Plurality criterion

Statement of Criterion

If the number of ballots ranking A as the first preference is greater than the number of ballots on which another candidate B is given any preference, then A's probability of election must be no less than B's.

Complying Methods

First-Preference Plurality, Approval voting, IRV, and many Condorcet methods (using winning votes as defeat strength) satisfy the Plurality criterion. Condorcet methods using margins as the measure of defeat strength fail it, as does Raynaud (using either winning votes or margins as the measure of defeat strength), and also Minmax(pairwise opposition).

Commentary

It is difficult to imagine that a method could have a good reason to elect B over A when the voters giving B any ranking at all are outnumbered by the voters who ranked A as being the best candidate. The Plurality criterion is about avoiding such unintuitive results.