[Election-Methods] A Better Version of IRV?

[Kristofer Munsterhjelm]

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.