At 02:37 PM 2/8/2007, Warren Smith wrote: >My computer sims showed that range voting does so more often than >Condorcet methods >based on rank-order ballots. Paradoxical seeming. But true. > >Since this is an experimental fact, it is indisputable. Computer simulations. >The page discussing this is > http://www.rangevoting.org/StratHonMix.html >(Also, same results happen for other mixes than 50-50...) > >CAVEAT: I should note that IEVS presently is only doing rank order >ballots, I.e. >equalities in rankings were forbidden in these sims.
Warren has a tendency to hyperbole, but his point should not be missed. Unless and until it is confirmed, his work must be taken with some salt, but it nevertheless does show what he claims. It appears that some are criticizing it without being familiar with it, perhaps on the basis that they find the results unpalatable. But the *huge* problem with a great deal of EM evaluation is that it is so often based on election criteria, presumed to be desirable, rather than on some kind of measurement of success in *results*. Warren's work is not based on any specific assumption of how voters vote. Rather, it applies various stated assumptions, showing the effect of sincere voting, strategic voting, and mixes, to a large number of sample elections. As he noted, the result that Range is more successful at picking the sincere Condorcet winner than Condorcet methods is, to say the least, counterintuitive. The problem, of course, is strategic voting, where voters do not express their sincere preferences, fearing that if they do, the result will be less satisfactory than if they shift them. One of the characteristics of Range is that there is never an incentive to reverse preferences. Strategic or insincere voting in Range is limited to equating candidates at the extremes when, in fact, you do have a preference between them. Warren calls this partially sincere. I've called it "magnification;' the gain on an amplifier has been increased until the output pegs the meter. The contrast on an image has been increased until some detail is lost in total black or white. It isn't insincere in the same way as preference reversal is. Warren likes Range with unlimited resolution because it becomes possible to express fine differences in preference while retaining effectively full voting power. (It is true that if you downrate B from A by a thousandth of a point, you could cause B to lose to C. But the possibility becomes vanishingly small. One way to look at a range vote of 0.999 -- compared to 1.0 -- is that it is one-thousandth of a vote different. Warren's results though, were with limited Range resolution. I think he has done work with Approval, with Range 10 and with Range 100. But the Condorcet Criterion itself is severely limited. Once one realizes how it is quite easy for the best candidate (from a social utility point of view, which is really the only criterion that has been suggested that actually measures election performance) to not be a Condorcet winner, the Condorcet Criterion can be seen as less than ideal. Generally, the neglect of preference strength is the elephant in the living room of ranked methods. It is trivial to give simple examples that show, beyond doubt, how Condorcet can choose the wrong winner. What is really odd to me is that it seems to have taken so long to recognize this. Does anyone know when this began to show up in the literature? Once a method allows preference strength to enter into consideration in determining the winner, the method *must* fail Condorcet. (With the limited exception that if preference strength is only used to choose between members of a Condorcet cycle, there need be no Condorcet violation.) Likewise the Majority Criterion, as generally stated, will not be satisfied in all elections. However, quite arguably (I'd say *clearly*), Range fails Condorcet in order to choose a better winner. This is absolutely clear if all voters vote sincerely and accurately. It is muddier in the presence of strategic voting (the definition of which becomes somewhat problematic with Range), but Warren's results show what some of us anticipated: strategic voting doesn't do nearly as much harm as some Range critics have claimed it would. ---- election-methods mailing list - see http://electorama.com/em for list info
