The Impact of Group Coherence on the Condorcet Ranking Efficiency of Voting Rules

Recent developments in voting theory, based on both probabilistic and empirical considerations, have led to the conclusion that Condorcet’s paradox should be a rare event in actual election settings with a small number of candidates, as soon as voters display any significant level of group mutual coherence, i.e. as soon as voters tend, in one way or another, to have similar preferences (see e.g. Gehrlein 2011, and for an empirical point of view, Regenwetter et al. 2006). In the light of this conclusion, the Condorcet criterion, which requires that the pairwise majority rule winner (PMRW) – or Condorcet winner – should be elected when such a candidate exists, appears as being very relevant. It is therefore of particular interest to investigate the propensity of common voting rules to be in agreement with pairwise majority rule (PMR)

when group coherence is taken into consideration

.