2011/11/3 David L Wetzell <[email protected]> > > On Thu, Nov 3, 2011 at 9:14 AM, Kristofer Munsterhjelm < > [email protected]> wrote: > >> David L Wetzell wrote: >> >> And I don't think the Condorcet criterion is /that important/, as I >>> think in political elections, our options are inherently fuzzy options and >>> so all of our rankings are prone to be ad hoc. >>> >> >> If opinions are fuzzy, that means that the voters' true distribution >> within political space would differ somewhat from the distribution you >> would infer by looking at the votes alone. >> > > it could also mean that political spaces are at best somewhat useful > constructs and that the "true" distribution is something that's constantly > being manipulated, not taken as given. This understanding makes me tend > to be more middle-brow than most people on this list. > >> >> KM:In terms of the 2D Yee diagrams, this means that if the voters are >> centered on a certain pixel, their votes might behave as if it was centered >> on one of the neighboring pixels (since each pixel in a 2D Yee diagram >> gives who would win if the population were normally distributed around that >> point in political space and preferred candidates closer to them). So in a >> Condorcet method, this might sometimes lead to the wrong candidate being >> elected. It would do so in the case where the true distribution is on one >> side of the divider between two Voronoi cells, and the distribution >> inferred from the votes alone is at the other side. >> > dlw:Yup, getting the condorcet winner all of the time isn't the slam-dunk > it's purported to be. > >> >> KM:However, fuzzy opinions can cause greater problems with IRV. Because >> IRV is sensitive to the order of eliminations, it doesn't just have the >> clean cell transitions of Condorcet; it can also have disconnected regions >> near the edges or in the middle of one of the regions. In essence, these >> are the same as the "island of other candidates" artifacts, but in two >> dimensions rather than one. >> > > dlw: I'm afraid you lost me there. > >> >> KM:It may be the case that voters are not centrally distributed in >> political opinion-space, but I think the observation can be generalized. If >> I'm right, why put up with a method that, by sensitivity to the elimination >> order, amplifies the fuzziness of the votes? >> > > dlw: Well, 1. IRV3 doesn't let folks rank all of the options and so it > hopefully has more quality control on which options are ranked. > 2. by not always giving us the "center", it does permit learning about the > different viewpoints. Remember, since I'm middle-brow, I don't put as much > significance on optimizing within the distribution of political opinion > space. >
Balinski and Laraki studied a number of rules, and found that IRV and Plurality elected an extremist almost 100% of the time; Condorcet and Range elected a centrist almost 100%; and only Majority Judgment elected both centrists and extremists with about equal balance. So "learning about the different viewpoints does not favor IRV, but rather MJ. > 3. It introduces some uncertainty in the circulation of the elites, which > can give alternative viewpoints a chance to get a better hearing. When a > new third party gains ground, it'll get a serious hearing and hopefully the > de facto center will be moved. > Again, this actually argues for MJ more than IRV. JQ > > dlw > > ---- > Election-Methods mailing list - see http://electorama.com/em for list info > >
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