How does RCV compare to approval, score, and Condorcet voting methods?
While no voting system is perfect, we believe Ranked Choice Voting is superior to all the alternatives, especially for use in political elections. First and foremost, RCV is tried, tested, and works well in practice. By contrast, approval, score, and Condorcet methods are not used anywhere in the world for governmental elections, so they are as yet unproven in real political contexts.
We believe a critical property of any voting system is that a candidate must win the election if they are the first choice of a majority of voters. Voting theorists call this simple property the majority criterion. RCV, Condorcet, and even plurality voting satisfy the majority criterion, but approval and score voting do not. In theory, a candidate could be the first choice of 99% of voters and still lose under approval or score.
Another property we consider important is later-no-harm. Later-no-harm means a vote for your second choice does not hurt the chance that your first choice is elected, your third choice cannot hurt your first or second choice, and so on. RCV satisfies later-no-harm, but under approval, score, or Condorcet methods, a vote for a less-preferred choice may unfortunately cause a more-preferred choice to lose. Without later-no-harm, voters feel pressured to bullet vote (vote for only their first choice) and are often lobbied to do so by the campaigns themselves. Case in point: the Dartmouth College Board of Trustees used to use approval voting for their elections, but once those races became competitive, they abandoned approval due in part to widespread bullet voting. The more voters bullet vote, the closer the system will resemble plurality voting, bringing us back to square one in terms of improving our voting system.
We also consider the Condorcet criterion to be important. This is the property that the candidate who would win a head-to-head race against every other candidate should always be elected. While RCV, approval, and score voting may all fail the Condorcet criterion on paper, in practice RCV has successfully elected the Condorcet candidate in virtually every election. Due to Condorcet’s violation of later-no-harm, and the additional complexity Condorcet requires to resolve cycles, we prefer RCV for political elections.
Lastly, approval, score, and Condorcet were all designed to be used in single-winner elections only. Ranked Choice Voting works well for both single-winner and multi-winner elections. For elections that involve a mixture of single-winner and multi-winner races, we strongly prefer the simplicity of using a uniform voting method across the board.
These reasons help explain why Ranked Choice Voting is the preferred voting method of the major electoral reform organizations around the world, including FairVote in the United States and the Electoral Reform Society in the UK. Again, no system is perfect, but if there's one thing all advocates of alternative voting systems agree on, it's that our current plurality voting method is the worst.
Sightline's Guide to Methods for Electing an Executive Officer
Why Approval Voting is Unworkable in Contested Elections
University of Colorado Student Government election highlights challenges for approval voting