[EM] 3 or more choices - Condorcet
rbj at audioimagination.com
Sat Sep 29 15:51:53 PDT 2012
On 9/29/12 4:49 PM, Juho Laatu wrote:
> What is a "strong" Condorcet method?
yeah, and Kristofer, since the word is quoted, who is using the label?
i think it might very well be something to agree with (the use of a
really general adjective like "good" or "favorable" or even "optimal"),
i would like to know w.r.t. what? it's like my high school teacher
prohibited us from writing "This book was good" in a book report.
certainly not saying the word is meaningless in context, but it semms
to me meaningless when naked.
but, that said, i still think that a cycle with a Smith set bigger than
3 is soooo unlikely since i still believe that cycles themselves will be
rare in practice. since Minmax, Ranked-pairs, and Schulze all elect the
same candidate in the case of the Smith set of size 1 or 3, it seems to
me that simplicity of tabulation becomes a "strong" property for two
different but related reasons:
1. simplicity is a strong selling point and a necessary one in an
environment of public opposition to "tricky" government procedure.
sometimes complexity in government is unavoidable (how many pages of
text is in a typical bill?) and sometimes the simplest method is clearly
not the best (say, flat income tax rates vs. progressive income tax
rates). but when it comes to seeing how our leaders are elected and how
our miscreants and recalcitrants are dealt with, the public has an
interest in transparency and some of this transparency is mandated in
our national constitutions. but we *do* put up with reasonably complex
regulations and tax codes, we can put up with a teeeny bit of complexity
(the Ranked ballot vs. the "traditional" ballot) in voting.
but the method of tabulation must be reasonably simple for the method to
gain public acceptance and trust. i think most people can understand
the statements: "If more voters prefer Candidate A to Candidate B, then
Candidate B is not elected." and i think that people can understand the
concept that if Candidate A is ranked above Candidate B on their ballot,
this voter would simply vote for A on a traditional ballot if only the
two candidates were running.
selling the additional "burden" of having to commit to and mark their
contingency vote(s) is the challenge, and i usually respond with the
common argument we used in the old IRV days, and it still applies: it is
worth it to collect your (and others) contingency vote because, to get
it later (in a run-off) decreases voter participation and makes the
election less legitimate, particularly if it's close.
2. predictability of operation of a system (like government) is pretty
useful to people affected by the system. we want cars and other
vehicles to behave consistently so that when someone pushes the lever,
the system moves in the direction they intend it to. it may not move
the system sufficiently to accomplish their goal, but it doesn't move
the system directly away from their intended direction. in a modern,
free, and decent society we need consistent laws and proceedures to have
some idea what to expect and what is expected of us. capriciousness or
"flakiness" is a quality to avoid. now when this happens, it's good in
its own right (because it's fair and likely more ethical) but it also
provides more for public acceptance because the rules are clear.
lastly, i know is anecdotal, but the Burlington 2009 IRV election really
bolsters my confidence in cycles being rare (and then cycles bigger than
3 being even more rare). it was a close election. one candidate was
the Plurality winner, one candidate was the IRV winner, and one
candidate was the Condorcet winner. all three candidates were viable
players and there was a fourth, independent, candidate that had a lot of
support but was the first to be eliminated. but when ordered by
Condercet, it is clear who is consistently preferred over everyone else.
remove the CW and it is clear who comes in next. remove the 2nd-place
CW and it is clear who came in 3rd. it was very consistent and nothing
would change if various candidates were removed from the roster and the
same voters came and vote (ranked) identically in another election. no
spoiler scenario in any manner. and that was a close election.
maybe, once in a blue moon, there will be a cycle involving Candidates
Rock, Paper, and Scissors, and then Ranked-Pairs, which is simple, will
do just as well as Schulze.
Markus, i think Schulze would work better for bigger Smith sets, but i
still think it's harder to sell for multip-party, multi-candidate,
governmental elections. and since, i believe it would likely never make
a difference, i would advocate ranked-pairs. i know you sent me that
one paragraph language for possible legislation, but it surely read
opaquely when i read it. i couldn't figure it out from that concise
language (but i think i *do* understand how Schulze based on margins works).
r b-j rbj at audioimagination.com
"Imagination is more important than knowledge."
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