Ranking your vote
In a multi-seat RCV election, you rank your preferences the same way you do in a single-seat election, marking a first choice, a second choice, a third choice, etc.
How your vote is counted
To win, candidates must receive a minimum threshold of support. Some candidates might win with first-choice support, but most depend on second and third choices as well. The counting process is similar to single-seat elections, with the addition of transferring a winning candidates' surplus votes to second preferences to make sure that no votes are wasted.
Here's how it works:
1. Set the threshold to win. To fill 3 seats, it is 25% + 1 vote [1/(3+1) + 1]. To fill 2 seats, it is 33% + 1 [1/(2+1) + 1].
2. Tally first choices for all candidates and determine if any candidate has reached the winning threshold:
- If no candidate reaches the winning threshold in the first round, the last-placed candidate is defeated and the ballots for this candidate are reassigned based on the next choices on those voters’ ballots (just as in a single-seat race).
- If a candidate reaches the winning threshold, he or she wins. Any “surplus” votes that candidate has are reassigned proportionally to the next choices on those voters’ ballots. In the example graphic below, Carlos won 18 (or 40%) more votes than needed to win, so 40% of each vote for Carlos is reassigned to those voters' second choices. Of the 45 people who ranked Carlos #1, 15 ranked David #2; 40% of 15 is 6 votes, so David is therefore awarded 6 more votes.
3. This process of electing and defeating candidates and reallocating ballots continues until all seats are filled.
Imagine it like this: You have $1.00 to buy your favorite candy bar. But if that candy bar only costs 60 cents, you get to put your other 40 cents toward your second favorite candy bar. The same process applies here: If your #1 candidate reaches the threshold of votes needed to win but has 40% more votes than needed, 40% of your ballot (and of all the voters who ranked that candidate #1) is awarded to your second choice.
In multi-seat races, RCV:
- Ensures more people elect the winners. In a single-seat race, at least 50% of the voters will elect the winner. In a two-seat race, at least 66% will help elect the winner and in a three-seat race, at least 75% and so on.
- Wastes fewer votes. Any surplus votes a winner doesn't need are reassigned to remaining candidates until all seats are filled. This ensures that the majority of voters elect the majority of candidates while also giving smaller voting blocks an opportunity to elect someone they voted for.
- Makes sure your first choice can’t be harmed by your second or third choice. Under the traditional plurality-at-large system, voting equally for more than one candidate can harm your preferred candidate. The only way to prevent this from happening is to bullet vote, which is a common strategy under traditional voting. With RCV, your 2nd choice cannot harm your 1st choice – it only counts once your 1st choice is elected or defeated. Your 3rd choice only counts when your 2nd choice is elected or defeated.
For more information, check out this MPR video on how RCV works in multiple-winner elections.