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<TITLE>Re: [Condorcet] Comment on DMC</TITLE>
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<DIV id=idOWAReplyText8384 dir=ltr>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2>Here's something I posted
today on the Condorcet list.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>Forest</FONT></DIV></DIV>
<DIV dir=ltr><BR>
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<FONT face=Tahoma size=2><B>From:</B> Simmons, Forest <BR><B>Sent:</B> Tue
8/30/2005 1:36 PM<BR><B>To:</B> Condorcet@yahoogroups.com<BR><B>Subject:</B>
Recent History Perspective on Condorcet Methods<BR></FONT><BR></DIV>
<DIV>
<DIV id=idOWAReplyText28709 dir=ltr>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2>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.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>The Condorcet proponents on the EM listserv
have gone round and round on these issues, while never coming to a concensus on
them.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>This fact would seem to resolve the
controversy unless it turned out that total approval was not a good way to
measure defeat strength.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>Therefore, I suggest that we adopt
MinMax(Total Approval) as the Condorcet proposal.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>In my opinion the main questions that
remain are</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>(1) ballot style</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>(2) how best to describe the method
and sell it.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>(3) including which of its many names
to use.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>Of all the names, I think that DMC is the
best!</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>Forest</FONT></DIV></DIV>
<DIV dir=ltr><FONT size=2></FONT> </DIV></DIV>
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