How RCV Is Counted
In Ranked Choice Voting, voters rank as many candidates as they want in order of preference. If any candidate has a true majority (more than half) of the first preference votes, then that candidate is elected. Otherwise the RCV process builds a majority by eliminating the weakest candidates and transferring ballots cast for the eliminated candidate to the voters' next preference.
For voters, ranked choice voting is literally as easy as 1, 2, 3. Just rank your choices in order of preference. This sample ballot shows a voter who preferred Alice first, Carol second, and Bob third.
Counting Single-Winner Races
RCV ballots are counted in a series of rounds, as shown in the this flowchart and the videos below. First, all the first choices are counted, and if any candidate has a majority (more than half) the votes, that candidate wins. Otherwise, the last place candidate (the candidate with the fewest number of votes) is eliminated, and any votes cast for that candidate are transferred to the voter's next preference (if the voter chose to rank more candidates). After each round of counting, we check again to see is any candidate has a majority. The candidate with the majority, if any, is elected. Otherwise another candidate is eliminated and there is another round of counting.
Counting Multi-Winner Races
The single-winner race tabulation deals with the wasted vote "spoiler effect" problem by allowing ballots to count toward back-up choices when their first choice is defeated. In multi-winner races, it also handles a second, complimentary wasted vote problem: the "shoe-in effect." The shoe-in effect is the concern that a candidate will have too many votes — more than needed to win — and may take votes away from other deserving candidates. The RCV count deals with wasted votes for shoe-in candidates by transferring ballots, or fractions of ballots, from elected candidates to back-up choices that have yet to be either elected or defeated.
Check out these videos produced by our friends at Minnesota Public Radio that show the how votes are counted in single and multi winner Ranked Choice Voting elections.
For further reading, FairVote offers another multi-winner RCV example.