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{{mergedisputed}} [[Condorcet criterion]]
 
Any election method conforming to the [[Condorcet criterion]] is known as a '''Condorcet method'''. The name comes from a deviser, the [[18th century]] [[mathematician]] and [[philosopher]] [[Marquis de Condorcet]], although the method was previously devised by [[Ramon Llull]] in the [[13th century]].
 
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Examples of Condorcet methods include:
* '''[[Black]]''' chooses the Condorcet winner when it exists and otherwise the [[Borda count|Borda winner]]. It is named after [[Duncan Black]].
* '''[[Smith/IRV]]''' is [[instant-runoff voting]] with the candidates restricted to the Smith set.
* '''[[Copeland's method|Copeland]]''' selects the candidate that wins the most pairwise matchups. Note that if there is no Condorcet winner, Copeland will often still result in a tie.
* '''[[Minimax''' (also called '''Simpson''') chooses the candidate whose worst pair wise defeat is less bad than that of all other candidates.<sup>1</sup>
* '''Smith/Minimax''' restricts the Minimax algorithm to the Smith set.<sup>1</sup>
* '''[[Ranked Pairs]]''' (RP) or '''Tideman''' (named after [[Nicolaus Tideman]]) with variations such as '''[[Maximize Affirmed Majorities]]''' (MAM) and '''[[Maximum Majority Voting]]''' (MMV)<sup>1</sup>
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In this election, Nashville is the Condorcet winner and thus the winner under all possible Condorcet methods. Notice how [[first-past-the-post]] and [[instant-runoff voting]] would have respectively selected Memphis and Knoxville here, while compared to either of them, most people would have preferred Nashville.
 
== Condorcet compared to Instant Runoff and First-past-the-post ==
 
Only an explicit Condorcet based method will comply with the [[Condorcet criterion]] so that if there is a Condorcet winner (a candidate who, when compared in turn with each of the other candidates, is preferred over the other candidate) then that individual is selected. So there are circumstances, as in the example above, when both instant-runoff voting and plurality voting will fail to pick the Condorcet winner.
 
Proponents of the Condorcet criterion see that as the principal issue in selecting an electoral system. They see the Condorcet criterion as a natural extension of [[Majoritarianism|majority rule]].
 
Condorcet methods tend to encourage the selection of centrist candidates who may have a low level of "first choice" support, but a high level of "middle rank" support, especially if the [[voting system]] encourages all candidates to adjust their position to appeal to the [[median]] voter. To take another example, consider the following vote count of preferences with three candidates {A,B,C}:
 
<blockquote><table>
<tr><td align=right>499:</td><td align=left>A,B,C</td></tr>
<tr><td align=right>3:</td><td align=left>B,C,A</td></tr>
<tr><td align=right>498:</td><td align=left>C,B,A</td></tr>
</table></blockquote>
 
In this case, B is preferred to A by 501 votes to 499, and B is
preferred to C by 502 to 498, hence B is preferred to both A and C. So
according to the Condorcet criterion, B should win. By contrast, according to the rules of IRV, B is ranked first by the fewest voters and is eliminated, and C wins with the transferred votes from B; in plurality voting A wins with the most first choices.
 
Proponents of most Condorcet voting systems also claim a technical advantage in that since the ballot totals in each pairwise race are used to determine the winner, the results can be tallied in a distributed fashion - i.e., at the precinct level. Proponents of instant-runoff voting respond that fewer counts of votes are needed with their system, since only transferred votes need more than one observation; however, these counts must be done either with all ballots gathered centrally or with simultaneous counts and transfers at each precinct, which may be hard for large elections. Proponents of plurality voting state that their system is simpler than any other and more easily understood.
 
All three systems are susceptible to [[tactical voting]] and [[strategic nomination]]s.
 
== Use of Condorcet voting ==
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# The voting procedure for the [[United Kingdom|uk]].* hierarchy of [[Usenet]]
#[http://www.rsabey.pwp.blueyonder.co.uk/rpc/fscc/ Five-Second Crossword Competition]
 
==See also==
*[[List of democracy and elections-related topics]]
 
== External resources ==
* [http://www-gap.dcs.st-and.ac.uk/~history/HistTopics/Voting.html The history of voting]
* [http://electorama.com/em A mailing list containing technical discussions about election methods]
* [http://condorcet.ericgorr.net Condorcet Voting Calculator]
* [http://www.eskimo.com/~robla/politics/condorcet.html Condorcet's Method]
* [http://electionmethods.org/ electionmethods.org]
* [http://condorcet.org/rp Ranked Pairs]
* [http://accuratedemocracy.com/ Accurate Democracy]
* [http://www.alumni.caltech.edu/~seppley The Maximize Affirmed Majorities voting procedure (MAM)]
* [http://radicalcentrism.org/majority_voting.html Maximum Majority Voting]
* [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])
* [http://cec.wustl.edu/~rhl1/rbvote/desc.html Descriptions of ranked-ballot voting methods]
* [http://fc.antioch.edu/~jarmyta@antioch-college.edu/voting.htm Voting methods resource page]
* [http://stv.sourceforge.net/ pSTV -- Software for computing Condorcet methods and STV]
* [http://www5.cs.cornell.edu/~andru/civs/ CIVS -- Condorcet Internet Voting Service]
 
[[Category:Voting systems]]
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