Correlated Instant Borda Runoff

Correlated Instant Borda Runoff (CIBR) is a 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 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:


 * third-order summability

It fails:


 * Condorcet criterion