User:Cymru/Independence of correlated candidates criterion: Difference between revisions

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The '''Independence of CorrelatedEquivalent Candidates criterion''' was devised in 2005 by Thomas Smith. It was inspired by the inadequate definition of the [[Strategic nomination|independence of clones]] criterion which does not properly address rated voting systems and presumes that correlatedequivalent candidates are identical or very similar to each other.
CorrelatedEquivalent candidates are a group of candidates that are supportively ranked or rated in adjacent orpositions, where equal positionsranking is not allowed, onor everyequally castranked ballot.or rated, Thiswhere definitionequality excludesis candidatesallowed, whoon areevery differentiatedcast byballot. disapproval orThus, 0an ratingapproved fromand beinga correlateddisapproved withcandidate thosecan givennever supportivebe ranking"clones" oras ratingthey are not rated equivalently.
 
A voting method is said to be independent of correlatedequivalent candidates if the addition or removal of a correlatedequivalent candidate from a particular set of correlatedequivalent candidates in the tally, would only change the winner to another member of the set, if the original winner was a member of that set.
 
Methods that satisfy this criterion are [[approval voting], [[range voting]], [[Bucklin voting]], [[Schulze method]], and [[Instant-runoff voting]].
Independence of correlated candidates is a weakened form of the [[independence of irrelevant alternatives]] criterion.
 
Independence of correlatedequivalent candidates is a weakened form of the [[independence of irrelevant alternatives]] criterion.

Revision as of 23:16, 20 September 2005

The Independence of Equivalent Candidates criterion was devised in 2005 by Thomas Smith. It was inspired by the inadequate definition of the independence of clones criterion which does not properly address rated voting systems and presumes that equivalent candidates are identical or very similar to each other.

Equivalent candidates are a group of candidates that are supportively ranked in adjacent positions, where equal ranking is not allowed, or equally ranked or rated, where equality is allowed, on every cast ballot. Thus, an approved and a disapproved candidate can never be "clones" as they are not rated equivalently.

A voting method is said to be independent of equivalent candidates if the addition or removal of a equivalent candidate from a particular set of equivalent candidates in the tally, would only change the winner to another member of the set, if the original winner was a member of that set.

Methods that satisfy this criterion are [[approval voting], range voting, Bucklin voting, Schulze method, and Instant-runoff voting.

Independence of equivalent candidates is a weakened form of the independence of irrelevant alternatives criterion.