[EM] A distance based method

[fsimmons at pcc.edu]

Yes, by sequentially eliminating one member of the remaining largest diameter pair, the method elects a 
centrist.

If this is considered a problem, it can be overcome by sequentially eliminating one member of the 
current smallest diameter pair.  However, this variant introduces a strong incentive for compromise, 
which is nil in the other version.

----- Original Message -----
From: Jameson Quinn 
> This system seems explicitly designed to elect a centrist. In their
> experimental 
> paperonMajority 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 
> 
> > 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?
> >
> > ----
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