Multiwinner approval voting: an apportionment approach

Steven Brams, D. Marc Kilgour, Richard F. Potthoff

    Research output: Contribution to journalArticle

    Abstract

    To ameliorate ideological or partisan cleavages in councils and legislatures, we propose modifications of approval voting in order to elect multiple winners, who may be either individuals or candidates of a political party. We focus on two divisor methods of apportionment, first proposed by Jefferson and Webster, that fall within a continuum of apportionment methods. Our applications of them depreciate the approval votes of voters who have had one or more approved candidates elected and give approximately proportional representation to political parties. We compare a simple sequential rule for allocating approval votes with a computationally more complex simultaneous (nonsequential) rule that, nonetheless, is feasible for many elections. We find that our Webster apportionments tend to be more representative than ours based on Jefferson—by giving more voters at least one representative of whom they approve. But our Jefferson apportionments, with equally spaced vote thresholds that duplicate those of cumulative voting in two-party elections, are more even-handed. By enabling voters to express support for more than one candidate or party, these apportionment methods will tend to encourage coalitions across party or factional lines, thereby diminishing gridlock and promoting consensus in voting bodies.

    Original languageEnglish (US)
    JournalPublic Choice
    DOIs
    StateAccepted/In press - Jan 1 2018

    Fingerprint

    voting
    voter
    candidacy
    election
    coalition party
    proportional representation
    Approval voting
    Voters
    Vote
    Voting
    Elections
    Political parties
    Proportional representation
    Legislatures

    Keywords

    • Apportionment
    • Approval voting
    • Cumulative voting
    • Divisor methods
    • Multiple winners

    ASJC Scopus subject areas

    • Sociology and Political Science
    • Economics and Econometrics

    Cite this

    Multiwinner approval voting : an apportionment approach. / Brams, Steven; Kilgour, D. Marc; Potthoff, Richard F.

    In: Public Choice, 01.01.2018.

    Research output: Contribution to journalArticle

    Brams, Steven ; Kilgour, D. Marc ; Potthoff, Richard F. / Multiwinner approval voting : an apportionment approach. In: Public Choice. 2018.
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