[EM] Condorcet Criterion for plurality.

[MIKE OSSIPOFF]

Markus said:

>Dear participants,
>
>it is clear why Mike Ossipoff is unwilling to understand that
>plurality can be defined on preferential ballots

I don't know whom you're replying to, Markus. You're not replying
to me, and you apparently didn't read my previous message about this.
You post replies without reading or understanding what you're replying
to, just as you expound on academic criterion compliance determination
without understanding it and without being able to define the
procedure you're talking about.

In my previous posting about this, yesterday, I made it clear that
I'm not saying that Plurality can't be defined in Markus's contrafactual
way. I merely said that it's sloppy, shabby, & funky when a criterion
can't be made to apply to all methods without inventing a different
definition for some of them. I also said that, however Markus says
that Plurality can be defined, he hasn't defined his approach to
criterion compliance determination until he answers the questions that
I (and others) asked. Does he have special definitions for Approval
and single-winner Cumulative, in order to be able to apply the criteria
to them too? If so what are they? Or does he have a general rule
for getting from the voted ratings (or rankings?) the information that
the voting system needs, and would, in real life, get from its own
ballots? If so what is that general rule?

I've asked these questions repeatedly but Markus chooses to repeat
one statement over & over, instead of answering the questions.
Yes, Markus, we know that Plurality can be defined any way you want
to define it, ok? Now, can you answer the questions and define your
approach to criterion compliance, the one that you keep vaguely
referring to? Answer the questions in the previous paragraph, if
you can. If you can't, you really need to find out more about what
you're talking about.

As for whether Plurality is better than IRV: IRV is nonmonotonic.
A number of authors agree that that disqualifies IRV from serious
consideration. Plurality is monotonic and IRV is nonmonotonic.
There are many who would say that alone makes Plurality better than
IRV. That's without even counting Participation, etc. Additionally,
Plurality, like Approval & Condorcet can have the bulk of its counting
done locally, and those results can be summed at the central count
location later, whereas IRV requires all the rankings to be simultaneously 
stored, and for all of them to be processed in one big
computational task.

So yes, Markus, Plurality is better than IRV in many important ways.
Is Plurality better than IRV? Of course questions like that are
subjective, but my opinion would be yes, Plurality is better than
IRV. Remember that, by defensive strategy criteria, IRV offers
no improvement over Plurality. All you can say for IRV against
Plurality is that IRV lets you vote Nader 1st, as long as you're sure
that Nader is a sure loser. Some of us don't find that at all
encouraging as an advantage for IRV.

Mike Ossipoff



: He wants to be
>able to claim that plurality meets the Independence from Irrelevant
>Alternatives Criterion (IIAC). He wants to be able to claim that
>even plurality was better than IRV.
>
>Mike Ossipoff wrote (10 Nov 2000):
> > There are certainly a number of ways in which Plurality is better
> > than IRV: Participation, IIAC, Consistency, etc.
>
>Mike Ossipoff wrote to Blake Cretney (13 Nov 2000):
> > Here's what I think is meant by IIAC: Deleting a loser from the
> > ballots, and then recounting those ballots, should never change who
> > wins. It _is_ meaningful to say that Approval & Plurality meet this
> > simple criterion.
>
>Mike Ossipoff wrote to Blake Cretney (14 Nov 2000):
> > It isn't at all clear why you think that it's meaningless that
> > Approval and Plurality pass IIAC. On the contrary, it's very relevant,
> > because IRVies, as I said, always bring up Arrow. IIAC isn't one of
> > the criteria important to me, but it's quite relevant because Arrow
> > is brought up so often. You seem to be saying that the relevance of
> > a method passing IIAC depends on whether that method is a rank method,
> > and it isn't at all clear why you believe that. Criteria are written
> > because someone is saying that they're desirable to comply with. If
> > a method complies, it complies, regardless of its balloting or other
> > procedural details.
>
>Markus Schulze
>

_____________________________________________________________________________________
Get more from the Web.  FREE MSN Explorer download : http://explorer.msn.com