The Effect of Approval Balloting on Strategic Voting under Alternative Decision Rules

Voting systems combine balloting methods with decision rules or procedures. Most analyses of approval voting (a balloting method) assume it will be combined with plurality rule but advocates often urge its use with more complex procedures. Because much of the case for approval balloting hinges on its encouragement of sincere voting, we ask whether it retains this advantage when combined with multistage procedures. After distinguishing five forms of sincere and insincere approval voting, we find that certain elements of multistage procedures promote departures from purely sincere strategies, including, in some instances, strictly insincere voting. However, most strategic approval voting involves truncating the approved list, including bullet-voting, which is especially likely under certain threshold rules. Coalitions also increase members' incentive to truncate. We conclude that approval balloting with plurality rule remains preferable to conventional single-vote plurality, but we urge caution and further research regarding combining approval balloting with multistage rules.