[EM] RCV Challenge

Forest Simmons forest.simmons21 at gmail.com
Mon Dec 27 21:56:06 PST 2021


You wrote ...

"I'm just a Condorcet guy.  How cycles get resolved is less motivating to
me than insuring that the Condorcet winner is always elected"

But "how cycles get resolved" has a big influence on whether or not they
come into existence.  And when these cycles are created, the sincere
Condorcet Winner goes out the window ... no longer showing up as a
"beats-all" candidate on the ballot set. Can the cycle resolution method
reconstruct the lost CW? All bets are off.

The easier it is to game the cycle resolution method, the more incentive
for the gamers to create the cycles.

It seems that most Condorcet cycles are artificially created.

For example, one way to create a cycle is by an insincere rank reversal
technique called "burial".

If the cycle resolution method has no built in disincentive/negative
feedback for this (or any other) kind of cycle creation, over time the
gamers find out that they can manipulate elections to their advantage with
impunity, so that artificially created cycles become more and more common,
giving the false impression that cycles are a normal fact of nature.

Naive voters are easy prey for sophisticated gamers unless the method
designers engineer manipulation resistant safe-guards into the method.

And that is really the only essential thing that distinguishes one
Condorcet method from another ... what to do if there is a cycle, and how
to make sure that opportunistic creators of cycles are not rewarded for
their perfidy.

So cycle resolution has to be the main concern of Condorcet method
engineers, but it should be no concern at all for the voters. That's why
seamless incorporation of the cycle resolution is so important.

Take the following RCV method for example:

Elect the candidate which on the most ballots beats, both in rank and
pairwise, every candidate unranked by that ballot.

This succinct 20 word method definition makes no mention of cycles or
Condorcet winners or majorities whatsoever, yet it completely resolves all
cycles automatically, disincentivizes manipulators, and reliably elects the
resulting vouch safed Condorcet Winner.

The voter can drive the car so-to-speak, without worrying about the
machinery under the hood.


El lun., 27 de dic. de 2021 7:35 p. m., robert bristow-johnson <
rbj at audioimagination.com> escribió:

> > On 12/26/2021 1:38 PM Kevin Venzke <stepjak at yahoo.fr> wrote:
> >
> >
> > Le samedi 25 décembre 2021, 21:06:28 UTC−6, robert bristow-johnson <
> rbj at audioimagination.com> a écrit :
> ...
> > >
> > > If there are conditions that can make a candidate a spoiler, can't
> that be used in
> > > some way to swing the election?
> >
> > Yes, I think by definition.
> >
> > > I mean, it depends on what you call "gaming" an election.
> ...
> > So the voter tells the method what he wants, and the method should
> represent his
> > interests. In theory the voter then doesn't need to misrepresent
> preferences by
> > prematurely compromising.
> ...
> > Burlington looks much the same to me. ... you could call it
> > "gaming" on their part, but any Condorcet advocate will sooner argue
> that they
> > shouldn't need to do this, that the result they gain from strategizing
> in this
> > IRV election is actually what they are entitled to naturally.
> Kevin, I **totally** agree.
> I'm just a Condorcet guy.  How cycles get resolved is less motivating to
> me than insuring that the Condorcet winner is always elected.  (And the
> simplest legislative language that accomplishes that goal is usually what I
> advocate.)
> BTW, my little RCV paper about Burlington 2009 has been getting more
> developed.  Now with figures in color sorta spelling out the Center Squeeze
> effect.
>  https://drive.google.com/file/d/1jIhFQfEoxSdyRz5SqEjZotbVDx4xshwM/view
> I hope some of you guys might take a look at it, if you hadn't before.
> --
> r b-j . _ . _ . _ . _ rbj at audioimagination.com
> "Imagination is more important than knowledge."
> .
> .
> .
> ----
> Election-Methods mailing list - see https://electorama.com/em for list
> info
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