[EM] 28 years of progress and a wakeup call

[Kevin Venzke]

Hi CLC,

I think that WV Condorcet probably does get around "Monroe," at least given some
assumptions about voter behavior that I think are realistic. I don't relish the
idea of having to make that argument, but I think "Monroe" has limited scope. (It's
actually hard to understand what the scope of the claim is meant to be.)

The central problem with the methods Monroe investigates and then condemns is that
the methods don't have a way to know which contests are important. It seems that
voters opine on every pairwise contest, and if truncation exists at all it's just
interpreted away, the same as split votes. Burial strategies and counter-strategies
(which are also burial) will quickly confuse the scenario.

I quote how he explains the situation:

"All of these [paired comparison systems] ask for and use complex preference
information. All of them then give the incentive for voters to exaggerate their
preference differences over the most competitive alternatives up to the point where
it is unclear who the main competitors are. At this point all alternatives can win,
including alternatives that have absolutely nothing to recommend them except [that
they are on the ballot]. All paired comparison systems violate [Non-election of
Irrelevant Alternatives]; all of them are useless."

Monroe realizes he could use first preferences to help. He observes that if a
method satisfies majority favorite then it won't be as bad as Borda. But for the
most part he doesn't seem interested in exploring nuances. His writing is a little
hyperbolic.

He clearly doesn't mean to say that all methods based on the pairwise matrix are
bad, because his own proposal is still based on pairwise comparisons. It just
blocks candidates from winning who don't have any first preferences.

It's not at all demonstrated that you have to use first preferences as your cure;
this is just his view of the evidence. And because there isn't a general proof
regarding "paired comparison systems," it's not clear without further analysis that
"Monroe" applies to Condorcet//IRV or Condorcet//Approval(implicit), let's say. And
if it doesn't, that shows that there are avenues available to us.

Kevin
votingmethods.net




Closed Limelike Curves <closed.limelike.curves at gmail.com> a écrit :
> Why would Monroe (2001) not apply, unless you use the tied-at-the-top rule?
> 
> On Tue, May 21, 2024 at 2:09 PM Michael Ossipoff <email9648742 at gmail.com> wrote:
> > I meant that wv Condorcet can be relied on to elect the sincere CW, due to its
> > excellent deterrence of offensive-strategy.
> >
> > On Tue, May 21, 2024 at 14:00 Michael Ossipoff <email9648742 at gmail.com> wrote:
> >> What Meyerson & Weber demonstrated was that Approval’s Meyerson-Weber equilibrium
> >> is at the voter-median. i.e. Approval homes in on where the CW is.
> >>
> >> But, additionally, it seems to me that Approval has chosen the CW on every EM poll.
> >>
> >> Other than wv Condorcet, Condorcet’s won’t always elect the sincere CW, because
> >> of strategic-cycles.
> >>
> >> My & W also demonstrated that Plurality can keep on electing any pair of parties
> >> forever at MW-equilibrium.
> >>
> >> …which of course is what it’s doing now. (with a bit of help from mass-media
> >> promotion, & evidently at least occasional count-fraud.
> >>
> >> wv Condorcet will, because of how well it deters offensive-strategy.
>