[EM] IRV vs RCV

[robert bristow-johnson]

> On December 14, 2019 2:44 AM Rob Lanphier <robla at robla.net> wrote:
> 
>  
> On Fri, Dec 13, 2019 at 9:21 PM robert bristow-johnson
> <rbj at audioimagination.com> wrote:
> > but things are hard to change with election law.  while i like Ranked Pairs (using margins) better, i can see value in BTR-STV as a means to get a Condorcet-compliant method adopted as law.  We can say to the followers of FairVote that it's IRV with rounds.  And we can say it fixes the problem of risk of not electing the Condorcet candidate (if there is one).  it's Condorcet-compliant IRV and i wouldn't mind if they called that "RCV".
> 
> Yeah, I totally agree with all of this.  I also like Ranked Pairs, but
> I suspect that all of the methods that pick a candidate out of the
> Smith set are indistinguishable in real-world conditions.  My hunch is
> that an analysis of the public elections that had ranked ballots would
> reveal that all of them had a single Condorcet winner,

except, of course, Burlington Vermont 2009.

> and therefore
> there would be no difference between the results of Ranked Pairs,
> Schulze, Tideman, Schulze, or even Copeland.

this is the difficult point i have tried to say here.  i think that Schulze is likely the most resistant to voting strategy, but it's too difficult to explain to legislators and the public.

BTR-STV is different.  Schulze, RP, MinMax (dunno about Copeland) all elect the same candidate in the case of an CW or a Smith set of 3.  i don't ever ever ever expect to see a Condorcet RCV ever have a Smith set larger than and i really don't expect to see one without a CW.

>  So BTR-STV seems like a
> fine compromise, since IRV has failed to pick the Condorcet winner in
> at least one recent public election.

yes, and i am trying to remind the Progs of that.  but they are not listening.

--
 
r b-j                  rbj at audioimagination.com
 
"Imagination is more important than knowledge."