[Election-Methods] RELEASE: Instant Runoff Voting

[Chris Benham]

Kathy,
All of your points have already been addressed in my paper or by Abd
ul Rahman Lomax on this list.

For example, re "later no harm":

I gather you are referring to Abd's  "Dopp: 15. “Violates some election fairness principles .""
post.  I hadn't  read that because it was part of a series attacking a FairVote page that 
in turn was purporting to debunk a version of your paper that you had announced was soon
to be superseded. Now that I know that you agree with it and that it fully applies to the 
newest version of your paper, I'll get around to studying it and responding.

http://lists.electorama.com/pipermail/election-methods-electorama.com/2008-June/021745.html

BTW, you are in point of fact, incorrect that some voting methods do
not meet Arrow's "independence of alternatives" condition, that is
unless, like Arrow, you are excluding all rating voting methods like
range and approval voting.  If I am wrong in this, then you will be
able to provide an example using the range or approval voting method
which does not meet this Arrows' condition that "the introduction of a
nonwinning candidate changes the outcome of who wins", not merely make
the claim without any supporting example.
Ok. Suppose  the method is Approval, there are two candidates (A and B) and the voters'
utilities (sincere ratings on some fixed scale independent of the candidates) are:
40: A100, B98
25: A98,   B1
35: B100, A1

I assume that with just 2 candidates, all voters will simply approve the one they prefer to
the other, to give the Approval result:
65: A
35: B
A wins. Now suppose that a third candidate (C) is introduced, and including this extra
candidate the voters'  utilities are:


40: A100, B98, C1
25: C100, A98, B1
35: B100, C98, A1
Now all the voters have one candidate they like very much, another they like nearly as much, 
and one they like very much less.  The voters best zero-information strategy is to all approve  2 
candidates, to give the Approval ballots:
40: AB
25: CA
35: BC
I assume that you (Kathy) agrees that this is a reasonable way for these voters to vote,
because this is the Approval election in Appendix A (example 2) in your paper, with the
voters having the same sincere rankings.

Now B wins. IIA says that the winner must either remain A or change to the new 
candidate C.

You can say that Approval meets IIA if you assume that the voted approvals in the 2
candidate election are absolute (by some fixed standard independent of the candidates)
so that the entry of a new candidate can have no effect on the voters' approval or non-approval
of the original candidates.

BTW, I think the particular chosen "wording" of IIA is a sophist attempt to make Approval
and Range's alleged meeting of it look more plausible.  I think it is also supposed to go
the other way as well, i.e. dropping a non-winning candidate shouldn't change the result.
On the  "cast ballots" Approval meets this. It means if we work my example backwards and
go from  3 candidates to 2, then after dropping C we get these Approval ballots:
40: AB
25: A
35: B
B still wins, but obviously in practice if we were having a fresh election without C then not
many voters would approve both the candidates.


Chris Benham




Kathy Dopp kathy.dopp at gmail.com 
Fri Jun 20 21:20:05 PDT 2008 


> Date: Fri, 20 Jun 2008 13:29:17 -0700 (PDT)
> From: Chris Benham <cbenhamau at yahoo.com.au>
> Subject: Re: [Election-Methods] RELEASE: Instant Runoff Voting -
> Since I regard? "IRV" (the Alternative Vote,?unlimited strict ranking?"version") as
> one of? the good methods, the best in my judgement of the methods that meet
> Later-no-Harm,?I am encouraged to respond? to Kathy Dopp's anti-IRV propaganda
> piece.
>

Chris,

All of your points have already been addressed in my paper or by Abd
ul Rahman Lomax on this list.

For example, re "later no harm":

"Later-No-Harm", that a lower preference cannot harm a higher
preference, is FairVote's favorite election criterion.

"Later-No-Harm", however, is incompatible with the basic principles of
majority rule, which requires compromise if decisions are to be made.
That's because the peculiar design of sequential elimination
guarantees -- if a majority is not required -- that a lower preference
cannot harm a higher preference, because the lower preferences are
only considered if a higher one is eliminated. But many think that
later-no-harm is undesirable because it interferes with the process of
equitable compromise that is essential to the social cooperation that
voting is supposed to facilitate. If I am negotiating with my
neighbor, and his preferred option differs from mine, if I reveal that
some compromise option is acceptable to me, before I'm certain that my
favorite won't be chosen, then I may "harm" the chance of my favorite
being chosen. If the method my neighbor and I used to help us make the
decision *requires* later-no-harm, it will interfere with the
negotiation process, make it more difficult to find mutually
acceptable solutions. On the other hand, the "harm" in Bucklin method
of counting votes only occurs if your favorite doesn't win by a
majority in the first round.

BTW, you are in point of fact, incorrect that some voting methods do
not meet Arrow's "independence of alternatives" condition, that is
unless, like Arrow, you are excluding all rating voting methods like
range and approval voting.  If I am wrong in this, then you will be
able to provide an example using the range or approval voting method
which does not meet this Arrows' condition that "the introduction of a
nonwinning candidate changes the outcome of who wins", not merely make
the claim without any supporting example.
--

All your questions are either already answered in my paper somewhere
or are deliberately not addressed in my paper because the topic of the
paper is restricted to the flaws and benefits of the IRV method and
only touches on other topics only as necessary to provide an overview,
as in the recent appendix supplied by voting system experts.  Please
re-read my paper again and I am certain that you will see this.

Thank you for correcting my grammatical mistake in using "criteria"
where I should have used "criterion".

Cheers,

Kathy Dopp



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