What’s the Best Voting System?

Last February I highlighted a New Yorker piece about instant runoff voting (IRV) in awarding the Oscar for Best Picture. (Kudos to author Hendrik Hertzberg for correctly predicting the winner: The Hurt Locker.)

As I said at the time, I think elections to public office would benefit from IRV as well:

Why? Because it eliminates the downside of voting for a third-party candidate. In a race between D and R, you may worry that voting for third-party candidate I is “throwing your vote away.” That worry disappears with IRV. You can give I your number one vote and either D or R your number 2 vote. If I loses in the first round, you’ll be disappointed. But you won’t have wasted your vote since your second-place vote now becomes operative.

I think that would be a substantial improvement over the winner-take-all vote tallying that dominates the American political system today. But would it be the best of all possible voting systems?

In this week’s New Yorker, Anthony Gottlieb answers no, pointing to a potential flaw in IRV:

Such transferrable-vote elections can behave in topsy-turvy ways: they are what mathematicians call “non-monotonic,” which means that something can go up when it should go down, or vice versa. Whether a candidate who gets through the first round of counting will ultimately be elected may depend on which of his rivals he has to face in subsequent rounds, and some votes for a weaker challenger may do a candidate more good than a vote for that candidate himself. In short, a candidate may lose if certain voters back him, and would have won if they hadn’t.

The practical importance of this theoretical concern is a matter of heated debate, much of which has focused on a 2009 mayoral election in which Burlington, Vermont used IRV (as it had in 2006). According to IRV detractors Burlington ran right into the “non-mononicity” issue, with the “wrong” candidate winning (at least by some voting metrics). IRV supporters reject that view. (Sorry, I haven’t had time to sort this through; if you are interested, just Google “Burlington 2009 election” and have fun.)

As best I can tell, however, both sides agree that the current system is flawed. For example, many of the IRV detractors believe we should adopt a different system: range voting, which allows voters to express how much they like or dislike a candidate. Rather than just ranking Oscar movies, for example, voters would award scores: (e.g., Hurt Locker 10 points, Up in the Air 9 points, Avatar 2 points). The movie with the highest score would win.

That would also solve my primary concern about not discouraging votes for third-party candidates. But perhaps range voting has other hidden problems as well? As Gottlieb notes there is a limit to how far theorizing can take us in this debate:

Mathematics can suggest what approaches are worth trying, but it can’t reveal what will suit a particular place, and best deliver what we want from a democratic voting system: to create a government that feels legitimate to people—to reconcile people to being governed, and give them reason to feel that, win or lose (especially lose), the game is fair. The novelty of range and approval voting in modern politics is so great that we can’t know how they’ll work out without running experiments.

Let me second that recommendation: more experiments with IRV, range voting, approval voting, and other innovations would be well worth the effort.

But I think we can take a pass on the voting system of old Venice, which Gottlieb describes as follows:

Thirty electors were chosen by lot, and then a second lottery reduced them to nine, who nominated forty candidates in all, each of whom had to be approved by at least seven electors in order to pass to the next stage. The forty were pruned by lot to twelve, who nominated a total of twenty-five, who needed at least nine nominations each. The twenty-five were culled to nine, who picked an electoral college of forty-five, each with at least seven nominations. The forty-five became eleven, who chose a final college of forty-one. Each member proposed one candidate, all of whom were discussed and, if necessary, examined in person, whereupon each elector cast a vote for every candidate of whom he approved. The candidate with the most approvals was the winner, provided he had been endorsed by at least twenty-five of the forty-one.

About Donald Marron 294 Articles

Donald Marron is an economist in the Washington, DC area. He currently speaks, writes, and consults about economic, budget, and financial issues.

From 2002 to early 2009, he served in various senior positions in the White House and Congress including: * Member of the President’s Council of Economic Advisers (CEA) * Acting Director of the Congressional Budget Office (CBO) * Executive Director of Congress’s Joint Economic Committee (JEC)

Before his government service, Donald had a varied career as a professor, consultant, and entrepreneur. In the mid-1990s, he taught economics and finance at the University of Chicago Graduate School of Business. He then spent about a year-and-a-half managing large antitrust cases (e.g., Pepsi vs. Coke) at Charles River Associates in Washington, DC. After that, he took the plunge into the world of new ventures, serving as Chief Financial Officer of a health care software start-up in Austin, TX. After that fascinating experience, he started his career in public service.

Donald received his Ph.D. in Economics from the Massachusetts Institute of Technology and his B.A. in Mathematics a couple miles down the road at Harvard.

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2 Comments on What’s the Best Voting System?

  1. Gottlieb's overly-complex description is of how the _electors_ were chosen, not of how the voting system they used worked.

    Contrast it with how the electoral college for our president is determined (remember: you have to describe 51 different systems; one for each state, and DC, and although most are similar, they each have their own quirks), and you'll find that it's in the same ballpark.

    The actual voting system used in Venice was quite simple though, and consists of just the last two sentences of that paragraph; a process which is quite a bit simpler than IRV, and quite a bit better: http://rangevoting.org/BayRegsFig.html

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