Chris said:
There is group of pairwise methods that use "winning votes" to measure
"defeat strength" that as I understand it always give
the same winner unless there are more than three candidates in a top cycle.
That situation would be very very rare and almost
certainly would never happen in a public political election, so for
practical intents and purposes the differences between them
are insignificant and they are one method.
I reply:
Fair enough. But I like the additional GSFC guarantee that SSD has and PC
doesnt have.
Dave continues:
The most prominent member of this group is Schulze (aka Beatpath), but
others are the Winning Votes versions of Ranked Pairs,
River, and Smith//MinMax. Correct me if I'm wrong, but isn't this all that
you are referring to by "a set of methods"?
I reply:
You left out my favorite one: SSD.
And Plain Condorcet (PC) is a wv method too.
But otherwise, yes that pretty much covers it. But I dont know if
Smith//Minmax meets all 4 of the majority defensive strategy criteria. It
seems to me that Markus once asked me for a demonstration and I couldnt
find one.
By the way,Ive always objected to calling Plain Condorcet MinMax, because
MinMax is used with more than one meaning.
Chris continues:
I meant that I don't think it [BC] is generally useful for the task of
evaluating voting methods, for discerning or discovering
which is/are the best.
I reply:
Of course not, not directly. The 4 majority defensive strategy criteria do
that. BC is only a way of testing for compliance with those 4 majority
defensive strategy criteria.
Chris continues:
Because if someone thinks that it is a big black mark for a method if it
doesn't meet all four of
WDSC, SDSC,SFC, GSFC then their mind is mostly made up.
I reply:
about that, sure. But isnt that true of any conclusion about anything?
And yes, if you dont want a method that fails the 4 majority defensive
strategy criteria, then you could use BC as a quick and easy way to find out
if a method meets them.
Mike Ossipoff
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