Juho wrote:
On Mar 10, 2010, at 7:08 AM, robert bristow-johnson wrote:
so, keeping RP, Schulze in mind for later, what would be a "good"
scheme for resolving cycles by use of elimination of candidates? what
would be a "good" (that is resistant to more anomalies) and simple
method to identify the "weakest candidate" (in the Smith set) to
eliminate and run the beats-all tabulation again? i'm not saying
elimination is a good way to do it, but it might be easier to sell to
neanderthal voters.
All methods have some weaknesses that can be used against them in the
marketing battle. So maybe the challenge is to build a solid campaign
that is convincing enough to neutralize all emerging fears and failure
examples.
Schulze method is quite convincing since it is already in use in many
places. (I'm not sure it is objectively better than ranked pairs and
others although it is certainly a good method.) Ranked pairs can be
easily described as a method that sequentially confirms pairwise wins,
so it is almost as natural and straight forward sequential algorithm
based as IRV (although it is a bit more complex in the sense that it
compares pairs instead of single candidates when making the sequential
decisions). And there are also simpler Condorcet methods like
minmax(margins) that simply counts the number of additional votes each
candidate would need to beat all others.
For Schulze, I think the strategy should make use of its current
popularity (relative to other Condorcet methods, at least). Maybe make
Condorcet programs and patches to widen its use among those who know
computers, and encourage organizations to use Schulze for their internal
decisions (like the Pirate Party did with its primaries, although that's
not quite the ideal usage of the system).
I'm not aware of any sequential candidate elimination based method that
I'd be happy to recommend. One can however describe e.g. minmax(margins)
in that way. Eliminate the candidate that is worst in the sense that it
would need most additional votes to win others, then the next etc. In
the elimination process one would consider also losses to candidates
that have already been eliminated (I wonder if this approach makes it
less "natural looking" than the elimination process of IRV).
To my knowledge, Schulze-elimination is the same as basic Schulze. In
other words, if you run Schulze, eliminate the loser, run it again, etc,
you end up with the original result. That's not very useful, but still...
It might also be that any "full-blown candidate elimination method" (you
run the election as if the one that was eliminated never stood) with a
weighted positional base method (Borda, Plurality, ...) is nonmonotonic.
I can't prove it though!
But as said, maybe the key is to arrange a solid campaign. You can
surely e.g. find lots of election method experts that are happy to agree
that Condorcet methods are the best for some city for some need and best
single winner methods (for competitive elections) in general. But quite
certainly there will be also experts that think otherwise. And there is
certainly a risk that all the Condorcet friendly experts will use
different argumentation, may disagree on details and as a result will
confuse the audience. Maybe one should start from Scientific American
etc. to first firmly establish the idea that Condorcet methods indeed
are the de facto state of art methods (and practical too). IRV campaigns
have been successful, so I wonder why Condorcet campaigns could not
follow (maybe Burlington needs a timeout now but not much more, and
other cities could take steps forward already now and support Burlington
that way).
The first step would be to say: okay, there are many Condorcet methods,
but they differ in fine tuning. For public elections, good enough is
good enough, and let's pick one that's good, then unify around it. That
method could be RP or it could be Schulze, or something else (I think
independence from Pareto-dominated alternatives would be nice, but at
some point we'll just have to say "good enough").
I mention RP and Schulze in particular because RP is easy to explain
(relatively, given the criteria it passes), and Schulze has some record
of use.
So does, say, Copeland, but in my opinion, it isn't "good enough". The
iterated Copeland(2,1) version may be better, but probably isn't
cloneproof.. and so on.
(I have to add that if people want to keep the USA as it mostly is, a
two party based system, then I must recommend FPTP :-). And if not, then
maybe also some additional (maybe proportionality related) reforms are
needed.)
Wouldn't something like Condorcet multiwinner districts be better? Pick
a good Condorcet method and send the 5 first ranked on its social
ordering to the legislature. That would pick a bunch of centrists (thus
have "stability"), but it would pick the centrists people actually wanted.
Hm, that might not provide a true two-party system, though. One could
also have a "PR" system where the number of votes is weighted so that
parties with broad support gain superproportional power, but then the
question becomes why one should bother with the PR at all.
----
Election-Methods mailing list - see http://electorama.com/em for list info
