Majority Choice Approval: Difference between revisions
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'''Majority Choice Approval''' ('''MCA''') is a class of rated voting systems which attempt to find majority support for some candidate. It is closely related to Bucklin Voting, which refers to ranked systems using similar rules. In fact, some people consider MCA a subclass of Bucklin, calling it [[ER-Bucklin]] (for Equal-Ratings-[allowed] Bucklin).
== How does it work? ==
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There is no preferred majority winner. Therefore approved votes are added. This moves Nashville and
Various strategy attempts are possible in this scenario, but all would likely fail. If the eastern and western halves of the state both strategically refused to approve each other, in an attempt by the eastern half to pick
== General strategy and notes ==
If the electorate knows which two candidates are frontrunners, and the pairwise champion is indeed among those two, the stable strategy is for everyone to approve or prefer exactly one of those two, and fill out the rest of the ballot honestly and as expressively as possible. (In the example above, that would mean an east/west split, with Nashville winning 68-32 approval over
However, this two-frontrunner strategy does not mean that MCA is subject to [[W:Duverger's law|Duverger's law]]. A pairwise champion who is not one of the perceived frontrunners still has a good chance of winning, especially if they have some strong supporters. This fact, in turn, will affect what "frontrunner" means; an extremist candidate with a strong but sharply-limited base of support - the kind of candidate who, using simple [[runoff voting]], makes it into a runoff with a strong showing of 35% but then gets creamed with only 37% in the runoff - will never be perceived as a frontrunner in the first place.
Thus, overall, many elections should be resolved without need for a resolution method, and so all MCA methods should give broadly similar results. However, if resolution is needed, a lack of majorities is, overall, more likely than multiple majorities. Since the design intent is to minimize these situations, the resolution method chosen should be one which tends to encourage extending approvals; that is, one which comes "close" to fulfilling the [[Later-no-harm criterion]], so that extending approval is unlikely to harm one's favorite candidate. From simple to complex, such methods are: MCA-S, MCA-IR, and MCA-AR.
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