[EM] questions about SF's version of IRV

[Bart Ingles]

Dave Ketchum wrote:
> 
> To demand ranking all the candidates has to be UNACCEPTABLE - think of the
> CA recall election and how many candidates they had for governor.  Also
> think of the many voters who are not going to do useful thinking beyond
> bullet voting much as they would do in Plurality.

But that's exactly what's required for some Australian elections.  So
it's not an unreasonable question.  Although the original was also about
voters being *permitted* to rank more than three choices.


> Thus, when IRV promoters talk of "majority" they are NOT thinking of 51+
> percent - they are using this label for their winner, while not talking of
> percents.

True-- it really means "majority of voters expressing a preference for
one of the last two candidates standing."


> Assume 10 voters bullet vote:  4A, 3B, & 3C;  A wins, and I believe they
> claim their winner ALWAYS has a majority.

At least in that case, they can claim (with partial validity) that the
voters with exhausted ballots voluntarily abstained, and therefore
shouldn't be counted as part of the denominator.  But by limiting the
number of candidates that can be ranked, they forfeit even that claim.


> > So with a ten candidate field, the "majority" winner would be preferred
> > head-to-head over at least one other candidate (even though the
> > remaining eight candidates may have head-to-head majorities over the IRV
> > winner).
> >
> > But if you limit the choices to three, then even this limited definition
> > only works for four or fewer candidates.
> >
> 
> Seems to me IRV does NOT have that much trouble here.
> 
> Assume four competitive candidates - SF voters can rank them all (by not
> ranking the least liked).
> 
> Assume less than four competitive candidates - besides ranking them all as
> above, SF voters can rank some fringe candidates from a selection of up to
> a zillion.
> 
> REMEMBER that, while a few voters may desire to rank long lists, it is
> rare that there will be more than four serious candidates, and neither IRV
> nor Condorcet has trouble with candidates they recognize as fringe.

This may not be true for some municipal elections, where the politics
can be pretty chaotic.  I recall one recent SF Supervisorial race had 13
or 14 candidates.  I'm not sure it's always possible to tell which
candidates are serious (for all I know, I might have considered them all
to be fringe candidates).  

I tend to agree when you are talking about major partisan elections,
though.  That's why I have been arguing lately that unless the method
overcomes the Duverger effect, there's really no need to rank more than
one.  Everybody knows which are the top two; anyone who votes for a
third candidate is in effect voluntarily abstaining.

Bart