Bounded Approval Ballots: Balancing Expressiveness and Simplicity for Multiwinner Elections

Approval ballots have been celebrated for many voting scenarios [16], in particular because of the low cognitive burden they put on the voters. This however, comes at the cost of expressiveness that can be problematic when voters have sophisticated preferences. We consider voters who, in addition to usual approval, may wish to express incompatibilities, dependencies, and/or substitution effects between the alternatives. We introduce, and evaluate a new type of ballot---bounded approval ballots---which captures these effects while being almost as easy as regular approval ballots to cast.