[EMAIL PROTECTED] wrote: > A later place YES vote might be deemed conditional -- i.e. so as NOT to > injure an earlier place YES vote that is not paired equally. > > Example- > > (* Yes conditional vote) > > 2 A B* > 24 A B > 24 B A > 49 C
A similar system could be obtained by modifying IRV to allow voting of tied preferences. The above ballots could then be cast as: 2 A > B > C 24 A=B > C 24 B=A > C 49 C > A=B In each case, the conditional B voters are expressing their desire for their vote for B to count only if A does not win. Counting is like "conventional" IRV, except that the elimination doesn't stop when one candidate gets more than 50% of the ballots; it must continue until all candidates but one are eliminated. That is because, with tied preferences, a 50%+1 quota is not sufficient; a block of voters might have their votes transferred to a tied preference on the next round. For three candidates, I think this IRV variant is equivalent to Demo's idea, but not for four or more. The ranking in IRV is really a statement of multi-level conditionals, while Demo's method is restricted to one level of conditional ("If A loses, then make mine a B vote"). > The above is why simple Approval is defective -- i.e. it does not rank the > choices. What Demo sees as a defect, I see as a reasonable tradeoff. When methods try to achieve more expressivity than Approval, it always seems to be at the cost of bringing in worse defects, such as nonmonotonicity/inconsistency. I haven't looked into how this method, or the IRV variant, will do along those lines, though I suspect they will fail as IRV does. Also, as in IRV, we would be dealing in manufactured majorities. One thing that is obtained in the trade, besides greater expressivity, is a simplification of strategy. For example, in a replay of Gore v. Bush v. Nader, a Green voter (whose preferences are probably "Nader >> Gore > Bush") could vote "Nader > Gore > Bush" in the modified IRV (and have his/her votes treated just as they would be in conventional IRV), or "Nader Gore*" in Demo's scheme, which would receive the same treatment. There's no agonizing over whether to vote Nader+Gore or just Nader in ordinary Approval. That doesn't mean I like this method better than ordinary Approval -- it needs more study. One more potential advantage, from the standpoint of EM politics (or polemics?), is that the IRV folks would be free to always vote an IRV-style ballot, and the Approval folks would be free to always vote an Approval-style ballot. Unfortunately, there's no pairwise treatment, so the Condorcet folks are left out. And to echo Mike O., the IRV folks never seem to be willing to accept a compromise method anyway. Just based on gut feelings, I think that, for four or more candidates, Demo's idea is better than the modified IRV. Since the latter attempts to achieve a high level of expressivity, I suspect it will fail monotonicity and consistency more frequently and/or with worse consequences than the former method, particularly when the number of candidates is large. I think either method would be better than conventional IRV. -- Richard