[EM] Binary dropping of candidates

[robert bristow-johnson]

On Oct 23, 2010, at 6:15 PM, Michael Rouse wrote:

> It's probably already been discussed before (most likely with a more  
> descriptive name), but the election methods list has been quiet, so...
>
> Has anyone looked at making a ranked list  of candidates -- either  
> by number of first place votes, as in IRV, or Borda order, as in  
> Nanson/Baldwin -- and dropping candidates in a binary rather than  
> unary way?
>
> By way of example, in Instant Runoff Voting, you see if a candidate  
> has a majority. If not, you drop the lowest candidate. If there is  
> still no candidate, you drop the next lowest candidate, and so on.  
> With five candidates, you have something like this:
>
> .....   First round (no one dropped)
> ....1 Second round (one person dropped, ballots redistributed)
> ...11 Third round (two people dropped, ballots redistributed)
> ..111 Fourth round (three people dropped, ballots redistributed)
> (for five candidates, three drops are sufficient)
>
> It's a method analogous to a unary counting system.


i don't get it.  how is this different from IRV?  if you're dropping  
them on the basis of number of first place votes, it's IRV.  if it's  
on some other basis, well, it's different in a quantitative way.  if  
it's Bottom-Two-Runoff-IRV, then it's Condorcet compliant.  isn't it  
all IRV, but with different rules for selecting the candidates you keep?

--

r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."