[EM] Re: Definite Majority Choice, AWP, AM

[Araucaria Araucana]

Hi Chris,

Nice example.  But there is still a counter-strategic incentive under
DMC -- see below.

On 24 Mar 2005 at 08:11 UTC-0800, Chris Benham wrote:
> Suppose there is pre-polling and so the L supporters
> decide to approve C, while the C supporters sincerely
> divide their approvals.
> Further suppose that the R supporters all decide to
> completely Bury C.  Then we might get:
>
> 49 R>L>>C
> 06 C>R>>L
> 06 C>>R>L
> 06 C>>L>R
> 06 C>L>>R
> 27 L>C>>R
>
> Now all the candidates are in the top cycle: L>C>R>L. 
> The approval scores are  L82,  R55, C51.
>
> Approval Margins:
> L>C  82-51 = +31
> C>R  51-55 =  -4
> R>L  55-82 = -27
>
> AM elects L, backfiring on the Buriers!
> Unfortunately this time DMC eliminates C, and then the
> Buriers' candidate R wins.
>
> Approval-Weighted Pairwise:
> L>C  49
> C>R  45
> R>L  06
>
> AWP gives the same good result as AM!

Yes, with perfect polling knowledge, the R strategy might work.  But
Rock/Paper/Scissors strategy like this doesn't occur in a vacuum.  If
R voters are coordinated enough to bury C in both approval and rank,
they have to operate on the assumption that C>R>L voters might also
suspect something and might all disapprove R instead of splitting.
Without C>R>>L's 6 approval votes, R would be eliminated by the
definitive C>R defeat.  R's ordinal-burial of C would backfire and
elect L.

If I were an R voter, that would be the *last* thing I'd want!

Ted
-- 
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