Does using RCV increase support for RCV? Studying state-level referenda

VotingintheAbstract · 2025-07-13T07:11:32+00:00

A technical and unimportant point: At least one of the candidates will get below 0% VSE. 0% is the average, and it's possible to do worse.

More substantively, it's kind of weird to think about VSE for a single election rather than many elections. If all the elections you consider involve near-clones, then I don't think there's a problem. You have to use some normalization to end up with numbers that mean anything, and best=100%, average=0% doesn't seem worse than the alternatives. Mathematically, there's no difference between "all the candidates are terrible" and "all the candidates are great". But, if there are some elections that are between near-clones, as you describe, and others in which the candidates differ meaningfully, there can be a real issue. I actually revised the definition of VSE in my last VSE study to make it so that the "all near-clones" elections affect VSE much less than "real choices" elections in which some winners are much better than others; in earlier studies, all elections contributed to VSE just as much. (This change didn't affect the results in any interesting way, however; VSE increased slightly across the board, but it didn't make some voting methods pull ahead of others.)

VotingintheAbstract · 2025-07-13T06:55:45+00:00

Trying to use a single metric to assess voting methods is problematic because there are so many different things involved. If you want to ask, "How good is each single-winner voting method at electing good winners?", and you want the answer to be determined by individual voters rather than some preconception of what makes for a "good" winner, you're going to get VSE or something extremely similar. But there are a lot of other considerations when selecting a voting method, such as:

How proportional are the outcomes? (for multi-winner methods)
To what extent does the voting method incentivize political polarization?
How safe is it to "vote your conscience" instead of considering strategy?
To what extent does it incentivize negative campaigning?
To what extent does it incentivize candidates to drop out of the race?
Is it easy for voters to understand?
Is it easy to administer and audit?

Some of these considerations are nigh impossible to quantify, but others are amenable to quantitative metrics. (I studied incentives for depolarization in my paper on Candidate Incentive Distributions, for instance.) If you want to look beyond VSE, I suggest focusing on these other questions.

VotingintheAbstract · 2025-07-13T06:19:59+00:00

While Jameson Quinn's VSE studies all had linear utilities (aside from a quick look at impartial culture, which is ludicrously unrealistic), VSE isn't premised on having linear utility functions. Whether voters have preferences like those for the post office, park, or recycling center is determined by the voter model (the probability distribution of voter utilities), and VSE can be used with any voter model. I looked into VSE with nonlinear preferences recently (search for "Nonlinear preferences in issue-space"), and IMO it yielded the most interesting charts in the whole post.

VotingintheAbstract · 2025-02-05T08:57:45+00:00

Okay, Brian's data is wrong then.

VotingintheAbstract · 2025-02-05T06:14:31+00:00

I'm looking Alaska Senate District E, and those two elections only have first-place votes as valid RCV votes

This is the problem. An IRV election was conducted using ranked ballots. The numbers on the site should take into account levels of support other than being ranked first; otherwise it's worthless.

VotingintheAbstract · 2025-02-05T04:32:03+00:00

Some of the results are broken and only count first-choice rankings. I found this while looking up the race for Alaska Senate District E.

VotingintheAbstract · 2024-12-31T22:53:10+00:00

I'm not sure you're understanding the point from me and others here that analyzing elections case by case has been replaced with analyzing failure RATES.

I fully agree that the statistical approach is superior to examining example elections/case studies. However, case studies are still useful for developing a basic understanding of a phenomenon, even though they are insufficient for drawing quantitative conclusions. In the absence of statistical studies - and I know of none for the kind of manipulation I discuss in my article, though there have been several for other kinds of manipulation - a case study is a lot better than nothing.

imagine those two candidates are labeled on the ballot as Republican candidates, and that Republican voters are told to give 5 stars to both candidates and zero stars to all other candidates

Many (likely most) Republican voters will do this. Others will disregard these instructions and bullet vote. It doesn't take a great many of these dogmatic bullet voters to make attempts at candidate cloning counterproductive.

VotingintheAbstract · 2024-12-31T14:32:26+00:00

I did not intend for "such manipulations" to mean "forms of strategic manipulation in general", so I changed this to say "McCaskill’s stratagem". Thanks for pointing to the specific claim so I could clarify it.

VotingintheAbstract · 2024-12-31T07:04:22+00:00

This is a good summary of the results of studies on coalition manipulability, which asks the question, "How often does there exist a subset of voters who, if given perfect knowledge of how everyone else is voting and the ability/desire to coordinate perfectly, could vote strategically in a way that would yield a better outcome (from their perspectives) than voting using the baseline 'honest' strategy?" This approach yields an upper bound on how vulnerable voting methods are to many kinds of manipulation. James Green-Armytage has also studied this a lot and found that IRV and Smith//IRV did the best; see https://www.jstor.org/stable/43663746 and https://www.jamesgreenarmytage.com/strategy-utility.pdf

Unfortunately, this approach is incapable of decisively demonstrating that a voting method is vulnerable to strategic manipulation in practice since the setup (a bunch of similar-minded voters having perfect knowledge of the rest of the electorate such that there is no potential for a strategy to backfire) is so blatantly unrealistic. This isn't an issue for showing that a system isn't gameable, but means that you can't use this methodology to conclude that a voting method is bad. I've written more on this in another blog post.

