Election System Reform: Instant Runoff Voting

In my first article I discussed the types of plurality-majority voting we use in this country and introduced the principle of proportional representation: majority rule with minority representation, in proportion to voting strength in the electorate. In my second article I described the three main systems of proportional representation: List PR, Mixed Member Proportional (MMP), and Choice Voting (CV). In this, the last article, I will discuss a relative of CV that can be used when a single winner is to be elected, as in an election for Mayor or President.

In CV the voter is presented with a list of candidates. The voter writes a "1" next to their first choice, a "2" next to their second choice (who they would want if their first choice were eliminated), etc., for as many choices as they desire. This system of marking ballots is called Preference Voting (PV), and can also be applied to a single-seat election. When so used, it is called Instant Runoff Voting (IRV), Alternative Vote (AV), or Majority Preference Voting (MPV).

As in CV, a threshold of election is established by dividing the number of ballots cast by one more than the number of seats to be filled (that is, by two), and then adding one. In other words, the threshold in Instant Runoff Voting is 50 percent plus one vote.

The ballots are then sorted by first preference. If no candidate has a majority, the candidate with the fewest votes is declared defeated, and his/her ballots are transferred to their respective second-choice candidates and added to the vote totals of those candidates. (If no second choice is indicated, that ballot is declared exhausted and set aside.) This process is repeated until one candidate achieves a majority of the ballots cast, or (in the case of many exhausted ballots) only one candidate is left. That candidate is the winner.

Note that a voter's first choice is not hurt by that voter also indicating a second choice, as the voter's ballot stays with his/her first choice until such time as the first choice is eliminated from the counting. Similarly, the incentive for negative campaigning is reduced, as a candidate may need the second choices of supporters of one or more opponents in order to win.

Instant Runoff Voting is used to elect the Australian House of Representatives and the President of Ireland, and by the National Organization for Women to elect their officers.

IRV is considered a plurality-majority system, as the winner has to receive a majority of the vote. Unlike First Past The Post, it is impossible for a fringe candidate to spoil the election for a mainstream candidate. And unlike the Two-Round System, there is no extra expense for the candidates (or the government) to hold a second election.

It must be noted that IRV is not a form of PR, and does not achieve the proportional results (more women and minorities) that PR does. However, it can be viewed as a first step in electoral reform, as it will reduce negative campaigning and (by eliminating runoffs) reduce the costs of elections.

The recent (October 1997) Ireland Presidential election provides a good real-life example of how Instant Runoff Voting works. This is how the votes tallied:

After the counting of first choices, Mary McAleese had the lead with 45.24% of the vote, but not a majority of the vote. Since the totals of the lowest three candidates put together were less than that of the candidate in second place (that is, no matter how the votes transferred they would all be eliminated), to save time they were eliminated as a group and their votes transferred to the respective next remaining choice. As it happened, more votes were transferred to McAleese than to Banotti, increasing her lead.

"Big deal", you might say. "The person who had the highest vote total after the first count won anyway. Why bother with second choices?"

Let's respond to that criticism by looking at the results of Ireland's previous presidential election in 1990. There were three candidates in that race:

After the counting of first choices, Brian Lenihan had the lead with 44.1% of the vote, and in a "winner-take-all" election would have been declared the winner, even though he did not have a majority. But that's not how Instant Runoff Voting works. Since Austin Currie had the fewest votes, his ballots were redistributed by their respective second choices. Most of them went to Mary Robinson, giving her a final count of 52.8% and making her the winner.

In a US-style election, Currie would either have spoiled the election for Robinson, or forced an expensive runoff. In Instant Runoff Voting, there's no such thing as a spoiler, and a second election is never necessary. The application to US elections is obvious.

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Steve Chessin is an Advisory Board member of Fairvote, and serves on the Board of Directors of Californians for Electoral Reform.