[EM] Weighted Pairwise

[James Green-Armytage]

This is James Green-Armytage replying to Mike Ossipoff.

Prescript: I recently started calling my method "cardinal pairwise"
instead of "weighted pairwise" for short. The full name is
"cardinal-weighted pairwise comparison," so really, either abbreviation is
appropriate. I just don't want you to be confused when I call it "cardinal
pairwise" in this posting, or later on... Sorry about the switcheroo, I
just thought that maybe "cardinal pairwise" was more descriptive. Feel
free to use the other name if you prefer that.

Mike, you wrote:
>
>Sure, Weighted Pairwise, from what you've said, seems to improve on the 
>criterion compliances of ordinary wv.

	Well, I think that it helps more with qualitative criteria than yes/no
criteria, in particular, resistance to severe strategic manipulation. Also
I think that the extra level of expressiveness (the ratings ballot) is a
good thing, and makes for more-meaningful resolution of sincere cycles. I
suppose that you could make yes/no criteria out of some of these things,
but I'm not sure that they would be able to completely encapsulate the
benefits of cardinal pairwise. 

you wrote:
>
>I haven't thoroughly compared WP to ordinary wv with AERLO & ATLO. WP may 
>not offer the strategy improvements of AERLO & ATLO.

	I doubt that ATLO and AERLO will be as effectively and easily
strategy-resistant as cardinal pairwise, but I'd be open to further
discussion on the matter. I ask that you please read the latest version of
my cardinal pairwise paper before engaging me in discussion about the
method's counter-strategic properties, because the paper goes into great
detail on the topic. Frankly, I didn't really understand cardinal
pairwise's strategic properties very well myself until I started gathering
my thoughts to write that paper; when analyzing it in depth, I found some
things that I did not expect to find. You can read the paper via either
one of these links, which are the "Voting Matters" version, and my own
version, respectively.
http://www.mcdougall.org.uk/VM/ISSUE19/I19P2.PDF
http://fc.antioch.edu/~james_green-armytage/cwp13.pdf
	So, rather than asking whether cardinal pairwise provides the same
resistance to strategy as AERLO and ATLO, I'd like to ask whether AERLO
and ATLO provide the same resistance as cardinal pairwise. Also, I believe
that cardinal pairwise achieves many of its counterstrategic benefits
without any need for conscious counterstrategizing by the voters. Lots of
voters giving Bush a very low rating and Kerry a very high rating makes it
very hard to overrule a Kerry>Bush defeat, but the voters don't all need
to understand majority rule cycles, or anticipate a particular strategic
incursion, in order to guard against an incursion that attempts to
overrule the defeat. The neat thing about cardinal pairwise is that rating
the candidates intuitively is usually a good protection against strategy.
AERLO and ATLO don't have this benefit, because the concept of truncation
lines and equal ranking lines is never going to be as intuitive to voters
as ranking the candidates on a scale from 0 to 100. 

you wrote:
>
>Of course Weighted Pairwise is more complicated than ordinary wv, and so
>an 
>initial Condorcet proposal should probably be ordinary unenhanced wv.
>AERLO 
>& ATLO could then easily be proposed later, as needed, as add-ons.
>If that later proposal were  Weighted Pairwise, a more complicated
>different 
>method, it probably would be more difficult to get acceptance for.

	Yes, I can't avoid the fact that cardinal pairwise is pretty darn
complicated, compared to plurality, compared to IRV, and compared to
regular ranked pairs. I think that I appreciate the absurdity of trying to
convince people to adopt it for presidential elections in the current
political climate, because there is such a strong current of
anti-intellectualism, and it would probably be hard to get most
congresspeople to pay attention for long enough to explain why cardinal
pairwise is a good idea. I guess that it's more of a very-long term
proposal.
	However, in the medium-long term, there is still a question of whether
ordinary winning votes is a good idea for major offices, i.e. president,
governor. I'm not sure that either of us want to go into this issue again
(we've both probably expressed most of our arguments already, and I
remember that we reached a frustrating deadlock on the issue in May of
this year), but my feeling is that the burying strategy might be too big
of a problem in unenhanced WV to use it on this scale. Maybe we can agree
to disagree on that one, and wait until we get more empirical evidence
from Condorcet methods used on a smaller scale. 
	I've been toying with the idea that Condorcet completed by IRV (choosing
from the minimal dominant set) might be slightly more acceptable from this
standpoint, but that has problems too, of course... I guess if that one
turned out to be okay, I would imagine the following progression for
single winner elections:

1. plurality or runoffs 
2. equal-rankings IRV 
3. minimal dominant set completed by IRV.
4. cardinal pairwise??

	I don't know; it seems like something's still missing. What do you think?

you wrote:
>
>Maybe the AERLO & ATLO options, with Weighted Pairwise, would result in
>more 
>improvement than either enhancement by itself.

	I don't know. Maybe. I'll have to think about that one.

my best,
James