[EM] In political elections C (in terms of serious candidates w. an a priori strong chance of election) will never get large!

[Richard Fobes]

On 5/27/2013 12:19 PM, David L Wetzell wrote:
> ...
> The short-comings of IRV depend on the likely number of serious
> candidates whose a priori odds of winning, before one assigns
> voter-utilities, are strong.  If real life important single-winner
> political elections have economies of scale in running a serious
> election then it's reasonable to expect only 1, 2 or 3 (maybe 4 once in
> a blue moon) candidates to have a priori, no matter what election rule
> gets used, serious chance to win, while the others are at best trying to
> move the center on their key issues and at worse potential spoilers in a
> fptp election.

Plurality voting and limited voting (and the Borda count if the voters 
are undisciplined) are about the only methods that _cannot_ handle 3 or 
(maybe) 4 popular choices along with any number of unpopular choices.

> So it seems disengaged from reality to let C, the number of candidates,
> go to infinity... and if a lot of candidates are not going to get
> elected then to disregard voter info/preference over them is of much
> less consequence.

Although the number of popular candidates is now small, that's because 
we use plurality voting.  When we use better voting methods, the number 
of popular candidates will increase; of course not to infinity, but 
frequently beyond the 3 or 4 popular choices that IRV can handle with 
fairness.

Although it's a non-governmental example, take a look at the current 
VoteFair American Idol poll.  The number of popular music genres is 
about 5, and there are about 7 singers who get more than a few 
first-choice votes.

     http://www.votefair.org/cgi-bin/votefairrank.cgi/votingid=idols

IRV would correctly identify the most popular music genre (based on 
current results), but probably would not correctly identify the most 
popular singer.

Why would voters trust a voting method that stops getting fair results 
with so few popular candidates?

Yes, IRV is easy to explain, but that advantage becomes unimportant as 
the number of popular candidates increases, which it will when better 
voting methods are adopted.

Richard Fobes