Our Voting System Is a Loser

An article featuring Range Voting is in the news. William Poundstone is interviewed by Mother Jones. This is also featured on Slashdot.

The basis for the coverage is Poundstone’s new book Gaming the Vote: Why Elections Aren’t Fair (and What We Can Do About It)

From the MotherJones interview:

It’s heartening to know, as primary season begins, that ours may be the worst of all the voting systems in common use. That’s the takeaway from Gaming the Vote: Why Elections Aren’t Fair (and What We Can Do About It), the latest of eleven books by William Poundstone, a professional skeptic who studied physics at the Massachusetts Institute of Technology before he began pumping out nonfiction in 1982.

Poundstone became interested in voting theory after reading about Arrow’s Impossibility Theorem, a 59-year-old paradox wherein economist Kenneth Arrow, now a professor emeritus at Stanford University, identified what he perceived as a fundamental flaw in our democracy: Put simply, he argued that devising a perfectly fair voting system is mathematically impossible.

Mother Jones: Is there a way around Arrow’s Impossibility Theorem?

William Poundstone: For decades, there was almost a kind of despair among voting theorists of getting any better system than we had. What’s interesting, though, is that the impossibility theorem doesn’t apply to systems where you score the candidates rather than rank them. With scoring, you’re essentially filling out a report card—if you think there are two candidates who deserve four stars you can give them both four stars—whereas with ranking you have to artificially give one a number one and one a number two. That turns out to be crucial.

MJ: And yet plurality voting—where a person can vote for only one candidate for a particular office—is the most common system in use. What’s wrong with it?

WP: Whenever you have two candidates whose support overlaps, that’s bad for both of those candidates, the obvious example being Nader and Gore in 2000. So a candidate can be a spoiler and cause the second most popular candidate to win. This is something that’s been appreciated at least going back to the 18th century, and people have tried to devise different ways of dealing with it, but for a very long time this was one of those unsolvable problems.

And some more:

MJ: You seem to favor the emerging system of range voting.

WP: Range voting is the newest in the sense of people being aware of it and promoting it: If you’re rating a video on YouTube you give it one to five stars, and they take that information and show you the average score of all the people who bother to rate it. We use it with a report card. The valedictorian of a school is the winner of a range vote by the teachers for each of their classes. In the Olympics, they hold up those cards to rate someone’s performance—that’s another example. People are pretty familiar with the idea. Nobody has given a convincing argument that there’s anything seriously wrong with it—the one thing you sometimes hear is it’s complicated, but that’s about it.

I’ve been following Range Voting for a few years and I find the statement that “Nobody has given a convincing argument that there’s anything seriously wrong with it” to be remarkable and false. I say this as a supporter of range voting. The main argument that I hear against Range Voting is that is that it encourages people to partially abstain by not voting max-score or min-score for every candidate. I actually agree with this criticism in that I think that voting instructions ought to be clear that any vote that is not cast as a max-score or min-score is effectively a partial abstention. With appropriate voting instructions Range Voting could be considered Approval voting that allows for partial abstentions.

Although I could support Range Voting, I think that Approval Voting is a more practical reform that we should aim to achieve first. It is extraordinarily simple and a very good improvement over plurality and instant-runoff-voting.

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4 responses to “Our Voting System Is a Loser

  1. I see what you call “partial abstention” as a big plus. What it is really doing is measuring how strongly the person feels about each individual. Thus, if you win with a rating of 5.1 or so, that means that while you won, people really didn’t feel very strongly for you. Thats a significant amount of information. As the winning candidate, you can’t just claim that because you “won” you were given a mandate to do X.

    There used to be a system for board room voting where everyone turned a nob, and that either increased or decreased the voltage on the line depending on which way you twisted the nob. At the end you could measure how strongly opposed or for it the board was by measuring the current. Range voting is very much the same sort of idea.

  2. Also, are you really abstaining at all?

    If you vote 6 for candidate 1 and 4 on 2, even if that’s below 1 and above for 2, you still add less to 2 than you take away from 6, don’t you? If you assume both are lower/higher then you add/subtract more/less than the other candidate. Perhaps I am making a logical error (I was up late last night), but I don’t really think its abstaining per se.

  3. Rick: I don’t follow your second comment.

    Renaming candidates to letters…:

    >If you vote 6 for candidate A and 4 on B
    Assume that we are using Range with scores 0-9.

    If a voter like this discovers that B won and that A was close to winning, that voter might be angry that they did not instead vote 9 for A and 0 for B.

    I think that it is good and fine that a voter is allowed to vote for/against candidates with less then full strength but I think that as system designers we should work to make sure that the voter is aware that they made a vote with weaker strength then they could have made.

  4. A comment by me to the slashdot article:

    >[ben there]Might as well just go with the simpler Approval voting… It’s simpler, and
    >more effective in my experience.

    I partially agree. The most effective strategy under Range voting is to always vote max or min score for each candidate that you think is a real
    contender to win. Any other vote could be considered a partial abstention.
    If the voting instructions are poor or minimal many voters will accidentally partially abstain which will understandably make them angry. But if the instructions are well written then I do not think that this will happen to a significant degree.

    I like Approval voting but I see allowing partial abstentions as being a small improvement. I don’t like the idea of encouraging frequent accidental partial abstentions so my support for Range Voting is very sensitive to the context and voting instructions.

    See also the Range Voting advocacy site’s comparison of Range vs. Approval and make up your own mind:
    http://www.rangevoting.org/rangeVapp.html

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