Referendum

We consider a multiple referendum setting where voters cast approval ballots, in which they either approve or disapprove of each of finitely many dichotomous issues. A program is a set of socially approved issues. Assuming that individual preferences over programs are derived from ballots by means of the Hamming distance criterion, we consider two alternative notions of compromise. The majoritarian compromise is the set of all programs supported by the largest majority of voters at the minimum utility loss. A program is an approval compromise if it is supported by the highest number of voters at a utility loss at most half of the maximal achievable one. We investigate the conditions under which issue-wise majority voting allows for reaching each type of compromise. Finally, we argue that our results hold for many other preferences that are consistent with the observed ballots.

A minimax procedure for electing committees

A new voting procedure for electing committees, called the minimax procedure, is described. Based on approval balloting, it chooses the committee that minimizes the maximum Hamming distance to voters’ ballots, where these ballots are weighted by their proximity to other voters’ ballots. This minimax outcome may be diametrically opposed to the outcome obtained by aggregating approval votes in the usual manner, which minimizes the sum of the Hamming distances and is called the minisum outcome. The manipulability of these procedures, and their applicability when election outcomes are restricted in various ways, are also investigated.

Electing Popes: Approval Balloting and Qualified-Majority Rule

L'A. retrace l'histoire du mode de designation du Pape dans l'Eglise. L'un des enjeux dans cette institution a ete de preserver l'autonomie de l'Eglise catholique face au pouvoir temporel. Les relations entre Pape et empereur romain sont etudiees la pour le souligner. L'A. montre pourquoi l'election papale a longtemps repose sur le principe de l'unanimite : il en montre aussi toutes les limites. Il explique ainsi comment le conclave s'est mis en place, pourquoi on y a instaure la regle de la majorite qualifiee (des deux tiers). Il insiste enfin sur la notion de ballotage favorable et montre aussi toutes les possibilites de manipulation inherentes a ce systeme