[EM] questions about SF's version of IRV

[Dave Ketchum]

On Sat, 01 May 2004 09:50:03 -0700 Bart Ingles wrote:

> 
> 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.
> 

The reference to Australian usage sounds like the kind of reasoning that 
would declare current heavy usage of Plurality to make that method acceptable.

I continue to argue for Condorcet:
      There are many elections in which many of the voters cannot express 
their desires as completely with simpler methods as with ranked ballots.
      There are often only one or two competitive candidates, for which 
demanding that voters participate in more than bullet voting 
produces nothing useful - and can produce destructive noise with no 
usefulness.

> 
> 
>>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."
> 

Which is a misuse of the word.

> 
> 
>>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 concede carelessness in overuse of "serious" - a candidate can be 
applying all of available abilities and get zero votes.  I intended to say 
"competitive" for candidates who attracted enough voter interest to win, 
or at least be near there.

With 14 candidates you may not know which are competitive until you count 
the votes - almost certainly some will have only fringe counts (but I 
would almost never classify all as fringe - I see the winner as 
competitive by definition).


> 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.
> 

BUT:
      You do NOT ALWAYS know which are the top two, or even whether there 
are exactly two at the top, even if you have honest polling.
      We NEED to permit voting for fringe candidates, such as for Nader in 
2000, without this affecting competitive candidates.


> Bart

-- 
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  Dave Ketchum   108 Halstead Ave, Owego, NY  13827-1708   607-687-5026
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