[EM] clones and FBC

Warren Smith wds at math.temple.edu
Sat Nov 19 09:36:56 PST 2005

I have added this comment to the FBC-survey to address Venzke's correction 
re clones:

But MDDA seems superior to MDDB because of its immunity to clones. That was assuming all X's clones are ranked co-equal to X on all ballots. But if voters can have slight preferences among the clones, then MDDA is not clone-immune and indeed every MDD-method is not (and nor is Simpson-Kramer min-max[pairwise opposition] nor ICA), because a majority-preference cycle can appear disqualifying every clone of the winner, including that winner. Similarly, ER-Bucklin is clone-immune with clones equality-ranked, but not with preferences among the clones, since cloning the winner can cause all winner-clones to be delayed in acquiring the necessary vote-majority, allowing somebody else to win sooner.

So there are two kinds of clone-immunity, a weaker and stronger kind...

More information about the Election-Methods mailing list