First preference Copeland

From electowiki
Revision as of 11:02, 22 July 2022 by Kristomun (talk | contribs) (Added and linkified names, as well as a link to the WDS proof that FPC is not cloneproof.)

First preference Copeland is a variant on the Copeland method. It was devised by Forest Simmons in 2006. [1] The name is due to Kristofer Munsterhjelm.[2]

In first preference Copeland, each candidate is assigned a penalty: the sum of first preferences of the candidates that beat the candidate pairwise. The candidate with the least penalty wins.

First preference Copeland passes Smith because supposing otherwise, that some candidate Y not in the Smith set wins; then for a candidate X in the Smith set, Y is beaten by every candidate X is beaten by, and some more. Thus Y's penalty must be higher than X's, so Y couldn't have been the winner.

However, FPC fails both independence of clone alternatives[3] and the monotonicity criterion.

This page is a stub - please add to it.

References

  1. Simmons, F. (2006-12-30). "Clone proofing Copeland". Election-methods mailing list archives.
  2. Munsterhjelm, K. (2008-07-13). "[Election-Methods] A Better Version of IRV?". Election-methods mailing list archives.
  3. Smith, W. (2006-12-31). "Wait a minute - Simmons' "cloneproof" method is not really cloneproof!". RangeVoting Yahoo list mirror.