How do the instant run-off elections work?

The instant runoff voting tabulates votes based on the principle that any vote cast for a last-place candidate shall be transferred to the next-choice candidate on that ballot until one candidate has a majority of votes. This ballot-count method duplicates what would occur if all voters participated in a graduated series of runoff elections.

Vote counting shall start with a tabulation of first-choice votes. If a candidate receives a majority of the first-choice votes, then that candidate shall be declared elected. If no candidate receives such a majority, then the candidate with the fewest first choices shall be declared defeated. Ballots cast for this defeated candidate shall be transferred at full value to the next-choice candidate marked on each ballot. Last-place candidates are eliminated and their supporters' ballots transferred to next-choice candidates who are still in the race in a similar manner until a candidate receives a majority of votes that have not been exhausted.

If a ballot has no more available choices ranked on it, that ballot shall be declared "exhausted."

If there are two candidates with fewest number of first place votes, the number of second-place votes are included. If that still doesn't break the tie, third-place votes are included, and so on. It's still possible, but highly unlikely, that there will still be a tie.

Example:

4 candidates, 50 voters

A: 22 first-place votes

B: 16 first-place votes

C: 6 first-place votes

D: 6 first-place votes

No candidate has a majority of the first-place votes. This voting method drops the one with the fewest votes. In this case, there are two. Which one to declare defeated? Since they have the same number of first place votes, the second-place votes for those two are considered for the tie-breaker.

C: 10 second-place votes

D: 13 second-place votes

C is eliminated and D remains. The 6 ballots that have C as their first choice are referenced for their second choice (they be come first choice votes now that C is no longer in the race, the 3rd place votes become 2nd, etc.)

Of those six votes, two have A second, and 4 have B second.

That gives the following:

A: 24 first place votes

B: 20 first place votes

D: 6 first place votes

Still no majority.

D is alone in last place, so D is eliminated. The 6 ballots that have D as their first choice are referenced for their second choice. Those votes are added to A and B. One of them will now have a majority or there will be a tie.

If there is still a tie, the one with the greater number of first place votes in the prior round is declared the winner—having more natural first place votes.



Article ID: 144
Last updated: 22 Jun, 2010
Revision: 1
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