[EM] Centrist vs. non-Centrists (was A distance based method)

2011-07-13 Thread fsimmons
Jameson, I'm surprised that you consider a Condorcet method to be too extremist or apt to suffer center squeeze. Think Yee diagrams; all Condorcet methods yield identical diagrams, while center squeeze shows up clearly in methods that allow it. Of course if we have a multiwinner method, we

[EM] Yee diagrams and Condorcet (was Centrist vs. non-Centrists (was A distance based method))

2011-07-13 Thread Bob Richard
On 7/13/2011 11:14 AM, fsimm...@pcc.edu wrote: Jameson, I'm surprised that you consider a Condorcet method to be too extremist or apt to suffer center squeeze. Think Yee diagrams; all Condorcet methods yield identical diagrams, while center squeeze shows up clearly in methods that allow it.

Re: [EM] Centrist vs. non-Centrists (was A distance based method)

2011-07-13 Thread Jameson Quinn
2011/7/13 fsimm...@pcc.edu Jameson, I'm surprised that you consider a Condorcet method to be too extremist or apt to suffer center squeeze. Hmm... you're right, I hadn't recognized that your remove one of closest pair method was Condorcet-compliant, as any pairwise method. Think Yee

Re: [EM] Yee diagrams and Condorcet (was Centrist vs. non-Centrists (was A distance based method))

2011-07-13 Thread Kristofer Munsterhjelm
Bob Richard wrote: On 7/13/2011 11:14 AM, fsimm...@pcc.edu wrote: Jameson, I'm surprised that you consider a Condorcet method to be too extremist or apt to suffer center squeeze. Think Yee diagrams; all Condorcet methods yield identical diagrams, while center squeeze shows up clearly in

Re: [EM] Centrist vs. non-Centrists (was A distance based method)

2011-07-13 Thread Jameson Quinn
2011/7/13 Kristofer Munsterhjelm km_el...@lavabit.com fsimm...@pcc.edu wrote: Of course if we have a multiwinner method, we don't want all of the winners concentrated in the center of the population. That's why we have Proportional Repsentation. Also the purpose of stochastic single

Re: [EM] A distance based method

2011-07-13 Thread Kristofer Munsterhjelm
fsimm...@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

Re: [EM] Yee diagrams and Condorcet (was Centrist vs. non-Centrists (was A distance based method))

2011-07-13 Thread Bob Richard
After looking up some old email threads, it now seems to me that I made a significant mistake in the post below. It is true that the model underlying Yee diagrams guarantees that there will always be a Condorcet winner. But apparently that has nothing to do with the two dimensions being

Re: [EM] Centrist vs. non-Centrists (was A distance based method)

2011-07-13 Thread fsimmons
- Original Message - From: Kristofer Munsterhjelm fsimm...@pcc.edu wrote: ... There may also be another scenario where Majority Judgement (or median ratings, for that matter) would do better than ranked methods. If it's possible for the voters to agree on what, say, Good means

Re: [EM] Yee diagrams and Condorcet

2011-07-13 Thread fsimmons
Actually, any centrally symmetric distribution will do, no matter how many dimensions. The property that we need about central symmetry is this: any plane (or hyper-plane in higher dimensions) that contains the center of symmetry C will have equal numbers of voters on each side of the

Re: [EM] Centrist vs. non-Centrists (was A distance based method)

2011-07-13 Thread Jameson Quinn
2011/7/13 fsimm...@pcc.edu - Original Message - From: Kristofer Munsterhjelm fsimm...@pcc.edu wrote: ... There may also be another scenario where Majority Judgement (or median ratings, for that matter) would do better than ranked methods. If it's possible for the voters

Re: [EM] Yee diagrams and Condorcet

2011-07-13 Thread Jameson Quinn
That proof assumes a euclidean distance metric. With a non-Euclidean one, the planes could have kinks in them. I believe I have heard that the result still holds with, for instance, a city-block metric, but I cannot intuitively demonstrate it to myself by imagining volumes and planes as in this

Re: [EM] Yee diagrams and Condorcet

2011-07-13 Thread fsimmons
If we abandon the Euclidean metric, then we also abandon Voronoi Polygons; the corresponding idea for more general metrics is that of a Dirichlet region. It would be amusing to see Yee diagrams based on L_1 and L_infinity metrics Of course, Yee uses the L_2 metric to make his pictures

Re: [EM] A distance based method

2011-07-13 Thread Jameson Quinn
I doubt it's monotonic, though it's probably not a practical problem. That is, it would probably be totally impractical to try to use the nonmonotonicity for anything strategic, and it wouldn't even lead to Yee diagram ugliness. 2011/7/13 fsimm...@pcc.edu Here's a simpler version that is

Re: [EM] A distance based method

2011-07-13 Thread Kristofer Munsterhjelm
fsimm...@pcc.edu wrote: Here's a simpler version that is basically the same: Make use of cardinal ratings so that the rating of candidate X on ballot b is given by b(X). Define the closeness of candidate X to candidate Y as the dot product Sum b(X)*b(Y) where the sum is taken over all b in