Vote counting explainer

Counting Method

• RCV123 uses the common ranked choice voting method of counting the first place votes, then eliminating the candidate with the fewest votes and reallocating those votes to the candidates ranked second on those ballots. This process repeats until one candidate exceeds 50%. The method is slightly different for single-winner and multi-winner contests.

Note on Tie-Breaking: Our method for handling ties is a unique feature of RCV123. See our Tie-Breaking Explainer for full details.

Single-Winner Contests

In a single-winner contest, a candidate is elected when they receive a majority of the votes (more than 50%). If no candidate has a majority in the first round, the candidate with the fewest votes is eliminated. The votes for that eliminated candidate are then transferred to the next-ranked candidate on each ballot. This process repeats in rounds until one candidate has a majority of the votes that remain in play, or until only two candidates are left, at which point the candidate with more votes wins.

In some cases, a ballot may become "exhausted" if all the candidates a voter has ranked have been eliminated. These exhausted ballots are removed from the total, which can lower the number of votes needed to win in later rounds.

Multi-Winner Counting

• The method we use to tabulate multi-winner contests is known as Single Transferable Vote (STV). (Specifically, RCV123 uses the Weighted Inclusive Gregory Method, a particular type of STV.)
• The Winning Threshold
  To be elected, a candidate must reach a certain number of votes, called a threshold. This is calculated with a formula:

  (Total Votes ÷ (Number of Seats + 1)) + 1, rounded up.

  For example, with 101 voters and 4 seats, the threshold is (101 / 5) + 1 = 21.2, which rounds up to 22. Any candidate reaching 22 votes is declared a winner. This formula ensures that no more candidates can win than there are seats available.

• Surplus Vote Transfer
  When a candidate receives more votes than the threshold, their "surplus" votes are transferred to other candidates.

  For example, if a candidate reaches 23 votes and the threshold is 22, they have 1 surplus vote. This surplus is transferred fractionally from all 23 of that candidate's ballots. In this case, 1/23rd of each vote's value would be transferred to that voter's next-ranked choice.

  This fractional transfer ensures that all of a winning candidate's supporters contribute equally to their election and have an equal portion of their vote carry on to help other candidates. This process helps achieve a more proportional outcome.

• Electing Winners
  Candidates are elected as soon as they cross the threshold. The counting continues until all seats are filled. If at any point the number of candidates remaining in the race is equal to the number of seats yet to be filled, all those candidates are declared elected. If the final seat is to be decided between the last two remaining candidates, the one with more votes wins. Winners are listed on the results chart in the order they were elected.

To see how this counting process was applied to a specific election, go to the Results page and expand the Show round by round totals table below the main chart. The results chart illustrates this same process with colored bars illustrating each round of counting. You can hover your mouse over any color segment to see which round it represents and the exact number of votes received in that round.