In Response: Ranked-choice voting a mixed bag

I suspect I am among the unspecified mathematicians maligned by the March 13 Local View column, “Ranked-choice voting opponents just trying to sell you a bag of lies.” There is an informal group of us seeking to understand election methods, including costs and benefits, and to share our findings in order to help Duluth make informed choices. There are many methods of electing single winners. Let us consider three: plurality, plurality with runoff and ranked-choice voting, which is also called instant-runoff voting or single-transferable vote. In plurality, each voter votes for one candidate and the candidate with the most votes wins. In plurality with runoff, there is a primary plurality election followed by a runoff between the primary’s top two vote-getters. With ranked-choice voting, voters mark candidates in order of preference, sometimes up to a cut-off. In the 2013 Minneapolis mayoral election, voters ranked up to three candidates.    Ranked-choice voting elections are conducted in rounds. In the first round, each candidate’s votes are his or her total number of first-place rankings among the ballots.  Then, as well as in each subsequent round, the candidate with the fewest votes is eliminated, and for each ballot that contributed a vote to this candidate the vote goes to the ballot’s next ranked candidate not yet eliminated, or, if all the candidates on the ballot have been eliminated, the ballot plays no further role in the election. The final round is a contest between the two remaining candidates, and the one with the most votes wins. See, for example, the 2013 Minneapolis mayoral election rounds table at vote.minneapolismn.gov/results/2013/2013-mayor-tabulation. The pros of plurality include that it is simple to understand and verify, ballots are simple to fill out and votes can be tallied as they are received. Cons of plurality include that similar candidates can split votes, allowing neither to win, even if a majority supports the two candidates’ common platform. This often is referred to as the vote-splitting or spoiler problem. Pros of plurality with runoff include that it is simple, like plurality, and the runoff election produces a majority winner. Voters have an opportunity to become more informed about the two candidates who make it through the primary before voting in the runoff, and people can vote in the runoff even if they did not vote in the primary. Cons of plurality with runoff include the possibility of vote-splitting in the primary election, the potential for low voter participation in the primary, and the need for two elections. Ranked-choice voting avoids the spoiler problem in certain situations, as among its pros. It also allows voters to express preferences for multiple candidates. But its cons include its use of a complicated algorithm, its lack of transparency, its requirement for voter education and specialized software, and its need for all votes to be in before election tabulations can begin. In addition, disputed ballots, late ballots or vote integrity problems require restarting the process. The frequency of contested ranked-choice voting elections, including via recounts and/or lawsuits, may be higher than for plurality since the count to determine which candidate to eliminate can be close or tied in any round, and an elimination change, even in early rounds, can change the ultimate winner. Although at first glance ranked-choice voting may seem like an improvement, further investigation reveals serious problems. These problems are present no matter how loudly some support ranked-choice voting. There are better alternative election methods. Interested readers may look up “approval voting” and “score voting” at electology.org. Whatever methods are under consideration for Duluth, they should first be tried out repeatedly in less-critical situations than city elections. Until that time, Duluth should stick with its current imperfect but functional election methods.   Kathryn E. Lenz of Duluth is a retired mathematics professor.
I suspect I am among the unspecified mathematicians maligned by the March 13 Local View column, “Ranked-choice voting opponents just trying to sell you a bag of lies.” There is an informal group of us seeking to understand election methods, including costs and benefits, and to share our findings in order to help Duluth make informed choices.There are many methods of electing single winners. Let us consider three: plurality, plurality with runoff and ranked-choice voting, which is also called instant-runoff voting or single-transferable vote.In plurality, each voter votes for one candidate and the candidate with the most votes wins.In plurality with runoff, there is a primary plurality election followed by a runoff between the primary’s top two vote-getters.With ranked-choice voting, voters mark candidates in order of preference, sometimes up to a cut-off. In the 2013 Minneapolis mayoral election, voters ranked up to three candidates.   Ranked-choice voting elections are conducted in rounds. In the first round, each candidate’s votes are his or her total number of first-place rankings among the ballots.  Then, as well as in each subsequent round, the candidate with the fewest votes is eliminated, and for each ballot that contributed a vote to this candidate the vote goes to the ballot’s next ranked candidate not yet eliminated, or, if all the candidates on the ballot have been eliminated, the ballot plays no further role in the election. The final round is a contest between the two remaining candidates, and the one with the most votes wins. See, for example, the 2013 Minneapolis mayoral election rounds table at vote.minneapolismn.gov/results/2013/2013-mayor-tabulation.The pros of plurality include that it is simple to understand and verify, ballots are simple to fill out and votes can be tallied as they are received.Cons of plurality include that similar candidates can split votes, allowing neither to win, even if a majority supports the two candidates’ common platform. This often is referred to as the vote-splitting or spoiler problem.Pros of plurality with runoff include that it is simple, like plurality, and the runoff election produces a majority winner. Voters have an opportunity to become more informed about the two candidates who make it through the primary before voting in the runoff, and people can vote in the runoff even if they did not vote in the primary.Cons of plurality with runoff include the possibility of vote-splitting in the primary election, the potential for low voter participation in the primary, and the need for two elections.Ranked-choice voting avoids the spoiler problem in certain situations, as among its pros. It also allows voters to express preferences for multiple candidates. But its cons include its use of a complicated algorithm, its lack of transparency, its requirement for voter education and specialized software, and its need for all votes to be in before election tabulations can begin. In addition, disputed ballots, late ballots or vote integrity problems require restarting the process. The frequency of contested ranked-choice voting elections, including via recounts and/or lawsuits, may be higher than for plurality since the count to determine which candidate to eliminate can be close or tied in any round, and an elimination change, even in early rounds, can change the ultimate winner.Although at first glance ranked-choice voting may seem like an improvement, further investigation reveals serious problems. These problems are present no matter how loudly some support ranked-choice voting.There are better alternative election methods. Interested readers may look up “approval voting” and “score voting” at electology.org.Whatever methods are under consideration for Duluth, they should first be tried out repeatedly in less-critical situations than city elections. Until that time, Duluth should stick with its current imperfect but functional election methods.  Kathryn E. Lenz of Duluth is a retired mathematics professor.