When reformers start to build momentum to pass electoral reform, they often attract a Voting Theorist who comes out to argue for some other method. He (it’s often a he) uses technical jargon and mathematical theorems and points to Burlington Vermont’s 2009 mayoral election to prove reformers should support his preferred method and oppose Instant Runoff Voting (IRV). His preferred method could be Approval Voting, Score Voting, or Score Runoff Voting. (If you are lucky your campaign might attract one of each and they will argue with each other!)
He makes some interesting points, but also some convenient exaggerations and he cares more about math and theory than about human behavior and empirical evidence. Here are seven claims that advocates for Score Voting, Score Runoff Voting, and Approval Voting make about Burlington, Vermont in particular and IRV more generally, and responses.*
Score and Score Runoff proponents claim the Burlington election proves IRV is inherently flawed because it did not elect the Condorcet Winner—the candidate who would beat all other candidates in a head-to-head contest.
IRV fails the Condorcet criterion, and in Burlington it elected a non-Condorcet winner. But Score, Score Runoff, and Approval Voting all also fail the Condorcet criterion, so they could elect non-Condorcet winner as often—or more often—than IRV. If the Voting Theorist actually cared about guaranteeing the Condorcet winner, he could push for one of the methods that does that. But he doesn’t believe the Condorcet Winner is necessarily the “right” winner. (With good reason—Condorcet does not necessarily mean most support.) His objection that IRV fails this criterion falls a bit flat once you realize he actually doesn’t believe it is a critical criterion.
IRV has proven, in the real world, to elect the Condorcet winner much more often than plurality and runoff voting—the two systems in widespread use in the United States and Canada.
At first blush, this claim may read as 20 percent of all IRV elections will fail to elect the Condorcet Winner. But, no, the study found that it could happen in 20 percent of close elections, where three candidates each win about one-third of the vote. The vast majority of elections do not have three evenly matched candidates, so the occurrence rate in all elections is much lower. Second, the study counts cases where there was no Condorcet Winner—these cases are like games of rock-paper-scissors where no candidate can beat all others. But in these cases no method could elect the Condorcet Winner because there is not one.
In the real world, more than 99 percent of IRV elections pick the Condorcet Winner. In the 140 American elections have used IRV and released full data (thousands of elections have used IRV, but Condorcet failures are impossible to identify based on election results; you have to scrutinize the full data to find them.). Of the 140 elections with full data, all but one (Burlington in 2009—that’s why all the Theorists talk about it) elected the Condorcet Winner. For more information about what we can learn from Burlington—and what we can’t—see this detailed article on the topic.
That’s a real world occurrence rate of well less than 1 percent. If we eliminate the elections where a failure was impossible because there were only two candidates and look just at the 84 IRV races with three or more contenders, now the real world occurrence is just over one percent.
So yes, if more American and Canadian cities adopt IRV, some tiny fraction of elections will elect a non-Condorcet winner (although some of the those will be because there is no Condorcet winner). Probably around one percent of the time. And, as the below scenarios suggest, the Theorists’ methods might produce a non-Condorcet winner more often.
Score Voting advocates claim it is “likely” that Score and Approval would nonetheless have elected the Condorcet winner in Burlington. Score Runoff Voting advocates believe it is “very likely” that the Condorcet winner would have won. Or if he did not win, they will argue that with Score Voting, the voters would have felt the outcome was fair (but the same voters would have felt the same outcome was unfair under IRV).
Approval, Score, and Score Runoff Voting all fail the “Later No Harm” criterion, meaning giving an honest score to a less-preferred candidate could cause your favorite to lose. In elections with three strong candidates, many voters will score or approve only their favorite rather than cause their favorite to lose. If voters try to help their favorite win, Score and Approval methods will not only not elect a Condorcet winner, Approval and Score might do what plurality voting does and elect the least representative candidate, the Condorcet Loser—the one who would lose to both other candidate in a head-to-head. This is the worst possible outcome.
Instant Runoff Voting and other runoff methods (including Score Runoff), will never elect the Condorcet Loser.
None of the three methods the Theorists like have been used in a public election, so we don’t really know how voters and candidates would respond. But Approval Voting has been used in professional organizations and student body elections, so we know that in those settings most voters vote for just one candidate. Using the data from Burlington’s elections and some estimates about how campaigns and voters would use the three theoretical methods, here’s which candidate they might have elected in Burlington.
Approval Voting—most likely Republican Wright, possibly Progressive Kiss
In Approval Voting you can vote for every candidate you approve of. If Burlington voters gave an approval vote to every candidate they gave a rank to in the IRV election, Democrat Montroll would have won by a landslide 6,589 votes, Kiss would have trailed with 5,694 and Wright in last place amongst the top three candidates with 5,380.
