Scoring rules, condorcet efficiency and social homogeneity

• Published in: Theory and decision Vol. 49; no. 2; pp. 175 - 196
• Main Authors: LEPELLEY, Dominique, PIERRON, Patrick, VALOGNES, Fabrice
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.09.2000; Springer Nature B.V
• Subjects: Applied sciences; Binomial distribution; Candidates; Consensus; Decision making; Decision theory. Utility theory; Economic choice; Efficiency; Elections; Exact sciences and technology; Inequality; Majority rule; Majority voting system; Mathematical analysis; Operational research and scientific management; Operational research. Management science; Preferences; Probability; Statistical models; Studies; Voter behavior; Voters; Voting behaviour; United States > US; Probabilistic approach; Voting; Preference; Social sciences; Decision theory; Homogeneity; Conditional probability
• ISSN: 0040-5833; 1573-7187
• DOI: 10.1023/A:1005257316414

In a three-candidate election, a scoring rule [lambda], [lambda][is an element of][0,1], assigns 1,[lambda] and 0 points (respectively) to each first, second and third place in the individual preference rankings. The Condorcet efficiency of a scoring rule is defined as the conditional probability that this rule selects the winner in accordance with Condorcet criteria (three Condorcet criteria are considered in the paper). We are interested in the following question: What rule [lambda] has the greatest Condorcet efficiency? After recalling the known answer to this question, we investigate the impact of social homogeneity on the optimal value of [lambda]. One of the most salient results we obtain is that the optimality of the Borda rule ([lambda]=1/2) holds only if the voters act in an independent way. [PUBLICATION ABSTRACT]