[EM] New criterion: The Co-operation/Defection Criterion

[Jameson Quinn]

>
>
> I'm assuming cast ballots look something like this:
>
> 48 C>A
> ~26 A>B
> ~26 B (sincere is B>A)


That looks right. In fact, let's make it more extreme:

39 C
10 C>A
21 A>B
30 B

According to the criterion as stated, A must win this election. But what if
the honest preferences are actually:
21 A>C
10 C>A
39 C>B
30 B>C
The B>C and C>B factions truncated because these two were the frontrunners.
The C>A faction didn't truncate because A, with only 31% support at any
level, was no threat at all. And the A>C faction sneakily voted A>B and
stole the election!

Perhaps this particular scenario is unlikely. But I think that it's nearly
impossible to meet this criterion without opening up some loophole like
this.

Moreover, even without this loophole, I just don't like how that first
election looks. A, with 31 votes total, the lowest of any candidate, wins? I
just can't imagine trying to convince people that that's the right answer.
If there were more than three people in the room, you wouldn't get 5 words
out before they started laughing and interrupting you with sarcasm.

So, the only way to meet this criterion, is to never have the situation
happen in the first place. It sounds impossible. Unless...

(I bet at least a few of you have already guessed what's coming)

... you use SODA voting. With SODA, it's not in candidate B's interest to
truncate, because candidate A might retaliate, and because B voters might
choose not to delegate. And the B voters will hardly make an organized
campaign to all truncate, if just giving a delegated vote to B is easier. I
think that SODA will stop the truncation from happening in the first place;
especially with the extra optional rule which resolves this
case<http://wiki.electorama.com/wiki/SODA_voting#Finish_resolving_the_.22Chicken_Dilemma.22>
.

So I don't like this criterion... but I think that the scenario is an
argument for SODA.

Jameson
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