Single transferable vote: Difference between revisions
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15 D>A>B>C</blockquote>E has a Droop quota (51 votes) so they win, and their 51 supporters' ballots are spent. Then we run a majority-passing single-winner method, say, [https://en.m.wikipedia.org/wiki/Mutual_majority_criterion#Minimax Minimax] on the remaining 100 ballots, and D wins despite there being a Droop solid coalition and thus a [[Mutual majority criterion|mutual majority]] of 52 voters for (A, B, C). Only a mutual majority-passing single-winner method would guarantee one of A, B, and C wins.
This modification to STV addresses to some extent one of the criticisms made by STV advocates about single-winner methods other than IRV:<blockquote>Furthermore, approval, score, and Condorcet were all designed to be used in single-winner elections only. Ranked choice voting works well for both single-winner ''and'' multi-winner elections. For elections that involve a mixture of single-winner and multi-winner races, we strongly prefer the simplicity of using a uniform voting method across the board.<ref>{{Cite web|url=https://www.fairvote.org/how_is_rcv_better_than_approval_score_or_condorcet_voting_methods|title=How is RCV better than Approval, Score or Condorcet voting methods?|last=FairVote.org|website=FairVote|access-date=2020-05-19}}</ref></blockquote>{{sectstub}}
== Notes ==
STV is a [[Largest remainder method|largest remainder method]] in the [[Party list case|party list case]]. This is because it gives each party as many seats as they have quotas, and when nobody can reach the quota anymore, it eliminates candidates until there are only as many candidates left as seats that are still unfilled, which de facto means that the parties with the most votes remaining (i.e. largest remainders) will win, since they'll be last to be eliminated.
STV and IRV can be visualized using Sankey or flow diagrams. If, in a given round, a candidate reaches the quota (a majority in IRV), they win, and if more seats are to be filled, then a quota of their votes are spent. This could be visualized by arranging the candidates from most votes to fewest in each round, and then showing a threshold for how many votes the candidate with the most votes in that round needs to win, or even further, showing the quota needed for the top (number of seats to be filled) candidates to win. Here is one example: <ref>{{Cite web|url=https://www.reddit.com/r/dataisbeautiful/comments/8we8ep/sankey_diagram_of_results_from_maines_democratic/|title=r/dataisbeautiful - Sankey diagram of results from Maine's Democratic Gubernatorial Primary, the state's first election using Ranked Choice Voting [OC]|website=reddit|language=en-US|access-date=2020-05-19}}</ref>
STV passes [[PSC]] regardless of the method used to decide which candidate is to be eliminated next, because for a solid coalition comprising k quotas, once all but k of the candidates in the coalition are eliminated, at least one of the k remaining candidates will have a quota of 1st choices and win, with their surplus transferring if necessary such that another of the k candidates wins, etc. It passes the [[Droop proportionality criterion]] when the [[Droop quota]] is used, making it one of the few commonly discussed PR methods that guarantees that a majority will always win at least half of the seats.
STV has several variations that can be discussed. For example, Meek and Warren STV are variants of STV that attempt to make the process fairer, but at the cost of needing to be computerized to compute the result.
There is some discussion regarding how to make STV results more transparent, while limiting the ability of vote-riggers to identify specific voters by having access to all of the preference data. <ref>http://www.votingmatters.org.uk/ISSUE30/I30P2.pdf</ref>
=== Related Election Methods ===
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