[EM] Scatter plot of clone independence versus IIA

robert bristow-johnson rbj at audioimagination.com
Wed May 26 10:00:27 PDT 2021

> On 05/26/2021 12:17 PM VoteFair <electionmethods at votefair.org> wrote:
> I'm getting very interesting results from creating a scatter plot that 
> shows success rates for Clone Independence (CI) versus Independence of 
> Irrelevant Alternatives (IIA).  Of course these success-rate percentages 
> convert into failure rates simply by subtracting them from 100.
> Specifically the following chart shows the success-rate percentages for 
> different vote-counting methods using different numbers of candidates.
> https://www.rankedchoiceoregon.org/img/clone_iia_success_rates.jpg


> * IRV-BTR -- Instant-runoff voting with bottom-two runoff -- yields 
> about the same results as IRV.  I included this method in hopes that the 
> results would help Robert in his reform efforts in Burlington.  Alas, 
> unless I've got a bug in the code -- which is very possible -- IRV-BTR 
> isn't looking better than IRV for these two fairness criteria (CI and IIA).

of course the only difference in behavior will be when there is a case like Burlington where a Condorcet winner exists but does not make into the final round with Hare IRV.  i dunno the details of your simulation but i might wonder how many (as a percent) times that happens and how many times a cycle occurred.

my sole selling point (maybe this becomes 4 or 5 selling points as i have enumerated in my paper at https://drive.google.com/file/d/14assN41UL7Mib9PpwsjM63ZT17k9admC/view ) is that plain-language advantages of RCV that are presented to the public are going to be better attained with a Condorcet method.  but most people following RCV don't know what that is.  so i translate "satisfy Condorcet criterion" to "Majority Rule" and i translate "satisfy IIA" to "eliminate the Spoiler Effect" and the only voting tactic i worry about is "compromising" because that is the most common problem and is directly related to the spoiler effect.  and i am also trying to appeal to the Precinct Summability issue because it relates directly to transparency in elections and decentralization of the tallying of ballots.  that speaks to election integrity and puts up another bulwark against hacking and corruption in elections.

in other words, i want to make RCV live up to its promise.

Here is a Vermont update:  Because, because city charter changes require state legislative approval and because of heavy load on the legislature regarding covid and the economic consequences, the Gov Ops committee was too busy to deal with the RCV charter change even though it passed the voters of Burlington with a 64% majority.  Some legislators read my paper and it has influenced them.  It is not dead, but it is in hibernation until 2022.  Then we're gonna have a big fight and, again, I will be asking for help in advocacy.  https://vtdigger.org/2021/05/21/burlington-charter-change-package-stalls-in-committee/ 

BTW, i got involved in a Ranked-Pairs advocacy group centered mostly in Madison Wisconsin, but they got Nicolas Tideman in it.  People here might remember that before I was told about BTR-STV (which is the name I am giving it), that RP with margins was my fav Condorcet method (only because I saw it as simpler than Schulze and easier to sell).  But BTR-STV is even simpler and even easier to sell.  And I can compare it directly to Hare STV.

My hope is that when the "big presentation" happens at the Statehouse in 2022, that I might be able to get *both* Nicolas and Markus and Richard and some others here to testify (via Zoom) before the committee.  I need to fight off the accusation that I am a constituency of 1 and that nobody else cares about this "detail".

Thank you to all for your help and encouragement.  That FairVote train is rolling with a lot of momentum.


r b-j                  rbj at audioimagination.com 

"Imagination is more important than knowledge."

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