[EM] CVD wants Alt.V to be fairer but it isn't: misleading website

[Markus Schulze]

Dear Mike,

you wrote (2 Oct 2000):
> IRV, in examples like that, fails to elect the SCW, even when he's
> the favorite of more people than any other candidate is. At least
> FPP won't do that.

Of course, it is also possible to create examples where IRV chooses
a SCW and FPP doesn't.

******

You wrote (2 Oct 2000):
> Can I call that IFCC? Doesn't IFCC say that if we delete from the
> ballots 1 or more candidates from a clone set, and recount the ballots,
> that shouldn't change the matter of whether or not the winner comes
> from that clone set?
>
> That doesn't seem very useful. If we turn it around and add clones,
> and hold a new balloting after adding them, the criterion only applies
> if no one changes their vote.
>
> How likely is it that no one would vote differently if new candidates
> are added? A criterion that assumes that seems real useless.
>
> The IFCC would be more useful if it spoke of adding candidates and
> holding a new balloting in which voters don't necessarily vote the same
> way, but whose votes or vote-changes are somehow constrained.
>
> For instance, maybe they always vote to maximize their utility
> expectation (we then have to specify utilities in our examples),
> or maybe they just always vote in an undominated way. Maybe, then, they
> don't change their vote unless to not do so would result in a dominated
> strategy. These are just possibilities that I mention. But saying that
> they don't change their vote is entirely unrealistic.
>
> So say a method meets IFCC. Would it meet a more realistic version?
> Maybe not, and so I suggest that meeting IFCC doesn't mean a whole lot.

I don't believe that you don't consider independence from clones to be
important. Otherwise you would concentrate only on PC and you wouldn't
promote three methods in your http://electionmethods.org website.

PC is the best Condorcet method when one concentrates only on
strategical voting and ignores strategical nomination. PC meets
Saari's positive involvement criterion and Fishburn's no-show
criterion. PC guarantees that a dichotomous voter cannot be
punished for showing up and voting sincerely.

PC isn't vulnerable to what Steve calls "indirect strategies."
That means: If PC is used then it isn't possible to change the
winner from candidate A to candidate B by ranking two different
candidates C and D insincerely to each other.

Therefore when you don't consider independence from clones to
be important then why do you promote more methods than just PC?

Markus Schulze
schulze at sol.physik.tu-berlin.de
schulze at math.tu-berlin.de
markusschulze at planet-interkom.de