But both the Republican and Progressive campaigns in Burlington would presumably have recognized this obvious threat from the center candidate and alerted their voters that, if they wanted their favorite to win, they should not approve the Democrat. If all voters had only approved their favorite of the top three contenders (they could also have safely approved of the Independent and Green candidates), Republican Wright would have won handily, 2,945 to Kiss’s 2585 and Montroll’s 2,045. Republican Wright was the Condorcet Loser—the candidate who would have lost to every other candidate in a head-to-head. So to the extent theorists believe that electing a non-Condorcet Winner like Kiss is a fail, electing Condorcet Loser Wright should be a catastrophe.
In student body and professional organizations that have used Approval Voting, often 80 to 100 percent of voters “bullet vote”—only approve of one candidate. If that pattern held in Burlington, Wright would have won. Even if Burlington voters were more generous with their approvals and only 70 percent bullet voted, Wright would still have won.
If Republican and Progressive voters voted only for their favorite, but all Montroll voters approved both him and their second choice, then Progressive Kiss would have won.
Score Voting—most likely Republican Wright
In Score Voting you can give each candidate a score, for example between one and nine. In Burlington, there were five candidates in the race and some voters ranked all five. If voters had given their first-ranked candidate a 9, their second choice a 6, third a 4, fourth a 2, and fifth a 1, Democrat Montroll would have won with a score of 41,020 to Kiss’s 37,515 and Wright’s 37,504.
But as in Approval Voting, the campaigns would have likely have recognized this threat (again, it’s rather obvious) and encouraged their voters to give low or no scores to all but their favorite. In fact, nearly 40 percent of Republican voters did not give either of the other two candidates a rank, so telling Republican voters not to score the other candidates would have been an easy sell. Even if some voters gave scores to all candidates so the average scores were just lower—say an average of 9, 4, 3, 2, 1—Republican Wright would have won.
Score Runoff Voting—likely Progressive Kiss, possibly Democrat Montroll
In Score Runoff Voting, as in Score Voting, you can give each candidate a score. But then the two candidates with the top total scores advance to an automatic runoff. Score Runoff advocates prefer a scale of zero to five, so let’s say that voters’ honest scores were to translate their actual rankings for all five candidates into a 5 for their favorite, 4 for their second, 3 for third, 2 for fourth, and 1 for fifth. Democrat Montroll and Progressive Kiss would have gone to the instant runoff where Montroll would have won.
Again, the campaigns would have understood the threat and likely let voters know they should give their favorite a 5 and their back-up a 1. This would minimize the chance their back-up would bump their favorite out of the runoff, but still give themselves a vote in the instant runoff in case their favorite didn’t make it. If everyone voted this way, Progressive Kiss would have won. Just like in IRV. Even if about half the voters didn’t get the strategy—say, that, within the top three contenders, voters averaged a 5 for their favorite, a 1.5 to their second-choice and 0.6 to their third—Kiss would have won.
Or say Republican and Democratic voters gave their second-choice an average of 2, but the Democrat didn’t spread the strategy since he was polling in third place, so his voters gave an average score of 3 to their second choice. Kiss would have won—the same as IRV.
We're in our Spring Fund Drive—make a gift now to support more research like this!
Or say polling showed voters that the Democrat would clearly beat the other candidates in a head-to-head. Republican and Progressive voters would realize their best bet was to keep the Democrat out of the runoff. They could strategically give the Democrat a low score and give their opposition candidate a high score, in hopes of sending the weaker opponent to the runoff where their favorite could defeat him. If even one-third of voters pursued this strategy, Wright and Kiss would have gone to the runoff and Kiss would have won.
Voting Theorists claim that Score Voting, which has never been used in an election, “appears to inspire honesty to a surprisingly large degree.” Some Score Runoff Voting Theorists confidently claim that with Score Runoff (a.k.a. Star) Voting it is always safe to vote honestly because strategic voting doesn’t work.
Sorry, strategic voting can work in every system. As the above scenarios show, strategic voting would have worked in Burlington in all the proposed methods.
Although honest voting was clearly the best strategy for 83 percent of Burlington IRV voters, critics focus on the 17 percent of Burlington voters whose favorite was Republican Wright and whose least-favorite was Progressive Kiss. Had these voters somehow known the Republican (who was polling first place) would lose, they could have strategically ranked the Democrat first to send him to the runoff instead of the Republican and at least keep the Progressive out of office. But the same strategy would have worked under Score Runoff Voting. Republican voters could have strategically inflated the Democrat’s score and also strategically given a low or no score to the Republican to boost the Democrat into the runoff where he could beat the Progressive.
