[EM] bullet voting and strategy on Approval ballots.

[Kristofer Munsterhjelm]

>>> and i don't quite get whether a bunch of people bullet voted in the
>> Burlington IRV elections has much to do with the Approval or Score.
> 
> some people chose to bullet vote on the ranked-order ballot in the two 
> IRV elections we had in Burlington VT.  that bullet voting was not 
> necessary (or should not have been necessary) in order to prevent harm 
> to their favorite candidate, assuming that was the candidate they bulleted.
> 
> on the other hand, Approval and Score *does* potentially harm your 
> favorite unless you bullet your favorite.  if a large component of 
> people bullet vote their favorite in Approval or Score, the outcome of 
> the election is not any different than it would be for Plurality.

I think Approval is limited in some ways, particularly how it 
"externalizes strategy" in my terms (moves strategy out of the method 
itself, thus it is able to pass a lot of criteria that it might not if 
everybody strategized). However, hurting your favorite doesn't seem to 
be one of the problems of Approval.

Consider this. If you vote for the lesser of the two evils (according to 
poll data), then you can't possibly harm this lesser of two evils if you 
also approve all the candidates that you prefer to him. The only thing 
that can do is shift the election *away* from the lesser evil onto 
someone you like better. Therefore, if you're going to bullet-vote, you 
can at least vote for those you prefer to the candidate in question.

That leaves the option of bullet-voting for your favorite. In what case 
could voting for someone lesser than your favorite hurt you? That could 
happen in the case where there are multiple candidates and all are 
relatively strong. Say that you have Nader, Gore, and Bush, but this is 
an alternate reality where Nader is rather strong (perhaps because of 
Approval voting). Then if all the Nader-votes err towards safety and say 
{Nader+Gore}, Nader is not going to win, because Gore will get at least 
as many votes as Nader; but if that is the case, polls will show Gore to 
be even stronger and thus the Nader-voters know to vote Nader alone.

Thus it would seem to me that you only need to bullet-vote when your 
favorite is strong. Otherwise you can vote for your favored "strong" 
candidate and all candidates you prefer to him. The need for this poll 
data is, in my opinion, a problem of Approval (and makes the 
consideration of honest Approval a bit of a distraction), but it is 
better than Plurality - you only have to bullet-vote if the situation is 
already very different than in Plurality, not all the time as Plurality 
forces you to.