[EM] i also liked what FairVote says about IRV and monotonicity.

[robert bristow-johnson]

"Instant Runoff (IRV): monotonicity criterion - Both two-election runoffs and IRV can fail the monotonicity criterion because voters who shift to this otherwise winning candidate may shift their votes away from the candidate who would otherwise be in the runoff, resulting in a different, and stronger opponent in the final runoff, who may defeat the otherwise winner. Many election experts dismiss this criterion as having no real world impact (for more details see www.fairvote.org/monotonicity, and Austen-Smith and Banks [1998])."

i don't know how you can definitively cite an example of failure, since we would have to turn back the clock, rerun the election and show that somehow, the legitimate winner would have won with fewer votes for him/her.  what we *can* show (and this was exactly the case for Burlington 2009) is that if some voters had, on their way to the polls, changed their mind and changed their first-choice vote from someone who had lost, to the candidate who had actually won, that this previously winning candidate will lose (not to the previous first choice who lost, but to the Condorcet winner who did not make it to the final IRV round).  this is clearly the case in the Burlington 2009 election as Warren Smith had pointed out in http://rangevoting.org/Burlington.html .  how can FairVote deny non-monotonicity in IRV?




also i found a place where Clay Shentrup (or "CS") also tells us that Range and Approval do better than Condorcet in electing the Condorcet winner.  more "up is down" and "black is white" logic.



--

r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."

-----Original Message-----
From: "robert bristow-johnson" [rbj at audioimagination.com]
Date: 10/10/2011 22:57
To: election-methods at lists.electorama.com
Subject: Re: [EM] Critique of FairVote's "approval voting" report


dunno if i can do much critiquing of that particular doc.  what i like is in FairVote's page:

  http://www.fairvote.org/single-winner-voting-method-comparison-chart 

where they claim that IRV will do a better job getting the Condorcet winner than does Condorcet (sometimes the Condorcet method will *fail* to elect the Condorcet winner for those who didn't know that):

"IRV will generally elect a Condorcet winner, ... IRV may actually do a better job of electing Condorcet winners that nominal Condorcet voting methods, because of the incentives for strategic voting under Condorcet rules that are absent under IRV.
...
Condorcet voting is designed specifically to find and elect a Condorcet winner whenever such a candidate exists. Ironically, due to incentives for strategic voting inherent in Condorcet methods, they may in fact fail to elect the Condorcet winner, even when one exists."

i know, so up is down, black is white, etc.


--

r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."

-----Original Message-----
From: "Jameson Quinn" [jameson.quinn at gmail.com]
Date: 10/10/2011 18:26
To: "electionsciencefoundation" <electionscience at googlegroups.com>, "EM" <election-methods at lists.electorama.com>
Subject: [EM] Critique of FairVote's "approval voting" report

I would like to make a detailed critique of the FairVote report theyve put up at approvalvoting.blogspot.com and rangevoting.com. I believe that every single one of the conclusions of that report is dangerously wrong. Ive created a google doc to help make this critique collaboratively. Please add comments to the doc to help critique.

Thanks,
Jameson