Correlated Instant Borda Runoff: Difference between revisions

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Correlated Instant Borda Runoff (CIBR) is a [[preferential voting|preferential]] [[voting system]] for single-winner elections, devised by Ken Kuhlman in May 2005 in order to reduce [[Borda]]'s susceptability to [[clones]].
== Procedure ==
Candidates are scored according to the [[Borda count]]. The Borda loser of the [[candidate correlation|most-correlated]] pair of candidates is eliminated. The process is repeated until only one candidate remains.
== Example ==
The [[Borda]] scores for the four candidates are:
* Nashville: 194
* Chattanooga: 173
* Memphis: 126
* Knoxville: 107
If "correlation" is defined as [[third-order correlation]], then the most-correlated pair is Chattanooga and Knoxville. Knoxville has fewer Borda points and so is eliminated. After this elimination, the Borda scores for the remaining candidates are:
* Nashville: 126
* Chattanooga: 90
* Memphis: 84
and the correlations are:
* Nashville & Chattanooga: 100%
* Nashville & Memphis: 74%
* Chattanoogs & Memphis: 26%
The new most-correlated pair is Nashville and Chattanooga. Chattanooga is the Borda loser of this pair and is eliminated. The Borda scores of the remaining pair of candidates are:
* Nashville: 58
* Memphis: 42
Memphis is eliminated, and Nashville wins.
== Criteria Compliance ==
CIBR passes:
* [[summability criterion|third-order summability]]
It fails:
* [[Condorcet criterion]]
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