IRV eliminates what most people think of as the spoiler effect, where a minor party candidate splits votes with a similar major party candidate, causing the other major party candidate to win with less than a majority. The 2000 American presidential election between Bush, Gore, Nader is the classic example. Oregonians may think of the 1990 Gubernatorial election where a conservative Independent split votes with Republican David Frohnmayer, allowing Democrat Barbara Roberts to win with less than 46 percent.
The mathematical definition is the independence of clones criterion: the winner does not change due to the addition of a non-winning candidate who is similar to a candidate already present. IRV passes this criterion: if Gore was going to beat Bush, Nader joining the race wouldn’t have changed that with IRV.
But IRV critics are implicitly re-defining “spoiler effect” to mean: the winner does not change due to the addition of a non-winning candidate even one dissimilar to the winner. By this definition, critics are correct that the Republican “spoiled” the election for the Democrat in Burlington.
But a Republican acting as a supposed spoiler to a Democrat was not a real problem since the Progressive winning was still representative of the majority of voters who leaned left. The similar-candidate spoiler is worrisome because it leads to an unrepresentative result.
Score Runoff advocates say Burlington had an unrepresentative outcome because not all votes were equal—voters for Republican Wright and Progressive Kiss only had their vote count for one candidate, whereas voters for Democrat Montroll got to vote for him, and then for someone else once Montroll was eliminated.
Wrong. IRV counts votes in rounds, just like a primary and a general. If your favorite advances you vote for him in the first round (primary) and in the next round (general), but if your favorite is eliminated after the primary, you have the chance to choose between the candidates in the next round. Everyone gets one vote per round, although some voters just get to vote for their favorite twice, just as they do in primary and general elections now. Two stage runoffs do, in practice, give voters who vote in the primary two bites at the apple while voters who only vote in the general only get to vote in that one round. By letting voters rank their preferences on a single ballot, IRV ensures that everyone who votes in that single election gets an equal voice.
Take note: this is actually a problem for Score voting methods which do let some votes count more than others, because you can give a candidate a score of, say, 8, which will count for twice as many points as another voter’s 4.
Anthony Gierzynski, the lead author of the Score Voting critique of the Burlington election, actually prefers plurality voting. He appears to have paraphrased the guy in the XKCD cartoon below and said “I prefer Plurality Voting, but since Burlington seriously did Instant Runoff, then I’ll argue for Score Voting instead.” He thinks IRV’s flaw is that it allows the Progressive Party to run candidates who compete with Democratic candidates. Plurality voting should force Progressives to become a part of the Democratic Party and then Democrats like Montroll could win. I’m sure you’ll be surprised to learn that Gierzynski was the Democratic candidate for the Vermont legislature in 2002 and lost to—guess who?—Progressive Bob Kiss.
If Americans were happy with the Democratic and Republican candidates, they would just vote for them and this whole argument would be moot. But Americans are not happy—close to half don’t affiliate with either party. Candidates outside the two major parties, or on the wings of the major parties, can broaden the number of issues and solutions that are discussed. IRV can enable more voters to cast a vote for a candidate they are genuinely excited about.
IRV has largely withstood the tests of real elections.
I hope, my dear fellow nerds who have read this far, it is clear I am not saying IRV is perfect. Indeed, no single-winner system can overcome all forms of strategy nor guarantee the “right” winner, especially because there sometimes isn’t one (recall rock-paper-scissors).
But the claims about Burlington and IRV all have something in common: they are attacking a reality in favor of a theory. After hundreds of public IRV elections, Burlington happened and now critics can point to it. But after hundreds of Score or Score Runoff or Approval Voting elections, would one of them elect a non-Condorcet winner? Probably yes. But no public elections have happened, so the Voting Theorist can blithely claim his method would “likely” elect the Condorcet winner and “always” encourage honest voting. IRV is like a real building that has been through decades of use and stood up to the tests of weather and gravity. It’s easy to point out the tiny cracks. Untested methods are like architectural drawings, perfect in every colored pencil detail, but who knows what will happen when they exist outside of imagination and paper.
Maybe some of those theories will work out in the real world. But in the meantime, don’t let the Voting Theorists derail real-world reform.
*Note that IRV advocates now prefer the term Ranked-Choice Voting (RCV) and Score Runoff advocates now prefer the term Star Voting, but I use IRV and Score Runoff throughout for clarity.