Single transferable vote: Difference between revisions
Add link to New York 1937-1947, remove some dead links and do general cleanup
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#Delilah
=== Setting the
When all the votes have been cast, a winning quota is set. The most common formula for the quota is the [[Droop
<!-- <math>\left({{\rm votes} \over {\rm seats}+1}\right)+1</math>. -->
floor(votes / (seats + 1)) + 1
Other quotas used include the [[Hare
<!-- <math>\rm votes \over \rm seats</math> -->
votes / seats
and the
<!-- <math>\rm votes \over \rm {seats+2}</math>. -->
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=== Counting The Votes ===
Process A: Top-preference votes are tallied. If one or more candidates have received at least as many votes as the quota, they are declared elected. After a candidate is elected, they may not receive any more votes (though see below for a
The excess votes for the winning candidate are reallocated to the next-highest ranked candidates on the ballots for the elected candidate. There are different methods for determining how to reallocate the votes. Some versions use random selection, others count each ballot fractionally.
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The degree of proportionality nationwide is strongly related to the number of seats to be filled in each constituency. In a three-seat constituency, using the Droop quota, about a quarter of the vote is "wasted". These votes may be for minor candidates that were not eliminated, or elected candidates' surplus votes that did not get redistributed. In a nine-seat constituency, only a tenth of the vote is wasted, and a party needs only 10% of the vote in a constituency to win a seat. Consequently, the best proportionality is achieved when there are a large number of representatives per constituency.
The proportionality of STV can be controversial, especially in close elections such as the
Advocates of STV argue that the apparent disproportionality in STV is indicative of poor support for the party's candidates in second and third preferences. They argue that the STV result is actually a more accurate estimate of the party's support than a simple tally of first-preference votes.
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Within each constituency, STV passes the [[Droop proportionality criterion]] when using [[Hagenbach-Bischoff quota|Hagenbach-Bischoff quotas]] (when doing so, it is suggested that a candidate win only if they exceed quota), because when all but k candidates of a solid coalition's supported candidates have been eliminated, one of the remaining candidates is now the 1st choice of over a quota of voters, and is thus elected, with their surplus votes flowing towards some of the other k candidates, and this repeating, until all k candidates are elected. This guarantees a majority will win at least half of the seats in each constituency.
== Potential for
The single transferable vote eliminates much of the reason for [[tactical voting]]. Voters are "safe" voting for a candidate they fear won't be elected,
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However, in older STV systems there is a loophole:
candidates who have already been elected do not receive any more votes, so there is incentive to avoid voting for your top-ranked candidate until after they have already been elected.
Note that in more modern STV systems, this loophole has been fixed. A vote receives the same fractional weighting regardless of when it arrives at the successful candidate. This modernisation has not been adopted in all STV systems.
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* New Zealand [http://www.stv.govt.nz], where STV is being used for the first time for district health board and some local authority elections in October 2004
* Northern Ireland, for local, Assembly and European elections
* The United States, where the only official governing bodies that use STV to elect representatives are the City Council and School Committee of
STV enjoyed some popularity in the United States in the first half of the 20th Century.
The method used for electing the Legislative Assemblies of Tasmania and the elections in the province of Alberta, Canada from 1926 to 1955.
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* Conceptually speaking, the candidates who are eliminated during the STV portion of the count could be said to be eliminated from contention for the first N - 1 seats, but still remain in contention for the final seat; though technically, it's possible for the final seat to be filled during the STV count itself (i.e. in a 2-seat election, 2 candidates might each have a quota of 1st choices and automatically win).<ref name="reddit pseudo">{{cite web | title=Pseudocode for STV with Condorcet for the final seat : EndFPTP | website=reddit | date=2020-02-08 | url=https://www.reddit.com/r/EndFPTP/comments/f0muwv/pseudocode_for_stv_with_condorcet_for_the_final/ | access-date=2020-02-10}}</ref></blockquote>Note that with this scheme, after all but one seat is filled, surplus distribution is only necessary when there is enough of a surplus to potentially help one of the uneliminated candidates get a quota.
If the single-winner method passes the [[majority criterion]], then this modification makes STV with Droop quotas become the single-winner method in the single-winner case, since a candidate with a Droop quota of 1st choices is the majority's 1st choice in the single-winner case. If STV with Hare
5-winner example:<blockquote>45 L1 > L2 > L3 > C > R2 > R1
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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 name="Lee">{{cite journal|last=Naish|first=Lee|title=Partial disclosure of votes in STV elections|journal=Voting matters|volume=30|pages=9-13|year=2013|url=http://www.votingmatters.org.uk/ISSUE30/I30P2.pdf}}</ref>
=== Related
*[[SNTV|Single Non-Transferable Vote]]
* [[CPO-STV]]
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