Single Transferable Vote (STV)

© CGP Gray, Youtube
© CGP Gray, Youtube
© CGP Gray, Youtube
© CGP Gray, Youtube
  1. Voters each cast a single preferential ballot, in a single voting round, rating the candidates according to the given voter’s first, second, third, and so forth preferences.
  2. The ballots are evaluated in multiple counting rounds.  In each round:
    1. For each candidate above above the threshold — using a weighting algorithm based on the number of ballots above the threshold — we reallocate ballots to other candidates according to voters’ subsequent choices;  otherwise
    2. For each candidate beneath the election threshold — having the fewest ballots — we reallocate their ballots to other candidates according to voters’ subsequent choices.


  • The first general observation is that, as for IRV / AV, a ballot’s full list of preferences is not necessarily used.
  • While STV is often called a PR approach, there is no mechanism here to allocate seats proportional to party standings.  It’s Multiple Representation (MR), but not PR.
  • Votes are cast for individuals (who might or might not be identified with a given party), and are not explicit votes for a party.  This keeps the elected representatives fundamentally responsible to the voters, NOT their respective parties.

Condorcet Alternative

We can also use Condorcet/Ranked-Pairs as a multi-member system, to elect, say, n members:

  1. We take the n most-preferred candidates from the Condorcet/Ranked-Pairs outcome.
  2. There’s no “weighting” calculation, no “surplus” votes to be reallocated anywhere, and no progressive elimination.
  3. In one fell swoop we identify — and elect — the required number of members, having holistically considered all preferences from all ballots.

Next: Condorcet/Ranked-Pairs

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