What are the pros and cons of ranked-choice voting compared to first-past-the-post voting?

Question

What are the pros and cons of ranked-choice voting (RCV) compared to first-past-the-post voting (FPTP), supported by research?

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Notes:

• I prefer answers supported by evidence, with data from actual RCV and FPTP implementations, rather than theoretical considerations, thought experiments and simulations.
• I am particularly interested in substantial and/or significant effects on the following variables, or their proxies:
  1. Approximation to the "ideal" voting systems, e.g., by the Condorcet winner election frequency.
  2. Election "fairness" or public perception of fairness.
  3. Electoral system satisfaction.
  4. Political polarization.
  5. Corruption Perceptions Index.
  6. Influence of money on politics.
  7. Income or wealth inequality.
  8. Chances of catastrophic political outcomes that follow, such as the wars, coups, mass killings or genocide such as the ones in the Nazi Germany or the USSR.*
• I realize the for some of these variables, the most I can hope for would be historical examples (due to a ridiculously low number of samples).
• Instant-runoff voting (IRV) is a of method of ranked-choice voting (RCV) that is most commonly used in government throughout the world. But IRV is not the only method of tallying ranked ballots and determining the winner. "IRV" (sometimes called "Hare RCV") should not be used interchangeably with "RCV", so please specify which term your are using.

*: Regarding "catastrophic political outcomes": For example, for Russia, what was the electoral system that last preceded the coming of Bolsheviks to power? Did the Russian Provisional Government in 1917 use RCV or FPTP? It was a weak government, and was thus relatively easily deposed by the Bolsheviks in the 1917 October Revolution. Same question about Germany's Weimar Republic as the Nazis were coming to power during political turmoil and infighting in the German ruling elite in 1918-1933. Was it RCV or FPTP while the democracy there lasted? After Adolf Hitler seized power, it became a moot point, of course.

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Similar questions:

(and the differences between them and the present question)

• What arguments are there against ranked-choice voting?

  • That 2017 question asks only about the cons of RCV, without emphasis on research evidence from the actual RCV implementations. To quote from it: "But my question is, what arguments have been made against ranked-choice voting. It seems like an obviously superior system to me."
  • The current question asks about the pros and cons of RCV. The pros are a critical part of my current question.
  • The current question prefers "answers supported by evidence, with data from actual RCV and FPTP implementations, rather than theoretical considerations, thought experiments and simulations." I am not convinced by some of the answers to the 2017 question that often (e.g., 1, 2, etc) present evidence of the precisely the type I discourage (e.g., simulations, theoretical considerations).
  • The 2017 question and its answers do not address many of the specific variables of interest, listed with numbers above (such as influence of money in politics, corruption perception index, inequality, etc).
  • In the 7 years that have elapsed since the 2017 question was asked, new evidence might have accumulated. New research has been done. New evidence has accumulated. New political entities have switched from FPTP to RCV. Although this great answer by endolith has been updated, not all answers were updated. It is time for a fresh look in 2024.

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Off-topic:

Answers to this question (I plan to ask this more specific and very distinct question as a separate question in the future):

What are the pros and cons of RCV as implemented by FairVote and others in various locations around the US, compared to the current commonly used system in the US (FPTP)?

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References:

I found several pro-RCV, biased reference sources, in bad need of more balanced evidence analysis:

It’s unclear how often single-choice plurality (our current voting method) or two-round runoff elections elect Condorcet winners because voters’ back-choices are not publicly disclosed.

84% of respondents in Payson, UT and Vineyard, UT reported they were satisfied with their voting experience after their first use of RCV in 2019.
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61% of Maine respondents said they want to see RCV maintained or expanded after their first use in 2018. Maine’s legislature then expanded RCV to include presidential primary and general elections, and its biggest city passed RCV for all offices with 81% of the vote.
...
94% of Santa Fe, NM voters were satisfied with their first RCV experience in 2018.

FairVote’s RCV Primer - FairVote is a pro-RCV organization that lists suspiciously few cons to RCV.

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Much more balanced comparison on RCV and FPTP, with a handful of pros of RCV (but not a wall of pros as in FairVote references above). This webinar mentions, for example, that RCV has a very strong effect on reducing strategic voting (at 38:00 in the video). The webinar discusses both pros and cons of RCV. It is far less biased than, for example many other RCV related websites, podcasts and videos.

"Ranked Choice Voting (RCV): A Better Alternative?" - The SC Humanities Electoral Initiative - YouTube - 1 hour 16 min video/webinar with academic experts on electoral systems.

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The results indicate that racially polarized voting did not decrease due to the implementation of RCV. Rather, the results show that RCV contributed to higher levels of racially polarized voting between white and Asian voters.

