Dear participants, I have uploaded the paper "Monotonicity and Single-Seat Election Rules" (Voting Matters, issue 6, page 9-14, May 1996) by Douglas R. Woodall: http://groups.yahoo.com/group/election-methods-list/files/wood1996.pdf
In this paper, Woodall introduces the so-called "plurality criterion": > Plurality: If some candidate x has strictly fewer votes > in total than some other candidate y has first-preference > votes, then x should not have greater probability than y > of being elected. Woodall writes: > Election 3 > ab 11 > b 7 > c 12 > > (...) > > It seems that most of the Condorcet-based properties > discussed in the Social Choice literature would in fact > elect a in Election 3, and so violate plurality (whereas > AV elects c and DAC elects b). How seriously one regards > the failure of plurality depends on how one interprets > truncated preference listings, and that in turn may > depend on the rubric on the ballot paper. If the 12 c > voters are merely expressing indifference between a and b > and not hostility to them, and so can be treated in > exactly the same way as if half of them voted cab and half > voted cba, then the violation is not too serious. But if, > by plumping for c, these voters are not just saying that > they prefer c to a, but that they want c and definitely > do not want a (or b), and if the seven b voters also > definitely do not want a (or c), then it is clear that c > has more support than a and so a should not be elected. The beat path method and the ranked pairs method satisfy plurality only when the strength of a pairwise defeat is measured by the absolute number of votes for the winner of this pairwise defeat, but not when the strength of a pairwise defeat is measured by its margin. Markus Schulze ---- Election-methods mailing list - see http://electorama.com/em for list info
