On 11/8/12 11:55 AM, Chris Benham wrote:
Robert Bristow-Johnson wrote (1 Oct 2012):
"my spin is similar. Ranked Pairs simply says that some "elections" (or
"runoffs") speak more loudly than others. those with higher margins are
more definitive in expressing the will of the electorate than elections
with small margins. of course, a margin of zero is a tie and this says
*nothing* regarding the will of the electorate, since it can go either
way.
the reason i like margins over winning votes is that the margin, in vote
count, is the product of the margin as a percent (that would be a
measure of the decisiveness of the electorate) times the total number of
votes (which is a measure of how important the election is). so the
margin in votes is the product of salience of the race times how
decisive the decision is."
Say there are 3 candidates and the voters have the option to fully
rank them,
but instead they all just choose to vote FPP-style thus:
49: A
48: B
03: C
Of course the only possible winner is A. Now say the election is held
again (with
the same voters and candidates), and the B voters change to B>C giving:
49: A
48: B>C
03: C
Now to my mind this change adds strength to no candidate other
than C, so the winner
should either stay the same or change to C. Does anyone disagree?
So how do you (Robert or whoever the cap fits) justify to the A voters
(and any fair-minded
person not infatuated with the Margins pairwise algorithm) that the
new Margins winner is B??
The pairwise comparisons: B>C 48-3, C>A 51-49, A>B 49-48.
Ranked Pairs(Margins) gives the order B>C>A.
I am happy with either A or C winning, but a win for C might look odd
to people accustomed
to FPP and/or IRV.
*If* we insist on a Condorcet method that uses only information
contained in the pairwise
matrix (and so ignoring all positional or "approval" information) then
*maybe* "Losing Votes"
is the best way to weigh the pairwise results. (So the strongest
pairwise results are those where
the loser has the fewest votes and, put the other way, the weakest
results are those where the
loser gets the most votes).
In the example Losing Votes elects A. Winning Votes elects C which I'm
fine with, but I don't
like Winning Votes for other reasons.
well, i'm not the guy with upper-case letters. i didn't comment on this
response to what i said, but looking it over right now, whether people
vote on a Ranked-Choice ballot as if it were FPP or not, any candidates
*not* ranked are tied for last place on that ballot. so
49: A
48: B
03: C
is really
49: A>B A>C
48: B>A B>C
03: C>A C>B
the difference with this:
49: A
48: B>C
03: C
is that C gets a helluva lot more support from B voters than the other
scenario.
49: A>B A>C
48: B>C>A
03: C>A C>B
it's the same old complaint that Rob Ritchie (FairVote) and others make
against Condorcet (justifying putting all their support behind IRV):
that (from their POV) Condorcet can elect wishy-washy candidates with
little primary support. i (and Condorcet) would say that in the second
case, C is the best candidate even if he/she got only 3 first-choice
votes. might be a nice centrist, no-drama candidate in a polarized
environment. in Burlington VT 2009, the 3rd-place finisher from the POV
or FPP or IRV was the Condorcet winner and nearly everyone i talked with
would have been much happier with this candidate than with whom actually
won the IRV or with whom would have won FPP (who suffered a decisive
defeat in a repeat run in March 2012). but the margins weren't so wide
as with this example, candidate C got a lot more than 3% primary support
votes.
again, i will repeat that probably, technically, Schulze is superior to
Ranked-Pairs. but it doesn't matter with a Smith Set of 3 candidates or
less. Condorcet cycles will be rare. cycles with more than 3 in the
Smith set will be rare of the rare. it's best to get Condorcet of
*some* method enacted into law. the most realistic path to
accomplishing that is *not* to advocate a method that cannot be
explained to citizen-legislators. and i still think that margins is
better than either winning votes (or the logical complement regarding
the most losing votes). margins encompasses *both* winning votes and
losing votes (the latter with a negative sign, of course).
--
r b-j r...@audioimagination.com
"Imagination is more important than knowledge."
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