On Jul 12, 2008, at 17:56 , Kristofer Munsterhjelm wrote:
Dave Ketchum wrote:
Again, why NOT Condorcet?
Its' ballot is ranking, essentially the same as IRV, except the
directions better be more intelligent:
Rank as many as you choose - ranking all is acceptable IF you
choose.
Rank as few as you choose - bullet voting is acceptable if
that completes a voter's desired expression.
Equal ranking permitted.
Condorcet usually awards the same winner as IRV. Major differences:
Condorcet looks at ALL that the voters rank, while IRV
ignores parts.
Condorcet recognizes near ties, and tries to respond
accordingly.
Could be a debate about the near ties - would it be better to
resolve such with a runoff? Runoffs take time and are expensive.
Are they enough better than what Condorcet can do with the
original vote counts?
On technical merit alone, why not Condorcet indeed? But the thread
was about momentum. In the situation where IRV can't be stopped,
what is the best way to nudge IRV towards something more desirable
while still keeping it IRV-ish enough that it'll retain the
momentum of "pure IRV"?
One very simple approach would be to promote ranked methods as one
group. Just join the bandwagon, include all methods and leave the
details of the method to be decided later (pick the best then). The
delta from plurality to ranked methods and achieved improvements are
clear.
One modification that's been mentioned before is bottom two runoff
- eliminate the one of the two last placed that fewer prefer to the
other. That would ensure a Condorcet winner always wins, but to
core IRV supporters, that's a weakness, because the Condorcet
winner could be a weak centrist. The ameliorated procedure would
also fail LNHarm.
If the people on which the momentum is based would support any sort
of elimination procedure, then I think Borda-elimination would be
better; so what one really has to ask is, if IRV is unstoppable,
then how far from pure IRV can you go and still have it be IRV? IRV
with candidate withdrawal? IRV with candidate completion? BTR-IRV?
Schwartz,IRV? Any sort of elimination system? Any sort of ranked
ballot system?
One argument against Condorcet, which one may call half-technical,
is complexity. It's technical because it regards the method itself
and not whether Condorcet Winners are good winners (or similar),
and nontechnical because what's complex to a computer may not be
complex to a person and vice versa.
As far as complexity with regards to Condorcet goes, the good
Condorcet methods are complex. Schulze may be easy to program (once
you know the beatpath algorithm), but explaining beatpaths to the
average voter is going to be hard. Copeland is easy but not very
good and ties a lot.
Some Condorcet methods are simple, like minmax. It is good too. I
note that you later referred to cloneproof methods as good methods.
Minmax is not fully cloneproof but I don't think that is a problem.
(Same with not being fully Condorcet loser compliant.)
If your favourite Condorcet method is complex then it may better
start with promoting Condorcet methods in general. I think it is in
any case a mistake to dive into the details of the methods when
promoting an electoral reform. Citizens and politicians are simply
not interested in such dives (would be counterproductive). Better to
use some more general arguments that are linked to the reform needs
at more general level.
One thing I've observed is that IRV focuses on how the process is
done, while Condorcet methods focus on properties ("the winner is
the candidate which wins all one-on-one contests"). I'd say
explaining properties would be more easily understood than
explaining the process, but apparently this isn't a great
limitation for IRV, given its momentum so far.
IRV is typically described as it it was a "public fight" between
candidates where the candidates are eliminated one at a time. This is
a very appealing style because of the very real life like and exiting
image it offers. The description also sounds quite fair (at least at
first sight).
There are also differences in how different Condorcet methods are
described. To me methods that are justified using (possibly long)
beat paths are philosophically different from methods that are based
on evaluating the more local properties of individual candidates
(e.g. minmax).
(Also the philosophy of finding a complete ordering of the candidates
is different from the philosophy of just identifying the best
candidate without establishing a complete order. The interesting
point is that individual preferences of the voters are usually
expected to linear while it is known that group opinions may well be
cyclic (just a natural property, not a fault that should be somehow
corrected).)
Perhaps Ranked Pairs would have a chance? It's one of the better
Condorcet methods (cloneproof, etc), and if people accept the
pairwise comparison idea, it should follow quite easily. Say
something like that you can't please everyone all the time, so
please most, which is to say that one locks preferences in the
order of greatest victories first. Then anyone complaining because
his group's (cyclic) preference was not locked could be rebutted by
a larger group saying that if it had been, more people (namely,
that larger group) would have been overridden. Here you have both
method (locking) and properties (group complaint "immunity"), as well.
It'd be interesting to investigate which simple or intuitive
methods are the best. I don't know what would constitute simple to
voters, perhaps "Of those candidates that [some statement], choose
the one that [some statement]", or "[Somehow reduce the set of
candidates] until [criterion is met], then that one is the winner"
for various sentence parts inside the brackets. Those are all
method-based explanations; maybe property-based ones would be
better. If the voter trusts that the method does what the property
says, and the property is desirable, then that could be the case.
I'll continue my "minmax campaign" a bit more. The best part of minmax
(margins) (and the reason why I'm interested in it) is that it has a
very natural (and easy to understand) description and justification.
It elects the candidate that needs the least number of additional
votes (if any) to win each of the other candidates (in pairwise
comparisons). I'd say that is a reasonably good description of a
candidate that deserves to win (if one is looking for a good
compromise candidate).
Juho
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