McDaniel, J. (2018). Does More Choice Lead to Reduced Racially Polarized Voting? Assessing the Impact of Ranked-Choice Voting in Mayoral Elections. California Journal of Politics and Policy, 10(2). http://dx.doi.org/10.5070/P2cjpp10241252 Retrieved from https://escholarship.org/uc/item/2gm5854x

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PARKS: But even experts who are more open-minded to the reform are skeptical it can bring about the sort of transformational change that some advocates promise. We heard from Larry Jacobs earlier. He's from the University of Minnesota, and he co-wrote a paper poking holes in a number of those claims. Most notably, he says there isn't much evidence at this point that ranked-choice voting actually decreases polarization.

"Ranked choice voting is being touted as a cure-all for U.S. deep partisan divides", NPR: December 3, 2023

Answer 1

RCV advocates are not entirely honest about failures of the Instant-Runoff (IRV) method nor that the method can be meaningfully corrected.

I had recently published a paper regarding RCV in the Springer journal, Constitutional Political Economy that had been invited by the editor of a special issue on voting methods.

I have also testified before both Vermont House and Senate Government Operations and have inspired the House bill H.424 to bring RCV to Vermont municipalities. I have also connected Nobel Laureate and Harvard professor Dr. Eric Maskin to both HGO and SGO, but the latter committee snubbed this world-renown voting and social-choice expert. But Dr. Maskin did testify before HGO about the recent (August 2022) RCV failure in Alaska (opponents have now successfully mounted a ballot question to repeal RCV).

To be clear, I am for RCV, I know exactly what we want it to do for us. But I also recognize the need for reform and have witnessed first hand the failure of RCV in Burlington Vermont in 2009, which is what I have written, published, testified, and presented about.

The purpose of RCV is, in single-winner elections having 3 or more candidates:

1. ... that the candidate with majority support is elected. Plurality isn't good enough. We don't want a 40% candidate elected when the other 60% of voters would have preferred a different specific candidate over the 40% plurality candidate. But we cannot find out who that different specific candidate is without using the ranked ballot. We RCV advocates all agree on that.

2. Then whenever a plurality candidate is elected and voters believe that a different specific candidate would have beaten the plurality candidate in a head-to-head race, then the 3rd candidate (neither the plurality candidate nor the one people think would have won head-to-head) is viewed as the spoiler, a loser whose presence in the race materially changes who the winner is. We want to prevent that from happening. All RCV advocates agree on that.

3. Then voters voting for the spoiler suffer voter regret and in future elections are more likely to vote tactically (compromise) and vote for the major party candidate that they dislike the least, but they think is best situated to beat the other major party candidate that they dislike the most and fear will get elected. RCV is meant to free up those voters so that they can vote for the candidate they really like without fear of helping the candidate they loathe. All RCV advocates agree with that.

4. The way RCV is supposed to help those voters is that if their favorite candidate is defeated, then their second-choice vote is counted. So voters feel free to vote their hopes rather than voting their fears. Then 3rd-party and independent candidates get a more level playing field with the major-party candidates and diversity of choice in candidates is promoted. It's to help unlock us from a 2-party system where 3rd-party and independent candidates are disadvantaged.

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In Burlington Vermont 2009 [and also more recently in the Alaska 2022 (August special election)], RCV (in the form of IRV) failed in every one of those core purposes for adopting RCV. And it's an unnecessary failure because the ballot data contained sufficient information to satisfy all four purposes, but the tabulation method screwed it up.

In 2000, 48.4% of American voters marked their ballots that Al Gore was preferred over George W. Bush while 47.9% marked their ballots to the contrary. Yet George W. Bush was elected to office.

In 2016, 48.2% of American voters marked their ballots that Hillary Clinton was preferred over Donald Trump while 46.1% marked their ballots to the contrary. Yet Donald Trump was elected to office.

In 2009, 45.2% of Burlington voters marked their ballots that Andy Montroll was preferred over Bob Kiss while 38.7% marked their ballots to the contrary. Yet Bob Kiss was elected to office.

[And more recently in August 2022, 46.3% of Alaskan voters marked their ballots that Nick Begich was preferred over Mary Peltola while 42.0% marked their ballots to the contrary. Yet Mary Peltola was elected to office.]

That's not electing the majority-supported candidate. Andy would have defeated Bob in the final round by a margin of 6.5% had Andy met Bob in the final round. The 3476 voters that preferred Bob had votes with more effect than the 4064 voters that preferred Andy. Each of the 3476 voters for Bob had a vote that counted more than the vote from each of the 4064 voters for Andy.

[Or in Alaska, each of the 79000 voters that preferred Democrat Mary Peltola over moderate Republican Nick Begich had a vote that effectively counted more than a vote from each of the 87000 voters preferring Begich over Peltola. Those are not equally-valued votes, not "One person, one vote".]

Then, because Kurt Wright displaced Andy from the final round, that makes Kurt the spoiler, a loser in the race whose presence in the race materially changes who the winner is. When this failure happens, it's always the loser in the IRV final round who becomes the spoiler.

