On Fri, 17 Jan 2003, Forest Simmons wrote: ...
> > In fact, suppose that your favorite candidate is A, and that there are two > front runners B and C, of which your preferred is B, so that your sincere > preferences (restricted to these three candidates) look like A>B>C. > > What would be the worst that could happen if you voted your MCA ballot > sincerely (under the cumulative rules for preferred status and approval > rules for acceptable status)? > > There are realistically only two bad possibilities: > > (1) Candidate C wins with more than 50 percent of the favored status > votes. > > (2) No candidate wins in the "majority choice" round, but candidate C wins > in the approval round. > > In case (1) it wouldn't have helped to put B ahead of A on your ballot, > because only one candidate can have a 50 plus percent majority in the > cumulative stage, and (in the case under consideration) candidate C is > that candidate. > > In case (2) it wouldn't have helped to put B ahead of A on your ballot, > because in the second round, favored status and merely approved status are > not distinguished. > > So if this method does not satisfy the strong FBC, it is because of some > other much less likely scenario that we haven't considered here. > Actually, there is one other likely possibility associated with case (2): since nobody won in the first round, it is possible that compromise B would have won in the first round if you had voted him over favorite A. The fact that neither B nor C had actual majority first place support, and that B lost to C in the approval round make it very unlikely that B would have gotten a majority in the first round if you (and others like you) had betrayed favorite. Still, that possibility is there to haunt you. I still claim that this version of MCA comes closer to satisfying the strong FBC than most other (more complicated) methods, including IRV. Forest ---- For more information about this list (subscribe, unsubscribe, FAQ, etc), please see http://www.eskimo.com/~robla/em
