Defeat strength: Difference between revisions
Fixed definitions and added citation needed to pairwise opposition Plurality failure. MMPO fails Plurality, but to say that PO as such does needs more evidence. Added cn to Schulze being wv - would be good to get a ref from Markus.
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(Fixed definitions and added citation needed to pairwise opposition Plurality failure. MMPO fails Plurality, but to say that PO as such does needs more evidence. Added cn to Schulze being wv - would be good to get a ref from Markus.) |
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=== Standard ===
* '''winning votes (wv)''' =
** Example method: the [[Schulze method]] is usually taken to use winning votes.{{cn|date=May 2024}}
* '''margins''' = (
** Gives more strategic incentive than wv
* '''pairwise opposition''': Defeat strength = 100% - % of votes for L>W▼
** Example method: Tideman originally defined [[Ranked Pairs]] as a margins method.<ref name="Tideman2">{{Cite journal |last=Tideman |first=T. N. |date=1987-09-01 |title=Independence of clones as a criterion for voting rules |url=https://doi.org/10.1007/BF00433944 |journal=Social Choice and Welfare |language=en |volume=4 |issue=3 |pages=185–206 |doi=10.1007/BF00433944 |issn=1432-217X}}</ref>
** Violates [[plurality criterion]]▼
▲** Violates [[plurality criterion]].{{cn|date=May 2024}}
** Example method: [[MMPO]].
* '''Relative margins''': Defeat strength = margin ÷ (votes for W≠L)
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* (Pairwise) '''defeat''' <=> ''more voters expressed to prefer A over B than expressed to prefer B over A''
* '''Majority-strength defeat''' = ''pairwise defeat which has a wv-strength of more than half the no. of voters.'' Using only such defeats can reduce incentive to truncate by reducing the likelihood that additional preferences will harm earlier ones. Voters adding a preference can create a majority-strength win, but they can't reverse the direction of one.
== References ==
<references />
[[Category:Voting theory metrics]]
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