[Election-Methods] RE : Re: Is the Condorcet winner always the best?

Diego Santos diego.renato at gmail.com
Wed Dec 12 03:50:37 PST 2007

I was not enough clear when i wrote my previous email. The '>>' is not a
real approval mark on the ballot, it was only a "satisfaction limit" from
each voter. I am arguing that not always the Condorcet winner is the one
that maximizes happiness of the people, as Jonathan pointed.

A "approval quorum" rule will avoid low utility CW to win. And, opposit to
Jonanthan argument, an approval cuttoff does not add too much complexity: it
is like a hypothetical candidate NOTB (none of the below).

2007/12/11, Dave Ketchum <davek at clarityconnect.com>:
> On Tue, 11 Dec 2007 12:20:49 -0800 Jonathan Lundell wrote:
> > On Dec 11, 2007, at 6:05 AM, Kevin Venzke wrote:
> >
> >
> >>Jonathan,
> >>
> >>--- Jonathan Lundell <jlundell at pobox.com> a écrit :
> >>
> >>>...should choose B as a good compromise, with the A voters saying A
> >>>is
> >>>good, B OK, C very bad. But Diego's profile suggests to me that the A
> >>>voters are saying something like A is good, B is bad, C is very bad.
> >>>Not that they can express it in a normal linear ballot, just that
> >>>we're being told a little more about their opinions.
> >>
> >>In my opinion, to the extent that the effect of a ">>bad>verybad"
> >>vote is
> >>disregarded, the point of letting voters indicate such preferences is
> >>undermined anyway.
> >
> >
> > I'm not advocating it as a ballot option, only as a meta-notation
> > shorthand to give us kibitzers a little more information about the
> > voters' utility functions.
> >
> >
> >>
> >>>In my example, the effect of a later-no-harm voting rule is evident.
> >>>In Diego's, a rule (such as STV) that elects A doesn't seem
> >>>unreasonable to me.
> >>>
> >>>The problem is that with an ordinary linear ballot (no '>>'), we
> >>>can't
> >>>distinguish between the cases. Not that I'm arguing that we should
> >>>employ '>>'; offhand, that strikes me as a complication to be
> >>>avoided.
> >>
> >>In one sense I don't agree. If >> is allowed then apparently it's
> >>safe to
> >>vote ">>bad>verybad." If >> isn't allowed then voters will probably
> >>be more
> >>cautious, since the method could very well take them as serious if
> >>they say
> >>that bad is better than verybad.
> >>
> >>I tend to think that if B doesn't win in Diego's scenario, the
> >>method is
> >>second-guessing the voters. It either disbelieves the C voters'
> >>preference
> >>for B over A, or finds that there's something more important than
> >>majority
> >>rule.
> >
> >
> > There's a reasonable argument to be made (hardly originally by me) on
> > either side of the question of whether a compromise candidate is
> > sometimes (or always) better to the candidate of one faction in a
> > close election.
> >
> > If the vote were:
> >
> > 53 A
> > 47 C
> >
> > ...we'd shrug and call it a fairly close election, or at least no
> > landslide, and forget about it, even if all 100 voters strongly
> > disapproved of the opposing candidate. If we introduce a third
> > candidate whom the A and C voters despise only slightly less than C
> > and A respectively, and end up with something like Diego's profile, we
> > have 100 (or 90 in that profile) unhappy voters instead of 47.
> A and C agree that B is better than their standard enemy.
> C voters will be happy to help install B, since this is better than
> installing A.  A voters may be a bit unhappy, but they at least avoided
> installing C.

Probably A supporters will be too unhappy, because their favorite candidate
would win if B was not nominated.

> > I'm not saying that it's unarguable, nor that the voting system should
> > somehow anticipate the situation (through the use of '>>', for
> > example). I think it's a fuzzy case with no perfect answer, and that
> > we don't really want to make the ballot more complex, or add to the
> > possibilities for manipulation that such a rule would entail. I'm just
> > saying that it's not obvious that, in all cases, the best rule is the
> > one that lets B win.
> Choices can be hard.  Get far enough from a tie and A or C will win.  If
> we manage a cycle we can debate the results of that.
> --
>   davek at clarityconnect.com    people.clarityconnect.com/webpages3/davek
>   Dave Ketchum   108 Halstead Ave, Owego, NY  13827-1708   607-687-5026
>             Do to no one what you would not want done to you.
>                   If you want peace, work for justice.
> ----
> Election-Methods mailing list - see http://electorama.com/em for list info

Diego Santos
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