Condorcet method: Difference between revisions
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== Use of Condorcet voting ==▼
== Notes ==▼
Condorcet voting is not currently used in government elections. However, it is starting to receive support in some public organizations. Organizations which currently use some variant of the Condorcet method are:▼
Any voting method can be made a Condorcet method by simply adding a condition that a Condorcet winner will win if one exists before running the voting method. It is possible to further make a voting method [[Smith-efficient]] by taking various approaches, such as eliminating candidates one by one until there is a Condorcet winner (like in [[Benham's method]]) or eliminating all candidates not in the [[Smith set]] before running the voting method's procedure. It is common terminology for Condorcet methods that start by electing the Condorcet winner if there is one, but otherwise run some other voting method, to be named as "Condorcet//voting method". For example, [[Condorcet//Score]] is [[Score voting]] modified to elect a CW. The Condorcet methods that start by eliminating all candidates not in a given set of candidates and then
All Condorcet methods pass the [[
# The [http://www.spi-inc.org/ Software in the Public Interest (SPI)] project uses the [[Schulze method]].▼
# The [[W:Free State Project|Free State Project]] used a Condorcet method for choosing its target state▼
# The voting procedure for the uk.* hierarchy of Usenet▼
#[http://www.rsabey.pwp.blueyonder.co.uk/rpc/fscc/ Five-Second Crossword Competition]▼
Most Condorcet methods allow for equal-ranking. Because of this, it is possible to vote [[Approval voting]]-style. In fact, if all voters vote Approval-style, the Smith set will only have candidates who pairwise tie, rather than who have [[Condorcet cycle|Condorcet cycles]]. This mitigates one common utilitarian concern with Condorcet, that it might let a majority force its weak preference onto the minority, because voters with weak preferences may be willing to equally rank candidates in order to allow voters with stronger preferences to have the deciding vote. ▼
▲== Notes ==
▲All Condorcet methods pass the [[Mutual majority criterion|mutual majority criterion]] when there is a Condorcet winner. This is because the CW is guaranteed to be a member of any set of candidates that can pairwise beat all candidates not in the set, and the mutual majority set is such a set, because all candidates in it are ranked by a majority over all candidates not in the set. [[Smith-efficient]] Condorcet methods always pass the [[Mutual majority criterion|mutual majority criterion]].
One concern with Condorcet methods is that it is very difficult to do [[pairwise counting]] for elections with 10 of more candidates, since that is at least (0.5*10*((10-1)=9))=45 pairwise matchups to record the details of. Allowing write-in candidates makes things even more complex. One possible solution would be to have a primary beforehand using a voting method better than [[FPTP]] to pick 5 top candidates, and then only allow voters to rank those top 5. For all other candidates, they'd be able to approve or score each of them. The rated information could then be used to elect someone other than one of the top 5 when the non-top 5 candidates have significantly higher ratings, but otherwise only elect one of the top 5. The primary itself could be made slightly semi-proportional as well.
▲Most Condorcet methods allow for equal-ranking. Because of this, it is possible to vote [[Approval voting]]-style. In fact, if all voters vote Approval-style, the Smith set will only have candidates who pairwise tie, rather than who have [[Condorcet cycle|Condorcet cycles]].
▲== Use of Condorcet voting ==
▲It is common terminology for Condorcet methods that start by electing the Condorcet winner if there is one, but otherwise run some other voting method, to be named as "Condorcet//voting method". For example, [[Condorcet//Score]]. The Condorcet methods that start by eliminating all candidates not in a given set of candidates and then running some other voting method are named as "Given set//voting method" (sometimes with only one "/"). For example, [[Smith//IRV]] is [[IRV]] run on the [[Smith set]].
▲Condorcet voting is not currently used in government elections. However, it is starting to receive support in some public organizations. Organizations which currently use some variant of the Condorcet method are:
▲# The
▲One concern with Condorcet methods is that it is very difficult to do [[pairwise counting]] for elections with 10 of more candidates, since that is at least (0.5*10*((10-1)=9))=45 pairwise matchups to record the details of. Allowing write-in candidates makes things even more complex. One possible solution would be to have a primary beforehand using a voting method better than [[FPTP]] to pick 5 top candidates, and then only allow voters to rank those top 5. For all other candidates, they'd be able to approve or score each of them. The rated information could then be used to elect someone other than one of the top 5 when the non-top 5 candidates have significantly higher ratings, but otherwise only elect one of the top 5. The primary itself could be made slightly semi-proportional as well. {{fromwikipedia}}
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▲# The [[W:Free State Project|Free State Project]] used a Condorcet method for choosing its target state
▲# The voting procedure for the uk.* hierarchy of Usenet
▲# [http://www.rsabey.pwp.blueyonder.co.uk/rpc/fscc/ Five-Second Crossword Competition]
{{fromwikipedia}}
== External links ==
* [http://condorcet.ericgorr.net Condorcet Voting Calculator] by Eric Gorr ([[Ranked Pairs]], and [[Schulze]])
* [http://robla.net/1996/politics/condorcet.html Condorcet's Method] by Rob Lanphier
* [http://accuratedemocracy.com/ Accurate Democracy] by Rob Loring
* [http://fc.antioch.edu/~james_green-armytage/voting.htm Voting methods resource page] by James Green-Armytage
* [http://radicalcentrism.org/majority_voting.html Maximum Majority Voting] by Ernest Prabhakar
* [http://www.mcs.vuw.ac.nz/~ncj/comp303/schulze.pdf A New Monotonic and Clone-Independent Single-Winner Election Method] ([[Portable Document Format|PDF]]) by Markus Schulze ([http://www.citizensassembly.bc.ca/resources/submissions/csharman-10_0409201706-143.pdf mirror1], [http://lists.gnu.org/archive/html/demexp-dev/2003-09/pdflQW7IlpAfC.pdf mirror2]) (Schulze method)
* [http://www.OpenSTV.org/ OpenSTV] — Software for computing Condorcet methods and STV by Jeffrey O'Neill
* [http://www5.cs.cornell.edu/~andru/civs/ CIVS, a free web poll service using the Condorcet method] by Andrew Myers
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