[EM] Dave Ketchum: IRV strategy

[MIKE OSSIPOFF]

Dave:

On Dec 6, 2011, at 4:19 PM, MIKE OSSIPOFF wrote:
>
>
> How to vote in IRV:
>
>
>
> When there are completely unacceptable candidates who might
> win (I call that condition u/a, for “unacceptable/acceptable”)
 
You replied:

You DO NOT rank such since, if you rank such a candidate, so might  
enough others for this one to win - you do not want to be part of  
causing such a win.

[endquote]

But your vote won't reach the candidates whom you consider unacceptable 
unless and until all of the acceptable candidates have been eliminated.
So, by that time, it's no longer a question of _whether_ an unacceptable
will win. It's only a question of _which_ unacceptable will win.

But of course it's vastly more important to elect an acceptable vs
determining which unacceptable wins. Still, if you have time, then
you might as well rank the unacceptables too, so that, at least,
the _worst_ ones won't win.



>
>
> IRV, like many methods, has a relatively simple strategy:
>
>
>
> Rank the acceptable candidates in order of (some guessed or
> complicatedly-calculated measure of) their popularity.
 
Rank in the order of what YOU see as should be most popular first.
 

[endquote]

Yes--You must guess which acceptable is most likely to be helped to win
by your top ranking. And then, which of the remaining acceptables is most
likely to be helped to win by your 2nd-place ranking...etc.


> Ideally, then rank the unacceptables in order of some
> complicated combination of their disutility and
> (some guessed or complicatedly-calculated measure of) their  
> popularity.
>
>
>
> Actually, ignore that last paragraph. In u/a, all the
> unacceptables are just unacceptable. What matters is the election of  
> an
> acceptable instead of an unacceptable.
>
>
>
> In u/a, IRV is just ranked Plurality. In Plurality you vote
> for the acceptable candidate who is most popular (most likely to get  
> the most
> votes).
 
Read that carefully.  You do not vote for unacceptable here

[endquote]

Quite so. You never vote for an unacceptable in Plurality

...unless you're a Democrat-voting progressive  :-)

But you shouldn't.

Vote for the acceptable most likely to be helped to win by your vote.
...the acceptable most likely to be the best votegetter among the
acceptables.

Mike Ossipoff