Hi Gervase, Some quick replies follow... >If you want something a bit more strategic resistant, Reynaud(Margins) >might be a good step up. I was thinking about this recently in relation >to the recent Approval 'Elimination' Condorcet thread and the Reynaud >thread. Chris Benham mentioned it in passing in the recent Reynaud >thread. > >If I got it right, the method can be summarised as "While there is no >Condorcet Winner, eliminate the candidate with the worst MinMax(Margins) >'score'".
Raynaud successively eliminates candidates with the strongest defeat against them. >I don't know whether this method is monotonic or not. I don't think it is. > >I get the feeling that Reynaud(Margins) is going to be the best you're >going to get with regards to a reasonable strategic resistant Margins >Pairwise method. I don't think that Raynaud is especially strategy resistant, whether with margins or winning votes. I'll repeat what I told Chris: Assume that the three sincere defeats are A>B A>C and B>C. In Raynaud, supporters of B need to make a fake C>A defeat which is the strongest of the three. (If order of defeat strengths is CA > AB?BC... B wins.) In defeat dropping methods, supporters of B need to make a fake C>A defeat so that the A>B defeat is the weakest of the three. (If order of defeat strengths is CA?BC > AB ... B wins.) So, which of these strategies is usually harder to pull off? Depends on the situation, right? In my little 46-44-10 example, then the Raynaud strategy would be harder, because the one and only possible "C" candidate does so poorly in sincere pairwise comparisons, and so some of the B>A>C voters would have to vote B=C>A to pull it off. However, I'd expect that in most serious multicandidate scenarios there would be at least one available "C" candidate such that B voters could make a fake C>A defeat that was bigger than the other two... And I'm starting to imagine the messy complications... Defeat dropping methods at least have the constraint that the A>B defeat needs to be weaker than the B>C defeat to begin with. No, I'm guessing that using Raynaud won't help too much on the strategy front... ... Anyway, if strategy is an issue, I wouldn't suggest a margins method at all. If strategy isn't an issue, then we're in la-la-land anyway, so it doesn't matter too much what voting method we use. my best, James ---- Election-methods mailing list - see http://electorama.com/em for list info