[EM] election strategy paper, alternative Smith, web site relaunch

[James Green-Armytage]

Hello. This is James G-A, responding to the following post by Chris Benham:
http://lists.electorama.com/pipermail/election-methods-electorama.com/2010-November/026954.html

Chris and I have had a good discussion about this since his post,  
which has enabled me to get back up to speed on some of the things he  
mentioned.

So, to summarize, there are at least two distinct approaches to  
creating Smith/Hare hybrid single winner election methods.

One approach is to first eliminate the candidates outside the Smith  
set, and then to hold an IRV tally among remaining candidates. Nic  
Tideman's 'alternative Smith' method is a variation on this, which  
provides for further elimination of extra-Smith candidates in between  
IRV counting rounds.

Another approach is to successively eliminate the plurality loser  
until there is a Condorcet winner among remaining candidates. An  
equivalent method to this is to do an IRV tally, give each candidate a  
score according to the number of candidates eliminated before them,  
and then choose the Smith set candidate with the highest score.  
Douglas Woodall seems to have proposed this in 2003 or earlier, though  
I'm not sure if he has done so in any published forum.

In our discussion, Chris Benham and I resolved that the former  
approach has the advantage of satisfying the 'local IIA' criterion  
(which states that adding a candidate outside the Smith set should not  
affect an election result), while Woodall's approach has the advantage  
of satisfying the 'mono-add-plump' and 'mono-append' criteria (which  
are defined, for example, in Woodall's "Properties of Preferential  
Election Rules", Voting Matters December 1994).

Chris feels that the monotonicity criteria are more important, but I  
remain undecided about that. My conclusion at this point is that  
neither approach entirely dominates the other. One thing that I will  
say in favor of Woodall's approach is that it has the simplest  
definition, which suggests a certain elegance, and which means that it  
would probably be easier to sell to a skeptical public.

I've run a few of my election strategy simulations on Woodall's  
method, and so far I've found no difference between its performance  
and that of the other approach. So, both approaches seem to share  
these three highly desirable properties: (1) Smith efficiency, (2)  
minimal vulnerability to strategic voting, and (3) minimal voting to  
strategic nomination.

In my opinion, this combination is a really big deal, and I look  
forward to further discussion of these methods.

Sincerely,
James