WV vs margins: All along, I've been referring people to the electionmethods website for the defensive strategy criteria that justify my method arguments. I might as well restate it here: http://www.electionmethods.org Two people have pointed out that, though margins has strategy problems that wv doesn't have, it's also true that wv has possible stratgegy temptations that margins doesn't have. This isn't surprising. Gibbard & Satterthwaite demonstrated that , with any method, there can be situations in which someone can gain from strategy. So it's a matter of choosing which strategy problems you want, and which you most want to avoid. For instance, comparing wv's strategy situation with that of margins, which causes a lesser-of-2-evils problem? Which causes a gross majority rule violation? Answer: Margins. Additionally, wv's strategic temptation to sincerely rank 2nd choice equal to favorite only brings benefit in a natural circular tie. Margins' strategy problems can result in truncation stealing the election from a sincere CW. When, in wv, you incerely rank unequally your equally-preferred lower choices, you're falsifying preferences. But falsifying a preference in that way is like half of an order-reversal. Both wv & margins have order-reversal as an offensive strategy. Rob wanted a method that deters order-reversal better than Margins does. Ok, the wv methods do. With the wv methods, simple defensive truncation is all it takes to make offensive order-reversal backfire badly. If offensive order-reversal ever began to be used, people would soon know about it, and if some were sophisticated enough to use it, others would be sophisticated enough to deter it. It would be impossible to organize a jurisdiction-wide order-reversal without others hearing about it. And using counterstrategy. Offensive order-reversers would usually regret it very much. After a few tries, they'd quit using it. I claim that offensive order-reversal won't be used on a scale sufficient to change the election result. Thwarting order-reversal in Margins requires order-reversal. Thwarting truncation requires at least truncation. With wv, truncation thwarts offensive order-reversal, and no one has to do anything to thwart offensive truncation, because it can't steal the election from a sincere CW or a member of the sincere Smith set, under the plausible conditions described in SFC & GSFC. The bottom-line of these strategy problems is: What kind of strategy problems do they cause for you if someone else truncates or order-reverses? Because truncation & order-reversal are the only things that can threaten a CW in pairwise methods. Ok, truncation causes no problem in wv, but it causes a problem in Margins. In Margins, but not in wv, offensive order-reversal requires order-reversal as a defense. The strategy _needs_ that Margins imposes are the problem. The unimportant strategy temptations that wv has aren't a problem. In the poll whose balloting commences tomorrow, if you designate a margins method, and if some people truncate, as I and many others did in the previous poll, then there's a good chance that your Margins method will, as a result, miss the sincere CW and place your final Approval cutoff point lower than it should, giving the election away to something that you like less than that sincere CW. Likewise, Margins can miss by giving one of your final Approval votes to something outside the sincere Smith set, and less liked by you than some member of that set, giving away the election to that less-liked alternative. Maybe you like Margins better for aesthetic reasons, because it looks more symmetrical, but I suggest that, when you designate a method for Voter's Choice, you consider which method is going to miss and give away the election. And then ask yourself if you'd want, for public elections, a method that you don't want to designate in Voter's Choice. Mike Ossipoff _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com