Blake posted an example in which someone can gain by truncation. No nonprobabilistic method is entirely strategy-free, but we can reduce the extremeness of defensive strategy need, or the range of conditions in which drastic defensive strategies are needed. The defensive strategy criteria show some of the degree of strategy- freedom that can be gained by the better methods. For instance, defensive order-reversal is a commonly-needed defensive strategy in Plurality, IRV, and the margins methods, to an easily avoidable degree. And those methods have situations in which every Nash equilibrium is one in which people use defensive order-reversal.
An outcome that isn't a Nash equilibrium is unstable in a really obvious way. In Plurality, IRV, and the margins methods, sometimes the only vote configurations that aren't unstable in that way are ones in which defensive order-reversal is used. Maybe margins advocates don't care about strategy problems. They're in good company: Advocates of Plurality, IRV, and Borda don't either. But margins advocates need to understand that their standards don't have some sort of absolute betterness. Let them sell their methods to people who are as forgiving about strategy problems as they are. I don't have any argument with them. Their method is great by their standards. Blake said: I think it is possible to penalize partial rankings more severely than winning-votes does. I reply: I wasn't aware that wv penalizes partial rankings. But we've been all over that issue, and there'd be no point in arguing about it more. Mike Ossipoff _________________________________________________________________ Join the world�s largest e-mail service with MSN Hotmail. http://www.hotmail.com ---- For more information about this list (subscribe, unsubscribe, FAQ, etc), please see http://www.eskimo.com/~robla/em
