The Impact of Dependence among Voters’ Preferences with Partial Indifference

International audienceStandard Weighted Scoring Rules do not directly accommodate the possibility that some voters might have dichotomous preferences in three-candidate elections. The direct solution to this issue would be to require voters to arbitrarily break their indifference ties on candidates and report complete rankings. This option was previously found to be a poor alternative when voters have completely independent references. The introduction of a smalldegree of dependence among voters’ preferences has typically been found to make a significant reduction of the impact of such negative outcomes in earlier studies. However, we find that the forced ranking option continues to be a poor choice when dependence is introduced among voters’ preferences. This conclusion is reinforced by the fact that other voting options like Approval Voting and Extended Scoring Rules have been found to produce much better results. These observations are made as a result of using a significant advancement in techniques that obtain probability representations for such outcomes