[EM] new working paper: "Four Condorcet-Hare hybrid methods for single-winner elections"

[James Green-Armytage]

Dear Election Methods Fans,

I've been working on a paper entitled "Four Condorcet-Hare hybrid methods for single-winner elections", which I'd like to submit to Voting Matters sometime in the near future, and I'd really appreciate your comments and feedback. 

Here is a link to the current draft:
http://www.econ.ucsb.edu/~armytage/hybrids.pdf

Here is the abstract:
I examine four single-winner election methods, denoted here as Woodall, Benham, Tideman, and Smith-Hare, which each make use of both Condorcet?s pairwise comparison principle and the plurality elimination principle used in Hare?s single transferable vote system. I find that these methods have many significant properties in common, including Smith efficiency and relatively strong resistance to strategic manipulation, though they differ slightly with regard to minor criteria such as ?Smith-IIA? and ?mono-add-plump?.

Here are the non-technical definitions for the four methods:

Woodall
Score candidates according to the Hare (IRV) elimination order, and chose the Smith set candidate with best score. 
That is, define each candidate?s Hare score as the round in which he is eliminated by the Hare method. (The Hare winner is not eliminated, so we set his score to the number of candidates.) If the Smith set has only one member, then this is the Woodall winner; otherwise, the winner is the candidate from inside the Smith set with the best Hare score.

Benham 
Eliminate the plurality loser until there is a Condorcet winner. 
That is, if there is a Condorcet winner, he is also the Woodall winner. Otherwise, the method eliminates the candidate with the fewest first choice votes, and checks to see whether is a candidate who beats all other non-eliminated candidates pairwise. This process repeats until there is such a candidate, who is then declared the winner. 

Smith-Hare  
Eliminate candidates not in the Smith set, and then conduct a Hare tally among remaining candidates.

Tideman
Alternate between eliminating all candidates outside the Smith set, and eliminating the plurality loser, until one candidate remains. 
That is, as in Smith-Hare, we begin by eliminating all candidates outside the Smith set. If this leaves only one candidate (a Condorcet winner), then he is elected. Otherwise, we eliminate the candidate with the fewest first choice votes. Then, we recalculate the Smith set, and eliminate any candidates who were in it before but are no longer in it as a result of the plurality loser elimination. These two steps repeat until only one candidate (the winner) remains.

I do something like a substantially scaled-down version of the analysis from my Strategic Voting and Nomination paper -- the aim is to effectively make the point that these methods are quite resistant to strategy, without letting the analysis take over the whole paper. For those who want more details on the analysis, I suggest the big SVN paper. 

I should also mention that the reason that a few rows in my tables are blank is because I'm still waiting on the results of those simulations.

All right, well, I hope that some of you enjoy the paper, and/or find it informative, and I look forward to your comments. 

my best,
James
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