You can read the paper - I linked it - if you want to. Without going back and quoting them, basically they argued that if a method always elects centrists, candidates will always be competing to be the "most centrist", which will make it difficult for voters to make a meaningful choice. They also argue that if a method almost always elects extremists (as with Plurality in their simulation), the political culture will become one of extremism and polarization. I would argue that this latter effect is clearly visible in US politics.
Note that their definition of "centrist" and "extremist" was based entirely on a single election, the 2007 French presidential election. They ran 10K simulations of variants of this same election, seeded by real polling data. (You can also see a summary of their results on wikipedia<http://en.wikipedia.org/wiki/Voting_systems#Experimental_criteria>.) That's enough data to clearly show some differences between systems, but it's not clear how robust those differences are under different conditions. 2011/7/11 Juho Laatu <[email protected]> > Do you know remember their arguments, or your own, on why centrists are not > good? I think methods that elect centrists (like CW) are quite good general > purpose single-winner methods. But on the other hand there are many kind of > single-winner elections, and in many cases the targets may well be very > different. > > Some thoughts on why we might not recommend not always electing a > "centrist" candidate: > - we want to alternate between different parties, not to elect from the > "centrist" party every time > - we want to have proportional representation of all parties in time (based > on lottery or credit votes) > - we want to elect from major parties (not from _small_ centrist parties) > - we want to have a system that exaggerates small changes in balance so > that the policy will always reflect the current needs and tendencies > (electing centrists may lead to having no changes in the policy and voters > having no influence on the policy) > > We could also have different definitions of what "centrist" means. Maybe > the second option below is the default value. > - no extreme opinions in any questions (close to median opinion in all > questions) (= "median opinions") > - second preference of many voters, or typically in the first half of the > individual rankings, close to being a Condorcet winner (= "good in pairwise > comparisons") > - accepted or ranked quite high by many voters in all parties / segments of > the society (= "wide support") > > Juho > > > > On 11.7.2011, at 13.06, Jameson Quinn wrote: > > This system seems explicitly designed to elect a centrist. In their > experimental > paper<https://sites.google.com/site/ridalaraki/xfiles/BalinskiLarakiExperiEvid%28LastVersion%29.pdf?attredirects=0>on > Majority Judgment, system inventors Badinski and Laraki run a simulation > to see how often different systems elect a centrist. Most systems they test > either elect the centrist almost always (ie, condorcet systems) or almost > never (plurality, IRV, runoffs), but their MJ system does about half the > time. They argue that this "lack of bias" either towards or away from > centrists is best, because a system which is too skewed to the middle or to > the extremes will distort the political dialogue in corresponding ways. > Though I think their simulation is just a rudimentary first step, I find > their normative argument convincing; and so I don't really like this > "distance" method. > > JQ > > 2011/7/10 <[email protected]> > >> First find a clone consistent way of defining distance between candidates. >> >> Then while two or more candidates remain >> of the two with the greatest distance from each other >> eliminate the one with the greatest pairwise defeat >> EndWhile. >> >> Various variants are possble. For example, you could count defeats only >> from the remaining >> candidates. Also there are various possible measures of defeat strength. >> In that regard, if you say that >> any defeat by covering is stronger than every non-covering defeat, then >> the method will always elect a >> covered candidate. >> >> To get a distance estimate in a large election you could just ask each >> voter to list the pair of candidates >> that seem the most different on the issue or combination of issues of most >> concern (to that voter). The >> pair submitted by the greatest number of voters would be the first pair >> considered, etc. >> >> What potential for manipulation does this direct approach introduce? >> >> Perhaps voters would try to pit their favorites' rivals against each >> other. Would that be insincere? Not if >> they consider their favorite to have a reasonable middle of the road >> position, while viewing the rivals as >> being at opposite unreasonable extremes. >> >> What indirect measure of distance could be used? >> >> If we count the number of ballots on which candidates X and Y are ranked >> at opposite extremes (top >> rank for one versus unranked for the other), the monotonicity of the >> method would probably be >> destroyed. Is there a more subtle way of inferring the distance that >> wouldn't destroy the monotonicity? >> >> ---- >> Election-Methods mailing list - see http://electorama.com/em for list >> info >> > > ---- > Election-Methods mailing list - see http://electorama.com/em for list info > > > > ---- > Election-Methods mailing list - see http://electorama.com/em for list info > >
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