The Chamberlin-Courant Rule and the k-Scoring Rules: Agreement and Condorcet Committee Consistency

Abstract : For committee or multiwinner elections, the Chamberlin-Courant rule (CCR), which combines the Borda rule and the proportional representation, aims to pick the most representative committee (Chamberlin and Courant, 1983). Chamberlin and Courant (1983) have shown that if the size of the committee to be elected is k = 1 among m ≥ 3 candidates, the CCR is equivalent to the Borda rule; Kamwa and Merlin (2014) claimed that if k = m − 1, the CCR is equivalent to the k-Plurality rule. In this paper, we explore what happens for 1 < k < m − 1 by computing the probability of agreement between the CCR and four k-scoring rules: k-Plurality, k-Borda, k-Negative Plurality and Bloc. Our results show that for committees of at least two members, the CCR usually leads to a committee recommended by the k-Plurality rule. Furthermore, we evaluate the probability of the CCR to select the Condorcet committee à la Gehrlein when it exists. The Condorcet committee à la Gehrlein is a fixed size subset of candidates such that every meber defeats every non-member in pairwise comparisons. In this matter, our results indicate that the CCR performs less well than the k-Borda rule and the Bloc rule but better than the k-Plurality and the k-Negative Plurality rules.
Type de document :
Pré-publication, Document de travail
Working paper GATE 2018-12. 2018
Liste complète des métadonnées

Littérature citée [61 références]  Voir  Masquer  Télécharger

https://halshs.archives-ouvertes.fr/halshs-01817943
Contributeur : Nelly Wirth <>
Soumis le : lundi 18 juin 2018 - 15:21:00
Dernière modification le : mercredi 31 octobre 2018 - 12:24:13
Document(s) archivé(s) le : mercredi 19 septembre 2018 - 22:36:33

Fichier

1812.pdf
Fichiers produits par l'(les) auteur(s)

Identifiants

  • HAL Id : halshs-01817943, version 1

Citation

Mostapha Diss, Eric Kamwa, Abdelmonaim Tlidi. The Chamberlin-Courant Rule and the k-Scoring Rules: Agreement and Condorcet Committee Consistency. Working paper GATE 2018-12. 2018. 〈halshs-01817943〉

Partager

Métriques

Consultations de la notice

98

Téléchargements de fichiers

79