[EM] metrics on elections

[Kristofer Munsterhjelm]

Stephen Turner wrote:
> Hello.  It's been quite a while since
> I posted here.  I have a question: does
> anyone have any good pointers
> to material on metrics on elections?
> 
> A "metric" is as usual, and an
> "election" would be simply an
> election profile, that is you have
> some set S of permitted ballot types,
> and so many ballots of type 1, so many of
> type 2, ...

I'm not sure about election profiles, but when dealing with ranking, 
there's the Kendall-tau (Bubble sort, Kemeny) distance. The distance 
between two orderings (such as ranked ballots) is equal to the number of 
pairs that these rank in different order.

Optimizing to find the social ordering that has the least total 
Kendall-tau distance to all ballots in a profile makes Kemeny's method.