[EM] A distance based method

[Kristofer Munsterhjelm]

fsimmons at pcc.edu wrote:
> Trying to build a metric from a set of ranked ballots is fraught with
> difficulties, and your outline of a procedure for doing it is
> interesting to me.
> 
> The simplest, least sophisticated idea I have so far that seems to
> have some use is to define the distance between two candidates X and
> Y to be the number of ballots on which at least one of the two is 
> truncated.

I'm not sure if that really works. It could give a rough distance 
between zones of acceptable and unacceptable candidates, but beyond that 
it gets less reliable. To take a Norwegian example: we have two broad 
coalitions: one that's left-of-center and one that's right-of-center. 
Say I prefer the left-of-center coalition. I would still rank the 
right-of-center coalition's individual parties because "if I have to get 
one of them, I could at least try to pull them as close as possible to 
my view".

Popularity could also be a factor. In a Bush-Gore-Nader setting, voters 
might rank Bush, Gore, and Nader, but skip Browne, Hagelin, and Phillips.

(Truncation would also pose a problem to the inference idea I gave in my 
earlier post. In general, noise or variety in the amount of information 
provided, in any manner, would. But it makes sense to consider perfect 
situations before going to imperfect ones.)