[EM] Just to let you know...

robert bristow-johnson rbj at audioimagination.com
Fri Jan 13 22:26:02 PST 2023

> On 01/13/2023 4:16 PM EST Kristofer Munsterhjelm <km_elmet at t-online.de> wrote:
> ...
> I agree that it could be more clearly stated, though. And as a Condorcet 
> nitpicker, I would probably also say that the paper could mention the 
> theoretical existence of Condorcet cycles in passing, so that the 
> IRVists can't say "hey, the property he desires, that if A beats B 
> pairwise then B can't be elected... it sometimes is impossible to pass! 
> So avert your eyes from this propaganda and support IRV instead!".

I agree that the discussion will inevitably get to superficially citing Arrow or Gibbard-Satterthwaite.  When IRV apologists do that, I want to engage the topic and will use the Minneapolis Ward 2 2021 election as a very nice illustration of when transitivity fails.  I'll explain this will happen less often (0.2%) than the cases when we *know* who the majority candidate is and a spoiled election can be averted but IRV fails to avert it (0.4%).  But with Rock-Paper-Scissors, if you elect Rock, then we know that Scissors is the spoiler.  No matter who you elect, you cannot avoid a spoiled election.  I will be up front with that.

And then I ask how Hare solves it?  It doesn't.  But a Condorcet RCV solves this spoiler problem for the 0.4% of the time Hare fails to.  And will be Precinct Summable to boot.  If they say that I'm worrying too much about this 0.4%, I bring up a comparison to real and rare events when a flaw in a procedure resulted in complete failure to accomplish what is meant to be accomplished.  A good example is of the rare and unfortunate times that the wrong limb was marked and amputated, which has happened occasionally.  When that happens, do we hear the hospital defending themselves saying "This happens so rarely that we believe our procedures that we have used for decades without trouble need not be reviewed."?

So when they bleat "Arrow", I respond that a cycle is an unavoidable failure, so let's do the best we can with it.  Let's elect the plurality winner in that case.  Or elect the IRV winner, or the runoff winner of the top-two.  Or if BTR is used, we accept the BTR winner as just as good as the plurality winner when there is no Consistent Majority Candidate (which is my neologism for the CW).

I'm gonna be quiet now and listen to you guys.  As an activist/schlub, I feel quite privileged to get critique from Markus and Kristofer.


r b-j . _ . _ . _ . _ rbj at audioimagination.com

"Imagination is more important than knowledge."


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