[EM] IRV inconsistency

[Markus Schulze]

Dear Forest,

you wrote (15 May 2001):
> When there is no Condorcet winner in either of the precincts (or
> in the dominant precinct) then there is a fundamental ambiguity
> (i.e. lack of information) that even preserving all of the available
> information may not resolve except by combining the results, which
> may give a surer result, but not always one that is totally without
> ambiguity. This does not contradict common sense.

You wrote (15 May 2001):
> It is only in the fundamentally ambiguous (no CW) cases that
> Condorcet methods fail these criteria, while IRV fails without
> provocation or mitigating circumstances, as I have shown in other
> postings.

You wrote (16 May 2001):
> A Condorcet failure of consistency will only be in the case when
> one or more of the two precincts fails to have a Condorcet winner.

You wrote (16 May 2001):
> Any Condorcet method that fails the RSC does so only in cases
> where there is no Condorcet Winner.

I see the danger that you formulate your desiderata in such a
manner that they are either meaningless (when the reader doesn't
consider the Condorcet criterion important) or trivial (when the
reader considers the Condorcet criterion important).

It doesn't make much sense to criticize IRV for violating the
consistency criterion and then to promote Condorcet methods and
to say that a violation of the consistency criterion is not a
problem when the used election method meets the Condorcet criterion.
And it doesn't make much sense to criticize IRV for violating
reversal symmetry and then to promote a Condorcet method that
violates reversal symmetry and to say that a violation of reversal
symmetry is not a problem when the used election method meets the
Condorcet criterion. As Blake Cretney wrote to Mike Ossipoff
(16 Apr 2001):

> You must admit that if you rail against IRV's non-monotonicity,
> and then propose a method that is non-monotonic, you're going to
> run into some rhetorical problems.

Markus Schulze