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
== How does it work? ==
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* MCA-R: Runoff - Two "finalists" are chosen by one or two methods, such as one of the methods above or a equality-allowed Condorcet method over the given ballots. The finalists are then measured against each other using one of the following methods:
** MCA-IR: Instant runoff (Condorcet-style, using ballots): Ballots are recounted for whichever one of the finalists they rate higher. Ballots which rate both candidates at the same level are counted for neither.
** MCA-AR: Actual runoff: Voters return to the polls to choose one of the finalists. This has the advantage that one candidate is guaranteed to receive the absolute majority of the valid votes in the last round of voting of the system as a whole.
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* MCA-AR satisfies the [[Guaranteed majority criterion]], a criterion which can only be satisfied by a multi-round (runoff-based) method.
Thus, the MCA method which satisfies the most criteria is MCA-AR, using [[Schulze]] over the ballots to select one finalist and MCA-P to select the other. Also notable are MCA-M and MCA-P, which, as ''rated'' methods (and thus ones which fail Arrow's ''ranking''-based [[
== An example ==
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== Notes ==
MCA ballots can be modified to do [[Smith//Approval]] with the use of an [[approval threshold]]. Limiting the number of allowed rankings in Smith//Approval makes it closer in design to [[Approval voting]] than to most [[Condorcet method]]<nowiki/>s.
[[Category:Single-winner voting methods]]
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