[EM] 3 or more choices - Condorcet

[robert bristow-johnson]

On 10/1/12 12:16 PM, Kristofer Munsterhjelm wrote:
> On 10/01/2012 12:13 AM, Juho Laatu wrote:
>> On 30.9.2012, at 15.41, Kristofer Munsterhjelm wrote:
>
>>> As far as intrinsically Condorcet methods go, Ranked Pairs feels
>>> simple to me. The only tricky part is the indirect nature of the
>>> "unless it contradicts what you already affirmed" step.
>>
>> To me the biggest problem of path based methods is that there is no very
>> good real life explanation to why chains of pairwise victories are so
>> important. In real life the idea of not electiong a candidate that would
>> lose to someone who would lose to someone etc. doesn't sound like an
>> important criterion (since it doesn't talk about what the candidate is
>> like or how strong the opposition would be, but about what the set of
>> candidates and its network of relations looks like). Probably there will
>> never be a long chain of changes from one winner to another in real 
>> life.
>
> I don't think you need to go into path logic for Ranked Pairs. Rather, 
> how about this?
>
> "Because of the existence of cycles, it's obvious we need to discard 
> some of the data. So, what data do we discard? If we have to discard a 
> one-on-one victory, lets discard those that are as narrow, or involve 
> as few voters, as possible. Hence, we should go down the list of 
> one-on-one contests and add the data they give to our order unless it 
> would produce a cycle. That way, all the decisive contests get counted 
> first and if we have to throw some away, it's the weaker ones."
>

my spin is similar.  Ranked Pairs simply says that some "elections" (or 
"runoffs") speak more loudly than others.  those with higher margins are 
more definitive in expressing the will of the electorate than elections 
with small margins.  of course, a margin of zero is a tie and this says 
*nothing* regarding the will of the electorate, since it can go either way.

the reason i like margins over winning votes is that the margin, in vote 
count, is the product of the margin as a percent (that would be a 
measure of the decisiveness of the electorate) times the total number of 
votes (which is a measure of how important the election is).  so the 
margin in votes is the product of salience of the race times how 
decisive the decision is.

-- 

r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."