Properties of Majoritarian Compromise, Efficient Compromise, and Related Compromise Rules

Vincent Merlin (CREM, Univ. Caen Normandie)

17-01-09_Merlin Vincent

Choix social / Social Choice

En collaboration avec Ipek Ozkal SanverIpek Ozkal Sanver (Istanbul Bilgi University) et M. Remzi Sanver (CNRS, LAMSADE)

Abstract :
There is a recently growing interest in social choice rules using the trade-off between the quality and quantity of support behind alternatives. Without being exhaustive we can quote Sertel’s Majoritarian Compromise (MC), Brams and Kilgour’s q-Approval Fallback Bargaining (q-AFB), Ozkal-Sanver and Sanver’s Efficient Compromise (EC), Nurmi’s Condorcet Practical Method (CPM) and Bassett and Persky’s Median Voting Rule (MVR). Our point is that all these concepts which seem a priori different share a common feature which enable us to gather them in the same class, the class of compromise rules. They are all based upon elementary scoring rules which have been described extensively by Saari in a series of masterpiece papers on the properties of scoring rules. As a result, one can exploit these results to analyze the compromise rules with relative ease, which is the main point of our paper.