IRV vs Plurality Voting Comparison

Can Ranked-Choice Voting Heal Political Divides? The Surprising Science Behind IRV

Rhea Morgan in Politics & Policy August 2025 • 4 min read.

"Discover how instant runoff voting (IRV) moderates political outcomes, fostering compromise and reducing polarization, according to new research."

In an era marked by increasing political polarization, finding effective ways to bridge divides has become more critical than ever. Instant runoff voting (IRV), also known as ranked-choice voting, has emerged as a promising alternative to traditional plurality voting systems. Advocates claim it encourages moderation, reduces negative campaigning, and ultimately leads to more representative outcomes. But does IRV really live up to the hype?

While IRV has gained traction in various municipalities and even a few states, theoretical backing for its purported benefits has been limited. Existing evidence often relies on case studies and simulations, leaving a gap in our understanding of how IRV functions at a fundamental level. Is there something inherent in the structure of IRV that promotes moderation, or are its observed effects simply the result of how candidates and voters behave under the system?

A new study tackles this question head-on, providing compelling evidence that IRV does indeed have a moderating effect relative to plurality voting. By developing a precise mathematical framework, the researchers demonstrate how IRV can prevent extreme candidates from winning, even when voters and candidates are drawn from polarized distributions. The findings offer valuable insights into the potential of IRV to foster compromise and create a more balanced political landscape.

How Does Instant Runoff Voting (IRV) Work?

Before diving into the study's findings, let's quickly recap how IRV works. In a traditional plurality voting system, voters simply choose their favorite candidate, and the candidate with the most votes wins. IRV, on the other hand, asks voters to rank candidates in order of preference. If no candidate receives a majority of first-place votes, the candidate with the fewest first-place votes is eliminated, and their votes are redistributed to the next-ranked candidate on each ballot. This process continues until one candidate obtains a majority and is declared the winner.

This seemingly simple change in voting mechanics can have profound effects on election outcomes. Proponents argue that IRV incentivizes candidates to appeal to a broader range of voters, as they need to secure not only first-place votes but also second and third-place rankings. This, in turn, is believed to encourage moderation and reduce the likelihood of extreme candidates winning.

Encourages Compromise: Candidates aim to be acceptable to a wide range of voters.
Reduces Negative Campaigning: Incentivizes candidates to maintain broader appeal.
Elects More Moderate Winners: Lessens the chance of polarizing figures winning.

The recent study provides a theoretical foundation for these claims, demonstrating that IRV has a moderating effect in a precise, mathematically defined sense.

The Future of Voting: Is IRV the Answer?

The research provides a compelling case for the moderating effects of IRV, adding a crucial theoretical layer to the ongoing debate about electoral reform. While IRV is not a panacea for all that ails our political system, it offers a promising mechanism for fostering compromise and reducing the influence of extreme voices. As more municipalities and states consider adopting IRV, this study provides valuable insights for policymakers and voters alike.

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This article is based on research published under:

DOI-LINK: https://doi.org/10.48550/arXiv.2303.09734,

Title: The Moderating Effect Of Instant Runoff Voting

Subject: cs.ma cs.gt econ.th

Authors: Kiran Tomlinson, Johan Ugander, Jon Kleinberg

Published: 16-03-2023

Everything You Need To Know

What is Instant Runoff Voting (IRV) and how does it differ from traditional plurality voting?

Instant Runoff Voting (IRV), also known as ranked-choice voting, is a voting system where voters rank candidates in order of preference. Unlike traditional plurality voting, where voters simply choose one candidate, IRV redistributes votes. If no candidate receives a majority of first-place votes, the candidate with the fewest votes is eliminated, and their votes are reallocated based on the voters' second choices, and so on, until one candidate reaches a majority. This process is repeated until a single candidate has a majority of the votes.

How does Instant Runoff Voting (IRV) promote moderation in political outcomes?

IRV encourages moderation because candidates need to appeal to a broader range of voters to secure not only first-place votes but also second and third-place rankings. To gain more votes, candidates may have to compromise or avoid extreme positions to be seen as acceptable to a wider electorate. This contrasts with plurality voting, where candidates can win by appealing to a specific base, often leading to polarizing figures.

What are the potential benefits of using Instant Runoff Voting (IRV)?

The adoption of Instant Runoff Voting (IRV) can lead to multiple benefits. It encourages compromise, as candidates aim to be acceptable to a wider range of voters. It reduces negative campaigning, as candidates are incentivized to maintain broader appeal to secure second and third-choice votes. Ultimately, it can elect more moderate winners, decreasing the likelihood of polarizing figures winning elections and promoting a more balanced political landscape.

Does the use of Instant Runoff Voting (IRV) completely eliminate political polarization?

No, the use of Instant Runoff Voting (IRV) is not a panacea for eliminating political polarization. While IRV can foster compromise and reduce the influence of extreme voices, it does not completely solve the issue. Other factors, such as societal divisions and media influence, continue to contribute to political polarization. However, IRV provides a promising mechanism for mitigating the effects of polarization within the electoral process by promoting moderation and encouraging candidates to appeal to a wider range of voters.

What does the study reveal about the effects of Instant Runoff Voting (IRV) on election outcomes and the future of voting?

The new study provides compelling evidence of the moderating effects of Instant Runoff Voting (IRV) by demonstrating how it can prevent extreme candidates from winning, even in polarized environments. This research adds a crucial theoretical layer to the ongoing debate about electoral reform and highlights the potential of IRV to foster compromise and reduce the influence of extreme voices. As more municipalities and states consider adopting IRV, this study provides valuable insights for policymakers and voters alike, suggesting IRV is a promising mechanism for improving the balance of political landscape.