[EM] reply to venzke re utility, approval, range

[Kevin Venzke]

Warren,

--- Warren Smith <wds at math.temple.edu> a écrit :
> >Venzke:
> THIS IS useful TO know, since it means that the range voter's greater
> ability to express himself (relative to the approval voter) isn't part
> of why WDS feels social utility IS a useful measure. That means there's
> no reason to discuss only range, since approval should justify the use
> of social utility to the same extent that range does.
> 
> --WDS: I agree: that is fully correct IF we have strategic voters only.
> But if there are some honest voters, though, THEN range and approval will
> differ.

Sure, they'll differ in terms of *performance*, but I'm talking about
their use in *justifying* social utility. According to you, social 
utility is a useful measure even if voters are never sincere and always
strategic. Right?

> --WDS: Your sims were more extensive than mine in various ways, at least
> as far as
> the schulze vs approval comparison is concerned.
> However your sims are somewhat unfair in that your approval voters are
> strategic in a number of possible ways, but meanwhile your Schulze voters
> are always
> honest and thus never suffer from, e.g. DH3 pathology, which would have
> led to
> heavy utility decreases for strategic Schulze which your sim could not
> detect.
> That gave Schulze a large a priori advantage over approval in
> many of your sims.  Nevertheless approval often did better than Schulze
> in your sims.

Well, I wouldn't test the effects of DH3 pathology. If we imagine that
the Schulze voters suffer from this pathology, then there isn't much point
in testing Schulze, is there?

It would, however, be useful to test what happens when Schulze voters
compress the top ranks and truncate the lower ones. Both of these make
Schulze more like Approval, though. I imagine you don't want to propose
that this would make Schulze perform *worse*.

> The particular sim you just talked about seems to involve fairly honest
> approval voters.
> It looks like from two of your sims that if the approval voters have a
> pretty good idea
> of (1) their own private utilities, and (2) of the names of some
> candidates
> that society considers good (e.g. the true util maxer or the the Schulze
> winner),
> then the threshold strategy is good enough to make approval voters using
> that strategy
> produce better election results than Schulze (with honest voters)
> produces.  It would be more
> reassuring if more sims of this ilk were run, using more thresholds.  For
> example, try
> 80% estimated prob for Schulze or MaxUtil winner.  Or try using the
> utility between
> A's and B's which is 95% of the way toward B (assuming that voter prefers
> B>A)
> as threshold.  That might lead to a more realistic sim.

I think both of these scenarios are highly unrealistic. I think almost
any of the others are worth more attention: Two Evils, Zero-Info,
Acceptables, Bullet-Voting, and even First-Pref Proportion seem somewhat
plausible.

> >Venzke: I assume that you did test approval strategy.
> 
> --WDS: yes: I considered both honest approval voters, honest range
> voters,
> and strategic approval = strategic range voters.  The honest range voters
> did not do any downweighting: they voted 100 for the favorite
> and 0 for the most hated, that was my definition of honesty for that
> purpose.

What did honest approval voters do?

Kevin Venzke



	

	
		
___________________________________________________________________________ 
Appel audio GRATUIT partout dans le monde avec le nouveau Yahoo! Messenger 
Téléchargez cette version sur http://fr.messenger.yahoo.com