James, I've given some more thought to coming up with a criterion that distinguishes methods that use IRV as the most decisive stage (like Woodall's CNTT,AV aka Smith,IRV and CDTT,IRV), as being more resistant to Burying than Condorcet methods like the defeat-droppers, Raynaud (all versions) and SCRIRVE.
"If x is the CW (and wins), and on more than 1/3 of the ballots ranked above y and z; and afterwards on some of the ballots that rank y above x and x not below z, z's ranking relative to x is raised while keeping y ranked above them both, then if there is a new winner it cannot be y." This could be called the "Weak Burial Resistance" criterion, and of course is highly reminiscent of your excellent in-defence-of-IRV "Dominant Mutual Third" criterion. On Sun.Apr.10, you wrote a similar idea: "In IRV, if candidate X is the sincere Condorcet winner, and more than 1/3 of the voters rank X in first place, then I think that no strategic manipulation will be possible, in that no set of voters can gain mutual advantage by changing the winner to someone else. (You can probably generalize this from one candidate to a set of candidates, which I earlier defined as a "dominant mutual third" set.) I don't think that many pairwise methods share this property. So that would be a new problem,right? A sincere Condorcet winner with more than 1/3 of the first choice vote would no longer be totally safe from strategic manipulation." Chris Benham Find local movie times and trailers on Yahoo! Movies. http://au.movies.yahoo.com ---- Election-methods mailing list - see http://electorama.com/em for list info
