[EM] FW: Recent History Perspective on Condorcet Methods

[Simmons, Forest]

Here's something I posted today on the Condorcet list.
 
Forest

________________________________

From: Simmons, Forest 
Sent: Tue 8/30/2005 1:36 PM
To: Condorcet at yahoogroups.com
Subject: Recent History Perspective on Condorcet Methods


As most of you know, the Election Methods group has been at the forefront of promoting both Condorcet and Approval for the past ten years.  I have followed it fairly closely for the past five years.
 
The main serious Condorcet proposals over the past ten years have been Beatpath, Ranked Pairs, and MinMax which I have listed in increasing order of simplicity and decreasing order of performance.  More recently we could insert River between Ranked Pairs and MinMax.  The paradox remains; simplicity and performance are diametrically opposed.
 
To make matters worse, there has always been an unresolved controversy over whether it is better to measure defeat strength (a concept used by all four methods) in terms of margins or winning votes.
 
The Condorcet proponents on the EM listserv have gone round and round on these issues, while never coming to a concensus on them.
 
However, recently Jobst showed that if one measures defeat strength by total approval (of the victor in the pairwise defeat) then all four of these competing methods coalesce into one method.
 
This fact would seem to resolve the controversy unless it turned out that total approval was not a good way to measure defeat strength.
 
However, it seems to be better than winning votes or margins.  The defensive properties of winning votes that are normally obtained by "defensive truncation" can usually (if not always) be obtained by raising the approval cutoff instead of truncating the rankings.
 
Therefore, I suggest that we adopt MinMax(Total Approval) as the Condorcet proposal.
 
In my opinion the main questions that remain are
 
(1)  ballot style
 
(2)  how best to describe the method and sell it.
 
(3)  including which of its many names to use.
 
Of all the names, I think that DMC is the best!
 
Forest
 
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