[EM] Chris reply, Feb. 18, 0117 GMT

[Michael Ossipoff]

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 
doesn’t 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 don’t 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 couldn’t 
find one.

By the way,I’ve 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 isn’t that true of any conclusion about anything?

And yes, if you don’t 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