Gov/en/Portal:Voting/Methods: Difference between revisions

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{{KidsIntro|~~There~~ are many ways to count votes. Sometimes the biggest pile of hands wins. Sometimes you rank your favorites, like first, second and third place. This page explains the main ways of voting, with a small example, so you can see why the counting method can change who wins.}}

{{KidsIntro|Most decisions do not need a vote at all: people just try things, undo mistakes and talk. But when a big question really needs a vote, there are many ways to count votes. Sometimes the biggest pile of hands wins. Sometimes you rank your favorites, like first, second and third place. This page explains the main ways of voting, with a small example, so you can see why the counting method can change who wins.}}

{{ExpertIntro|Survey of the voting methods WikiDeal is studying: simple majority, approval voting, ranked methods (Borda, instant-runoff), Condorcet methods with the Schulze completion, and single transferable vote for multi-seat elections. A worked 9-voter example shows a Condorcet winner losing under plurality. Each method is assessed against known criteria (clone independence, monotonicity) and known limits (Condorcet paradox, Arrow's impossibility theorem, strategic voting). The mapping of methods to decision types is a first hypothesis, consistent with Wikimedia and Debian practice.}}

{{ExpertIntro|None of these methods is meant for everyday decisions: formal voting, and Condorcet voting in particular, is reserved for complex or contested questions that need a clear, settled outcome, after lighter tools (direct action, revert, discussion) have been tried. Survey of the voting methods WikiDeal is studying: simple majority, approval voting, ranked methods (Borda, instant-runoff), Condorcet methods with the Schulze completion, and single transferable vote for multi-seat elections. A worked 9-voter example shows a Condorcet winner losing under plurality. Each method is assessed against known criteria (clone independence, monotonicity) and known limits (Condorcet paradox, Arrow's impossibility theorem, strategic voting). The mapping of methods to decision types is a first hypothesis, consistent with Wikimedia and Debian practice.}}

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= 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:Voting/Rules|Voting rules]] page; evidence and sources are on the [[Gov/en/Portal:Voting/Research|research page]].''

''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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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 happens in real elections (the Wikimedia Board election of 2008 contained such a cycle among mid-ranked candidates, see the [[Gov/en/Portal:Voting/Research|research 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 reserves it for complex multi-option decisions.

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 reserves it for complex multi-option decisions. 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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== 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]]):

{| class="wikitable"