View source for Correlated Instant Borda Runoff

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 ==

{{Tenn_voting_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]]


[[Category:Single-winner voting methods]][[Category:Ranked voting methods]]