[EM] RCV Challenge

[Kevin Venzke]

Hi Robert,

Le samedi 25 décembre 2021, 21:06:28 UTC−6, robert bristow-johnson <rbj at audioimagination.com> a écrit :
> > In the three-candidate case Condorcet//FPP should be the same thing as BTR-IRV,
> > except with greater clarity, as you point out, about how the method will play out
> > in general. I value that a lot.
> >
> > It won't be my own favorite method, just because my main interest is in reducing
> > compromise incentive (or: minimizing the appearance that some candidate was a
> > spoiler).
> >
> > The question of how gameable it is, vs. certain other methods, is interesting.
> > I'll leave it for now. But it didn't occur to me to think it was the worst or
> > most gameable rule.
> 
> Hi Kevin,
> 
> 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.  In Burlington 2009, if
> 371 or more Wright voters that disliked Kiss the most had conspired to compromise
> their vote and rank Montroll over Wright and snatch the election away from Kiss.
> Would that be "gaming the system"?
> 
> I just thought that any vulnerability to a spoiler pathology can be used to some
> side's advantage.

I don't have a personal definition for "gaming." It could certainly include any
instance where voters vote insincerely in order to get a better result. However,
people tend to have a more negative opinion of strategies like burial, where the
voter completely fabricates a preference.

With compromise strategy, attitudes are usually different. Picture under FPP the
Nader voter (to use an old example) who can vote sincerely for Nader or
strategically for Gore. If he votes for Nader, his least favorite candidate Bush
wins. If he votes for Gore, at least his second choice Gore will win. A common
feeling is that the Nader voter shouldn't have to make this decision. That, if
Nader is not a viable candidate then the method itself should, effectively,
execute the strategy on the Nader voter's behalf. (Or, equivalently, if the
method can tell that Nader isn't viable, then it should drop him out of the race
as part of the algorithm, such that the result is undisturbed whether he has
entered the race or not.)

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. And also on Nader, the candidate, there is less
pressure to drop out of the race if he isn't going to win it. There should be
potentially more choices available on the ballot, and more voters feeling safe
to indicate preferences for those choices.

Burlington looks much the same to me. If some Republicans abandoned their first
preference candidate to stop the Progressive from winning, 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