Gov/en/Portal:Voting/Methods: Difference between revisions
Create voting methods page (draft): majority, approval, ranked, Condorcet/Schulze with worked example, STV, Arrow/Gibbard-Satterthwaite limits |
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{{KidsIntro| | {{KidsIntro|Most decisions need no vote: people try things, undo mistakes and talk. But when a big question needs a vote, there are many ways to count. Sometimes the biggest pile of hands wins; sometimes you rank favourites.}} | ||
{{ExpertIntro| | {{ExpertIntro|Formal voting is proposed only for high-stakes questions, after lighter tools (direct action, revert, discussion). Condorcet is considered relevant for complex, clearly contested cases. This survey covers the methods WikiDeal is studying: simple majority, approval, ranked methods, Condorcet with Schulze, and STV for multi-seat elections. The mapping of methods to decision types is a first hypothesis.}} | ||
__TOC__ | __TOC__ | ||
= Voting methods under study = | = Voting methods under study = | ||
''Status: first hypothesis (draft). WikiDeal has not adopted any voting method yet. This page documents the options being explored. Rules of procedure are on the [[Gov/en/Portal: | ''Status: first hypothesis (draft). WikiDeal has not adopted any voting method yet. This page documents the options being explored. When to vote at all is treated on the [[Gov/en/Portal:Voting/Main#ladder-of-tools|portal main page]]: most decisions are intended to be settled by lighter tools (direct action, revert, discussion), and a formal vote is a last resort. Rules of procedure are on the [[Gov/en/Portal:Voting/Rules|Voting rules]] page; evidence and sources are on the [[Gov/en/Portal:Voting/Research|research page]].'' | ||
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=== The Condorcet paradox and the Schulze completion === | === The Condorcet paradox and the Schulze completion === | ||
Sometimes there is no Condorcet winner: A can beat B, B beat C, and C beat A, like rock-paper-scissors. This is the [https://en.wikipedia.org/wiki/Condorcet_paradox Condorcet paradox], and it | Sometimes there is no Condorcet winner: A can beat B, B beat C, and C beat A, like rock-paper-scissors. This is the [https://en.wikipedia.org/wiki/Condorcet_paradox Condorcet paradox], and it can be observed in real ballot data: the published pairwise table of the 2008 Wikimedia Board election shows such a circle among three mid-ranked candidates (the exact figures are on the [[Gov/en/Portal:Voting/Research#wikimedia-experience|research page]] and the [[Gov/en/Portal:Voting/Condorcet-History|history and results page]]). | ||
The [https://en.wikipedia.org/wiki/Schulze_method Schulze method] resolves these cycles by comparing chains of victories (beatpaths): a chain is only as strong as its weakest link, and the option with the strongest chains wins. The Schulze method always elects the Condorcet winner when one exists, satisfies [https://en.wikipedia.org/wiki/Monotonicity_criterion monotonicity] and [https://en.wikipedia.org/wiki/Independence_of_clones_criterion independence of clones] (adding a similar option does not change the outcome), and is used by free software communities such as [https://en.wikipedia.org/wiki/Debian Debian]. This combination of properties is why the initial hypothesis | The [https://en.wikipedia.org/wiki/Schulze_method Schulze method] resolves these cycles by comparing chains of victories (beatpaths): a chain is only as strong as its weakest link, and the option with the strongest chains wins. The Schulze method always elects the Condorcet winner when one exists, satisfies [https://en.wikipedia.org/wiki/Monotonicity_criterion monotonicity] and [https://en.wikipedia.org/wiki/Independence_of_clones_criterion independence of clones] (adding a similar option does not change the outcome), and is used by free software communities such as [https://en.wikipedia.org/wiki/Debian Debian]. This combination of properties is why the initial hypothesis considers it relevant where a decision is complex and multi-option, and where the need to vote at all is clearly and widely perceived. Even then, a Schulze ballot is intended as a complement to the simpler tools, not a replacement: a contribution that can simply be reverted needs no vote, and a disagreement that discussion can settle needs none either. | ||
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* The [https://en.wikipedia.org/wiki/Gibbard%E2%80%93Satterthwaite_theorem Gibbard-Satterthwaite theorem] shows that every reasonable voting method can, in some situations, be manipulated by strategic voting. | * The [https://en.wikipedia.org/wiki/Gibbard%E2%80%93Satterthwaite_theorem Gibbard-Satterthwaite theorem] shows that every reasonable voting method can, in some situations, be manipulated by strategic voting. | ||
The practical conclusion is not that voting is pointless, but that methods must be chosen for the properties that matter most in each context, and that the choice of method is itself a governance decision. This is the basis of the principle stated on the [[Gov/en/Portal: | The practical conclusion is not that voting is pointless, but that methods must be chosen for the properties that matter most in each context, and that the choice of method is itself a governance decision. This is the basis of the principle stated on the [[Gov/en/Portal:Voting/Main|portal main page]]: match the method to the complexity of the decision. | ||
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== Which method for which decision == | == Which method for which decision == | ||
First hypothesis, to be validated: | First hypothesis, to be validated. This table applies only once a decision actually needs a formal vote; most decisions are intended to be settled earlier by direct action, revert and discussion (see the [[Gov/en/Portal:Voting/Main#ladder-of-tools|ladder of decision tools]]): | ||
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'''See also:''' [[Gov/en/Portal: | '''See also:''' [[Gov/en/Portal:Voting/Main|Voting at WikiDeal]] · [[Gov/en/Portal:Voting/Rules|Voting rules]] · [[Gov/en/Portal:Voting/Research|Voting research and experience]] · [[Gov/en/Portal:Voting/Condorcet-History|Condorcet history and results]] · [[Gov/en/Portal:Meta/Licensing-and-Credits|Licensing and credits]] | ||
[[Category:Migration June 2026]] | [[Category:Migration June 2026]] | ||
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