46 lines
2.0 KiB
Markdown
46 lines
2.0 KiB
Markdown
# Condorcet
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Condorcet is an election method that selects the candidate, if such a candidate exists, that would win a [majority vote](majority_voting.md) against all other candidates. Ballots may take the form of either a single [ranked choice](ranked_choice.md) vote or a sequence of runoffs.
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There is not always a "Condorcet winner," and various implementations provide differing methods of determining a winner in such cases.
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**Input:** preferential vote or runoffs
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**Output:** Condorcet winner or circular paradox
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## Background
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The Condorcet method takes its name from an early promoter, the 18th-century French mathematician Marie Jean Antoine Nicolas Caritat, who was the Marquis de Condorcet. The method itself was [first described by Ramon Llull](https://www.math.uni-augsburg.de/htdocs/emeriti/pukelsheim/2001a.html) in 1299. A version of it is used in Robert's Rules of Order, first published in 1876.
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Recently, it has attracted the interest of software developers and has been adopted by several prominent Free Software communities and Pirate Party groups.
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## Feedback loops
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### Sensitivities
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* Prevents some potential for gaming that is possible in other voting methods
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### Oversights
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* The complexity of the system may lead to confusion
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## Implementations
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### Communities
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* Free Software communities
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- [Debian Project](https://www.debian.org/vote/)
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- [Python Software Foundation voting process](https://www.python.org/dev/peps/pep-8001/)
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- Wikimedia Foundation
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* Pirate Party of Sweden uses it for primary elections
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### Tools
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* [Condorcet Internet Voting Service](https://civs.cs.cornell.edu/) at Cornell University
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## Further resources
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* "[Condorcet method](https://en.wikipedia.org/wiki/Condorcet_method)" at Wikipedia
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* Schulze, Markus. "[A new monotonic, clone-independent, reversal symmetric, and condorcet-consistent single-winner election method](https://link.springer.com/article/10.1007/s00355-010-0475-4)." _Social Choice and Welfare_ 36, no. 2 (February 2011).
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