[EM] The "Turkey" problem (to Dave)

[Bart Ingles]

Bart Ingles wrote:
> 
> Dave Ketchum wrote:
> >
> > Coming back to "universally disliked", if this label is true this
> > candidate is not going to get ranked high by enough voters to win.
> >
> 
>        Liked <-----------------------> Disliked
> votes ------------------------------------------
> 49%   A                                    B   C
>  2%   B      A                                 C
> 49%   C                                    B   A
> 
> You could call this a "King Solomon" example, in that since A and C
> can't agree on a winner, someone unacceptable to either wins.
> 
> Another way to look at this is to think of the weaker B>C and B>A
> preferences as "noise", and the stronger preferences as "signal".
> Condorcet amplifies the noise (or clips the signal) so that all have the
> same weight.  I don't know about you, but I can usually stomach having
> my own major preferences overruled by a larger faction's major
> preferences, but would find it a bit sickening to have my major
> preferences overruled by someone else's "noise".
> 
> Kevin Venzke wrote:
> >
> > One of the main things I was arguing was that truncation doesn't benefit
> > the voter who does it (at least in cases where there is a CW).
> 
> Not entirely true, although this involves a prisoner's dilemma.
> 
> If, in advance of the election, the vote count is not known, but A and C
> are believed equally likely to win in a head-to-head contest, the A and
> C factions can agree to truncate and block B from winning, thereby
> giving A and C each a 50% chance of winning.  This increases the
> expected utility of the outcome for both A and C, if B was a likely
> winner on fully-ranked ballots.
> 
> Some believe a prisoner's dilemma strategy to be unworkable, since
> either side can "cheat" the other by failing to truncate, but the cost
> of being cheated seems low in this case.  If nothing else, it seems like
> a bit of a dilemma to decide how to play the prisoner's dilemma.