[EM] "scored condorcet", etc

Rob Brown rob at karmatics.com
Wed Nov 23 10:00:06 PST 2005


Kevin Venzke <stepjak <at> yahoo.fr> writes:
> > However, I'm still unable to picture the real world consequenses of
> > minsum/dodgson's problems. Similar candidates would help each other, 
> 
> But this means that factions can deliberately nominate multiple candidates
> solely because it may help, and can't hurt, assuming other voters ignore
> the clones (rather than trying to do something strategic with them).

Well, I suppose in theory they could, but I don't see that it would be wise for
them to do it.  Whatever slight advantage it may give them to, say, put another
candidate out there would probably be far outweighed by the effort they have to
go to (i.e. money they must spend) to promote another candidate. 

Regardless, I'm not pushing for MinSum.  MinMax is groovy.

Can you give me a real world scenario where having minmax could cause problems?
   I don't think it's a hugely horrible thing to have a slightly "less
preferred" candidate elected.  What is a problem is when the whole structure of
politics centers around a strategy for manipulating the voting system, which is
what I see in the US today.  It's about priorities to me.

> You have to decide what causes this partisanship, and then you can identify
> criteria which address the problem. I'd say the problem is caused in
> large part by the fact that only the two candidates most perceived to 
> be viable can expect to receive votes.

Well, I think it's obvious what causes partisanship in plurality.  Eliminating
similar candidates prior to the election has MASSIVE strategic advantage.  This
should be common sense to anyone who has ever had a group of people who vote on
which movie to see: "Hey, sci fi buffs.....let's decide between us whether we
all vote for 'Serenity' or for "Hitchhiker's Guide", or we're gonna be outvoted
by the ones who want to watch the lame chick flick".

Almost ANY semi-reasonable election system would eliminate this effect in a
simple situation like that: beatpath, minmax, minsum, copeland, irv, approval,
range, hell probably even borda.

In another post I mentioned my goofy little article on the Moose Lodge, which I
think does a pretty good job of showing how easy it is for parties (or
"strategic clusters") form.

 http://www.karmatics.com/voting/moose-example.html

> > I have no problem with MinMax, I only explored MinSum, which I now see is
> > called
> > Dodgson, because I hadn't seen it discussed.  Minmax is fine.
> 
> (Just to say it again, I don't think MinSum should be called "Dodgson."
> You can't find the Dodgson winner just from the pairwise matrix. You
> have to count movement on the actual ballots. Summing the defeat margins
> is just an approximation of this.)

Ok, I'll call it MinSum.  Is that actually what others call it?  I just made up
the name.  But I probably won't talk about it any more because you've convinced
me MinMax is better.  So no more using it as a straw man, ok? ;)

-rob




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