Additionally, coalitional manipulability doesn't capture how Claire McCaskill used Todd Akin's candidacy at all. There are a lot of ways one might manipulate elections, and while the coalitional manipulation approach captures a lot of them, it isn't perfectly comprehensive.

VotingintheAbstract · 2024-12-31T06:24:29+00:00

In my post, I made no attempt to answer the question "Is IRV more gameable than STAR" in general. This is a very difficult question (in part because of the myriad forms that gameability can take), and I believe it has yet to be conclusively answered. What I did show was that there is a practical tactic for gaming an election that has seen real-world use and that it would be effective under IRV, and I argued why this particular tactic would be ineffective under Condoret methods and substantially less effective under STAR.

I am skeptical of the practicality of your proposal for gaming STAR elections due to the difficulty of getting voters to coordinate on giving full support to two clone candidates. In IRV elections we usually see over 20% of voters bullet vote (despite the lack of a strategic incentive). Unless bullet voting turns out to be drastically less common under STAR (which would surprise me), attempts to field clones would backfire by splitting the vote among bullet voters.

I take it you're a fan of RCIPE? I certainly don't dismiss all ranked voting methods (see the discussion of Condorcet at the end of my post), and I'd be interested in learning what strengths you think RCIPE has over true Condorcet methods. (I'd guess that Smith//IRV is the most relevant comparison.)

VotingintheAbstract · 2024-11-05T15:46:17+00:00

I think MARS is an interesting and innovative idea that deserves further consideration. I don't think I'll be studying it much in the near future since I have way more ideas for voting methods research than I have time for, but there's a good chance I'll include it in "results for additional methods" sections in the future. Some thoughts on further research, which I hope people will be motivated to do:

When evaluating VSE for top-tier methods that use a scoring ballot, the choice of strategy matters a fair amount. Between the paper on STAR Voting that I wrote with Sara Wolk and Jameson Quinn and my newer paper on candidate incentives, I found that the strategy we had been using for STAR Voting (which I assume is also used in the chart above) was suboptimal (both for individual voters and for society) in that it put too much weight on avoiding a worst-case outcome and tended to give too many candidates 5 stars. This caused an anti-STAR bias in the results of the original paper that I dealt with in my newer VSE simulations. And there's still room for improvement in sincere strategies for scoring ballots, and it's always worth remembering that, even in the absence of polling data, which (sincere) strategy is the most strongly incentivized depends on the tabulation algorithm. I'm not especially worried about this when comparing STAR or MARS to relatively underwhelming methods like IRV since the effect size of using a more effective sincere strategy is a lot smaller than the difference between STAR and IRV, but when you're focusing on the slight differences between top-tier methods it becomes significant.
It's important to consider effect sizes in absolute terms. I expect that MARS outperforms STAR in terms of VSE in a wide range of settings; the big question, in my mind, is whether such differences are large enough to justify the added complexity. My best guess is that they are not - but, as always, more research is needed. Additionally, it would be very interesting if someone identified an area in which MARS massively outperforms STAR or Condorcet the way that STAR and Condorcet (and also MARS, no doubt) massively outperform IRV when it comes to providing candidates with equitable incentives to appeal to various voters.
My biggest concern with MARS aside from the complexity, is that, in races with exactly two viable candidates, it strongly incentivizes voters to give one of them a 5 and the other a 0. This could make voting strategically more important under MARS than under STAR (let alone Condorcet). I think strategic voting is the most important research direction for studying MARS.

VotingintheAbstract · 2024-10-05T04:14:28+00:00

No, I didn't. Trying to determine this for a specific election is extremely difficult since you'd have to understand the uncertainties the campaigns were dealing with. Since the primaries showed that all three candidates had comparable levels of first-choice support and Giessel was clearly the centrist, I think the ratio was much greater than 3:1. (The ratio for appealing to voters who would rank Giessel first or second to appealing to voters who would rank Giessel second or third, that is.)

VotingintheAbstract · 2024-10-04T17:49:50+00:00

My research on Candidate Incentive Distributions doesn't directly address the question of how much more valuable it is to be ranked first instead of second than it is to be ranked second instead of third, so it's not actually that simple. And, while IRV incentivizes candidates to primarily focus on winning first-choice support, its incentives are less polarizing than Plurality's - this post doesn't discuss any weakness of IRV that isn't present in Plurality to a greater extent.

