How to Tally Ranked Ballots with Ranked Pairs

A > B > C
A > B > C, { A > B, B > C, A > C }
A > B > C = { A > B, B > C, A > C }
(0: A>B, 0: A<B), (0: B>C, 0: B<C), (0: A>C, 0:A<C)
(1: A>B, 0: A<B), (1: B>C, 0: B<C), (1: A>C, 0:A<C)
(100: A>B, 0: A<B), (25: B>C, 75: B<C), (100: A>C, 0:A<C)

Summary

  • Break each ranked ballot down into pairs of candidates. Add each pair discovered to a running tally of pairs.
  • After all ballots have been tallied, find the winning pairs.
  • Rank the winning pairs according to the number of times they occurred in the election.
  • Lock in each of the winning pairs one by one, starting with the most popular winning pair.
  • Check to see if the most recently locked-in winning pair contradicts more popular winning pairs that were locked in earlier. If it does, ignore it, and move to the next winning pair.
  • Inspect the locked-in winning pairs, convert them into a ranking of candidates.

Resources

Ranked Pairs Voting Explained Using The Ten Hundred Most-Used Words

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Carl Schroedl

Carl Schroedl

Science, Service, Software • Posts are my own, not my employer's • https://carlschroedl.com • @carlschroedl