Bloc Voting on Single Peaked Preferences

TL;DR

This paper studies how bloc voting outcomes behave with single-peaked voter preferences, identifying conditions for adjacency in winning coalitions, analyzing pairwise contests, and evaluating multiwinner criteria through simulations.

Contribution

It provides new insights into the structure of winning coalitions in single-peaked preferences and extends Condorcet criteria to multiwinner voting scenarios.

Findings

Winning coalitions are often composed of adjacent candidates in small elections.

Certain multiwinner Condorcet extensions are satisfied under specific conditions.

Simulations reveal the frequency of coalition formations under various voter behaviors.

Abstract

We analyze the winning coalitions that arise under Bloc voting when voters preferences are single-peaked. For small numbers of candidates and numbers of winners, we determine conditions under which candidates in winning coalitions are adjacent. We also analyze the results of pairwise contests between winning and losing candidates and assess when the winning coalitions satisfy several proposed extensions of the Condorcet criterion to multiwinner voting methods. Finally, we use Monte Carlo simulations to investigate how frequently these coalitions arise under different assumptions about voter behavior.