[Similarly in Alaska, Sarah Palin displaced Nick Begich from the final round, which makes Palin the spoiler, a loser in the race whose presence in the race materially changes who the winner is.]

Then voters for Kurt that didn't like Bob and covered their butt with a contingency (second-choice) vote for Andy, found out that simply by marking Kurt as #1, they actually caused the election of Bob Kiss. If just one in four of those voters had anticipated that their guy would not win and tactically marked Andy as their first choice, they would have stopped Bob Kiss from winning.

[Similarly in Alaska, voters for Palin that didn't like Peltola and covered their butt with a contingency (second-choice) vote for Begich, found out that simply by marking Palin as #1, they actually caused the election of Mary Peltola. If just one in thirteen of those voters had anticipated that their candidate would not win and tactically (and insincerely) marked Begich as their first choice, they would have stopped Mary Peltola from winning.]

Like Nader voters that caused the election of George W in 2000. They were punished for voting sincerely. Do Republicans dare to run a candidate for mayor in Burlington? Last time they did, they were punished for doing so. And for voting for that favorite candidate.

But none of this bad stuff would have happened in 2009 if the method had elected Andy Montroll, who was preferred over Kurt Wright by a margin of 933 voters, who was preferred over Bob Kiss by a margin of 588 voters, and was preferred over Dan Smith by a margin of 1573 voters. If you take out any loser, the winner remains the same. No spoiler. Then, consequentially, there are no voters who are punished for voting sincerely, no incentive for tactical voting.

And it's this disincentivizing tactical voting ("Vote your hopes, not your fears") that supports the notion that 3rd party and independent candidates can have a level playing field with major party candidates. And that's what supports diversity on the candidate slate.

And, using the correct methodology, the Kurt Wright voters get to have their votes for their second-choice candidate be counted. That promise, that our second-choice vote counts if our favorite candidate is defeated, was not kept in 2009 for these Wright voters. But this reform would keep that promise where IRV failed to keep it.

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My submitted paper (that is not copyright limited and not behind a pay wall)

More links to other important documentation:

One page primer (talking points) on Precinct Summability

2022 Letter to Governor Scott (H.744 from 2021)

Templates for plausible legislative language implementing Ranked-Choice Voting

Partha Dasgupta and Eric Maskin 2004 Scientific American article: The Fairest Vote of All

[Articles regarding the Alaska RCV election in August 2022 that suffered a similar majority failure] :

Foley & Maskin: Opinion Alaska’s rankedchoice voting is flawed. But there’s an easy fix.

Graham-Squire & McCune: A Mathematical Analysis of the 2022 Alaska Special Election for US House

Alaska Tables

When Things Get Worse: The IRV Election in Alaska

Atkinson & Gantz: The flaw in ranked-choice voting: rewarding extremists

A Success in Alaska for Ranked-Choice Voting?

Answer 2

The German parliament 1918-1933 was elected by proportional representation, therefore neither RCV nor FPTP. The Reichspraesident (president; note that Hitler was chancellor, not president, at least as long s there were still elections - in fact he lost a presidential election against Hindenburg) was directly voted according to FPTP in the second ballot (which wasn't constrained to the two best earlier candidates). In the first ballot absolute majority was required, but never achieved. Hindenburg won with 51.5% in the second ballot 1932. –

I am however very skeptical about attributing any causality for what came afterwards to the voting system (even though I don't get why they wouldn't run the second president's ballot between the two leading candidates of the first ballot only).

Answer 3

So the other answer was about how the IRV method does not always elect the consistent majority candidate nor always prevents the spoiler effect and we didn't yet get to the issue of Precinct Summability. This is a component of process transparency that we don't wanna lose and we will lose it with IRV. Maine's and Alaska's statewide RCV (and big cities like NYC) are having major scaling up problems with IRV. They have to haul all of the ballot data to the seat of government and don't get results for several days. The results of the last election in Alaska were announced 15 days after the election. And there's no practical way to double check the numbers as there is now with FPTP. There are mathematical reasons why IRV is not precinct summable. With even just four candidates (or more), the number of summable tallies that each precinct would have to publish is unfeasible with IRV.

Precinct Summability is something we have right now with regular First-Past-The-Post and we will lose it with RCV unless we reform the method of RCV to the correct method (Condorcet) so that we can decentralize vote tabulation and publish pairwise vote subtotals at each polling place. Those pairwise vote subtotals can be added up and we can independently learn who wins the RCV election without getting it from an announcement weeks later by officials at the central tabulation location at the seat of government. We can independently double-check their numbers and confirm who won. But we lose that with the IRV method that FairVote and RankTheVote insist we use for RCV.

Would it be a big deal if the law were changed that no polling place can publish election results (for that polling place)? That, no longer, the public can use this preliminary and decentralized data to predict how any particular race will turn out? Or, to independently verify the outcome of a close election from that original data? Is losing this part of process transparency a small price? And is it a necessary price to pay?