[EM] [CES #4445] Re: Looking at Condorcet

Dave Ketchum davek at clarityconnect.com
Thu Feb 9 19:55:48 PST 2012

On Feb 9, 2012, at 9:02 PM, Kevin Venzke wrote:
> Hi Robert,
> De : robert bristow-johnson <rbj at audioimagination.com>
> À : election-methods at lists.electorama.com
> Envoyé le : Jeudi 9 février 2012 10h07
> Objet : Re: [EM] [CES #4445] Re: Looking at Condorcet
> On 2/8/12 1:25 PM, Juho Laatu wrote:
> > On 8.2.2012, at 7.33, robert bristow-johnson wrote:
> >
> > ...
> >> if it's not the majority that rule, what's the alternative?
> > I'm not aware of any good alternatives to majority rule in  
> competitive two-candidate elections (with some extra assumptions  
> that rule out random ballot etc.).
> >
> > Juho
> thank you Juho, for stipulating to the obvious.  i will confess that  
> i am astonished at the resistance displayed here at the EM list to  
> this obvious fact.
> Nobody on EM said anything contrary to Juho's statement. I agree  
> with Juho. And Bryan said something similar at the end of his post.
> With two candidates, most of us agree that you have to use majority  
> rule. That doesn't mean it gives perfect answers according to some  
> ideal. If your ideal is maximum utility, then it's pretty clear  
> majority rule isn't always giving the correct answer. Not because  
> the ballots make it clear that this is happening, but because almost  
> any model of voter preferences will lead to this conclusion. It  
> would be frankly bizarre, if "fairness" and utility always gave the  
> same answers.

Actually, a majority is not needed here, but is close enough that we  
almost never complain.  For an excuse for making trouble I offer:
40 A
41 B
8   A,B  legal to vote for more than one in Condorcet.
8  spoiled ballots - can happen even here.
> (Your idea of all the utilities being 0 or 1 can't even be made to  
> work as a model, I don't think, unless voters really only have two  
> stances toward candidates. Because what happens when you introduce a  
> third candidate that some people like even better? Utilities don't  
> change based on who else is in the race, they are supposed to  
> represent in absolute terms the benefit from a candidate being  
> elected.)

Utilities do not change?  I buy that they do - given that A or B offer  
no special value and that neither is worth voting for, getting C in  
the race can matter if C is known as willing and able to be useful.
> When you try to make an argument for Condorcet and 3+ candidate  
> scenarios, based on the inevitability of using majority rule with  
> two candidates, you will fail to convince an advocate of utility,  
> because an advocate of utility probably doesn't think the method  
> options are as limited anymore, once you have 3+ candidates. The  
> majority rule procedure with two candidates may be necessary (Clay  
> may even disagree with that though), but that doesn't mean it was  
> always doing the right thing.

Those of us that dislike runoffs might argue against demanding  
majority in what follows :
40 A
30 B
15 C>B>A

I count 45B>40A, 30B>15C, 40A>15C  - with B winning if we do not  
demand majority
> Is this clear enough? I understand you want to make a fairness  
> argument in favor of majority rule with two candidates, and then  
> build off of that. But a utility advocate may reject fairness and  
> prefer utility, even without offering a different method that could  
> be used with two candidates. (He may perceive that there is no  
> utility improvement to be had by doing something else.) So even if  
> you attack Range as silly in the two-candidate case, you're not  
> making the point that fairness is paramount over utility.

Seems to me the voters saw utility - but there is nothing here giving  
it a measurable value because there is nothing to measure it with  
other than the vote counts (but it is the vote counts that show how  
much they saw backing the value they voted for).
> I'd note also that utility goes far beyond the question of whether  
> Range is a workable method. A utility advocate is free to leave  
> Range in the trash-bin while seeking to maximize utility under other  
> methods that you might recognize as less prone to exaggeration  
> strategies.
> And from your last mail to me:
> >> It could be true if it so happens that nobody wants to vote  
> truthfully under
> >> Condorcet methods, while Approval in practice never has any bad  
> outcomes, etc.
> >
> >it could be true that hundreds of people who have testified to such  
> have actually been abducted by extraterrestrial aliens who poked  
> needles into them
> >and did experiments on human subjects.  but it's an extraordinary  
> claim that requires extraordinary evidence.
> Yes, you're right. However, the important point here is just that it  
> could be true. "More Condorcet than Condorcet" isn't inherently  
> nonsense. You just have to read it as "better sincere Condorcet  
> efficiency than under Condorcet methods." Such a thing is possible.
> Kevin
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