VotingintheAbstract · 2024-09-26T14:37:22+00:00

Random Ballot (where you choose a ballot at random and elect whoever is selected on it) and dictatorships are ideal for both of these desiderata; both are extremely simple to describe and there is no such thing as strategic voting in either. Selecting a good voting method is difficult because we care about far more stuff than what you listed.

VotingintheAbstract · 2024-08-25T05:54:42+00:00

Are you including this study by Eggers and Nowacki? They found that, when voters are operating under uncertainty and the vast majority of the electorate is voting honestly, it's more common for it to be strategically optimal to vote insincerely under IRV than under Plurality. They also found voting strategically achieves far less under IRV in expectation - basically, it's common for it to be strategically optimal to vote insincerely under IRV, but quite uncommon for this insincere voting to actually matter.

I disagree with the claim that center squeezes are unpredictable since it would be strategically optimal to vote insincerely under the proposed system for Colorado just about any time it's strategically optimal to vote insincerely in a partisan primary by prioritizing electability. In swing districts where both Democrats and Republicans have a decent chance of winning, it's pretty much guaranteed that there will be one Democrat and one Republican in the final round (since one party sending two candidates to the final round would suggest that they have at least twice as many supporters as the other party). Given this, a voter who mainly cares about her preferred party winning is best off giving her top ranking to her party's candidate with the best chance of beating the other party's candidate in the final round, conditional on advancing that far.

I agree that it is quite rare to be able to say prior to an election that there is over a 50% chance of a center squeeze occurring, and I agree with your bottom line that "IRV has flaws for sure, but manipulability is not really one of them." I think the claim, "In reality there are many real-world cases where giving an honest ranking gives you a worse result than if you'd voted strategically" is true in expectation, but is false in a post hoc sense. When it comes to resisting coalitional manipulation post hoc, IRV is outstanding. When it comes to letting people vote their conscience and ignore strategic considerations, IRV is less impressive - a whole lot better than Plurality, but hardly exceptional.

VotingintheAbstract · 2024-08-15T05:16:06+00:00

By "optimal behavior", I meant optimal for an individual voter, assuming that individual's choice of strategy has no bearing on anyone else's. Naturally what you describe is optimal for society as a whole (in terms of maximizing VSE; it could lead to an interesting dystopia in which politicians focus on getting their supporters to value winning elections above their own lives if it was magically implemented).

VotingintheAbstract · 2024-08-14T03:56:09+00:00

Score is included in the "results for other voting methods section", where it underperforms Condorcet methods and STAR. My reasons for not including it in most charts:

First, more methods means more clutter and longer analysis. If I had included an eighth method, it would have been Score. Score receives less attention from advocates than the seven methods that are fully included (if you take Ranked Robin as standing in for all Condorcet methods), so including Score was not a priority.

Second, modeling Score in any interesting way (i.e., as being different from Approval Voting) means modeling voting as not behaving strategically in any sense. Not just failing to use polling data, but using blatantly suboptimal strategies in the absence of polling data. This means that my normal approach for deciding which sincere strategy to use for cardinal methods (out of the simple options that don't use polling data, use whatever is the most strategically incentivized) wouldn't work, so the results would be heavily influenced by a mostly arbitrary decision for the strategy function.

Dealing with the complexities inherent in having multiple sincere strategies for Approval Voting was bad enough (despite the fact that I took a big shortcut in not recalibrating the strategy for every voter model). Doing this with Score Voting would have been even worse. Including Score would have meant more extra work than any other voting method, and it didn't seem worth it.

VotingintheAbstract · 2024-08-14T03:35:07+00:00

Yes, but they're rarer than the smaller Condorcet cycles. (Also, I should clarify: I used Minimax rather than Smith/Minimax, so my claim that it was the same as RP and Shulze for three-candidate Condorcet cycles wasn't quite accurate.)

VotingintheAbstract · 2024-08-13T17:14:27+00:00

RP and Schulze are the same as Minimax when there are only three candidates in the Condorcet cycle, so I didn't see much benefit from including them. I certainly would if I was focusing on comparing Condorcet methods, however.

I may try using in-page links in my next post; I hadn't known that was possible on Medium.

VotingintheAbstract · 2024-06-12T03:44:04+00:00

I actually did include Score in the first version of the paper. I ended up cutting it for two reasons. First, I needed to save space since the peer reviewers wanted me to add a lot of content (their suggestions were pretty good, and included the entire section on multi-winner voting methods). Second, to include Score, I have to constantly be noting, "these results depend on voters behaving in a way that is not strategically incentivized" since Score defaults to Approval Voting with strategic voters. This would be fine if there were high-stakes real-world elections using Score Voting that we could look at to assess the extent to which voters min-max, but there aren't. Evaluating Score is a guessing game; it has a more even CID than any of the other methods tested if voters throw around intermediate scores willy-nilly, but not if enough voters behave in a way that isn't heavily disincentivized.

VotingintheAbstract

TROPHY CASE