What is Instant Runoff Voting?

Instant Runoff Voting (IRV) is a simple voting method used to select a single winner from a list of two or more candidates. By collecting more meaningful information from voters, it gives them a greater power of choice and measures their will more accurately. Invented in the United States, this method has been used in Australia and Ireland for many decades.

How does it work?

IRV allows voters to rank the candidates they find acceptable. To determine the winner, voters' first choices are counted. Votes for the last-place candidate are reallocated to the second choices on their respective ballots, and this process is repeated until someone has a majority.

Sample ballot

This is a ballot used to select a location for an IRV activists' meeting.

IRV Meeting Location Poll

Instructions:

  • Choose the meeting places you support in order of preference.
[_]San Francisco
[2]Monterey
[1] Los Angeles
[3] Sacramento

This voter prefers to meet in Los Angeles, could meet in Monterey or Sacramento, and does not support a San Francisco meeting.

Here is a sample count:

Round 1
Los Angeles
Monterey
Sacramento
San Francisco

San Francisco is ahead, but Monterey and Sacramento could be splitting votes for LA.

Eliminated Redistributed Votes
Sacramento

The colors correspond to the second choices of Sacramento voters. Sacramento was fairly evenly split, but its voters leaned toward northern California.

Round 2
Los Angeles
Monterey
San Francisco

Monterey still has enough votes to hand victory to LA.

Eliminated Redistributed Votes
Monterey

In fact, Monterey voters overwhelmingly favored San Francisco as their second choice.

Round 3
Los Angeles
San Francisco
All choices eliminated

San Francisco wins.