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 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.
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.
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.
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