Strategy-proof preference aggregation
Series/Report no.Cahier de recherche #2012-10
An aggregation rule maps each proﬁle of individual strict preference orderings over a set of alternatives into a social ordering over that set. We call such a rule strategyproof if misreporting one’s preference never produces a social ordering that is strictly between the original ordering and one’s own preference. After describing a few examples of manipulable rules, we study in some detail three classes of strategy-proof rules: (i)rules based on a monotonic alteration of the majority relation generated by the preference proﬁle; (ii)rules improving upon a ﬁxed status-quo; and (iii) rules generalizing the Condorcet-Kemeny aggregation method.