[EM] A distance based method

[Jameson Quinn]

2011/7/11 <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.
>

The point which Badinski and Laraki advocate is that neither all-centrists
nor all-extremists is good. I think that this second proposal is at least as
subject to center-squeeze as IRV, if not more, so like IRV it would class as
"too extremist" by their reckoning.

JQ


>
> ----- 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?
> > >
> > > ----
> > > Election-Methods mailing list - see http://electorama.com/em
> > for list info
> > >
> >
>
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