Favorite betrayal criterion: Difference between revisions
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{{wikipedia|Draft:Favorite betrayal criterion}}
The '''favorite betrayal criterion''' (sometimes called '''sincere favorite criterion<ref name=":0">{{cite web|url=https://arxiv.org/abs/2301.12075|title=An Examination of Ranked Choice Voting in the United States, 2004-2022|last=Graham-Squire|first=Adam|last2=McCune|first2=David|date=2023-01-28|website=arXiv.org|access-date=2023-10-25}}</ref>''') is a [[voting system criterion]] which requires that "voters should have no incentive to vote someone else over their favorite".<ref>{{Cite web|url=https://rangevoting.org/FBCsurvey.html|title=Survey of FBC (Favorite-Betrayal Criterion)|last=Ossipoff|first=Mike|last2=Smith|first2=Warren D.|date=Jan 2007|website=Center for Range Voting|url-status=live|archive-url=|archive-date=|access-date=2020-04-08}}</ref> Voting systems failing the criterion are vulnerable to a kind of strategy called '''decapitation''', i.e. removing the top ("head") of a ballot.<ref name=":0" />
It is passed by [[Approval voting]], [[Range voting]], and [[Majority Judgment]]. All these are examples of [[cardinal voting systems]], though some voters may be reluctant to have a compromise candidate tied with their favorite candidate on their respective ballots.
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On the other hand, most [[Ranked voting systems|ordinal voting systems]] do not pass this criterion. For instance, [[Borda Count]], [[Copeland's method]], [[Instant runoff voting]] (IRV, known in the UK as the Alternative Vote), [[Kemeny-Young method|Kemeny-Young]], [[Minimax Condorcet]], [[Ranked Pairs]], and [[Schulze method|Schulze]] all fail this criterion. A few ordinal methods, like [[weighted positional method|Antiplurality]], pass it. Some [[Condorcet methods]] pass it when combined with the [[tied at the top]] rule, though this means they may not be Condorcet-efficient when some voters equally rank multiple candidates.
It is also failed by [[
== Definition ==
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