This section examines how voters interact with the ranked ballot, and how many voters end up electing a candidate they had ranked highly.
We define "consensus value" as the proportion of voters who ranked the winner as their first, second, or third choice. We use consensus value as a measure of how much support the winning candidate garnered from the community as a whole. This measure is intrinsic to RCV and provides valuable information on how many voters found a winning candidate acceptable.
For more details on consensus value, see our spreadsheet of consensus values for single-winner RCV races.
The benefits of RCV are only applicable to the extent that voters use the ranked ballot effectively. Effective ballot use means ranking candidates beyond a first choice where doing so is advantageous, and avoiding errors which result in ballot invalidation.
All ballot types result in some number of errors in voting. In single-choice elections, ordinarily only overvotes - votes invalidated due to a voter attempting to vote for more than one candidate - count as ballot errors. In RCV elections, voters may make different kinds of deviant marks, including ranking the same candidate multiple times, skipping rankings, or including overvotes at later ranking orders. However, most of these do not impact the vote being counted as the voter intended. Only first-round overvotes can be fairly compared with errors in single-choice elections, since those are the only errors that, in both systems, invalidate the ballot entirely.
This section examines research into voter error as a measure of voter participation in the election process.
Kimball, D & Anthony, J. October 2016. Voter Participation with Ranked Choice Voting in the United States.
Neely, F & McDaniel, J. 2015. Overvoting and the Equality of Voice under Instant-Runoff Voting in San Francisco.
Burnett, C & Kogan, V. 2015. Ballot (and voter) “exhaustion” under Instant Runoff Voting: An examination of four ranked-choice elections.
FairVote’s own analysis shows that 18% of RCV races in the US have resulted in a winner who did not secure a majority of first-round votes. This drops to 13% when only considering races in which the voter was allowed to rank as many candidates as they choose. FairVote recommends jurisdictions allow voters to rank as many or as few candidates as they like. Read more on majority winners in the Who Wins RCV Races section.