[EM] ruminations on ordinal and cardinal information

[James Green-Armytage]

James G-A replying to Russ 
>
>My first comment is that this proposal is significantly more complicated 
>than my (or Kevin's) "Ranked Approval Voting" (RAV) proposal, which 
>simply drops the least approved candidate until a CW is found.

	Yes, I suppose the tally is harder to explain, although the interface is
identical. However, you've not responded to the points I made in the last
e-mail about strategic vulnerability in your RAV method.
http://lists.electorama.com/pipermail/election-methods-electorama.com/2005-March/015226.html
>
>Secondly, I find it interesting that you define the magnitude of a 
>defeat in step 3 as, "the number of voters who place A above their 
>approval cutoff and B below their approval cutoff." This is equivalent 
>to using the difference of Approval scores for the two candidates (with 
>a constant offset). 

	No, it isn't. You can have a very strong defeat even when a candidate
with a higher approval score beats a candidate with a lower approval
score. You seem to be imagining that I wrote "the number of voters who
place A above their 
approval cutoff and B below it, ***minus the number of voters who place B
above their approval cutoff and A below it***." But the second part of
that sentence isn't in my proposal. This creates a world of difference,
and that difference has important anti-strategic properties. Again, I urge
you to read the cardinal pairwise paper and the strategy example posting. 
http://fc.antioch.edu/~james_green-armytage/cwp13.htm
http://lists.electorama.com/pipermail/election-methods-electorama.com/2004-September/013936.html

>If you simply used the winning approval score rather 
>than the difference, I think your proposal would be equivalent to RAV.

	I don't use the difference.
>
>Elsewhere you have advocated using "winning votes" rather than "margins" 
>for the pairwise measure off Condorcet defeat magnitude, but here you 
>seem to be advocating "margins" for the defeat magnitude when it is 
>based on approval scores. Why the difference? What is the advantage of 
>using "margins" in your proposal? 

	This is exactly where you are misunderstanding my proposal. Cardinal
pairwise and approval-weighted pairwise both use winning rating
differentials rather than marginal rating differentials. That's what makes
these methods interesting. Please read the references I give you.

>More importantly, does the advantage, 
>if there is one, justify the additional complexity of your proposal? I 
>must tell you that I'll be surprised if it does. Then again, it won't be 
>the first time I've been surprised.

	Yes, the benefits do justify the additional subtlety of the method.
Because approval-weighted pairwise is more strategy resistant than RAV.
>
Sincerely,
James
http://fc.antioch.edu/~james_green-armytage/voting.htm