[EM] Best IRV Tweak

[robert bristow-johnson]

> On 07/06/2021 3:17 PM Susan Simmons <suzerainsimmons at outlook.com> wrote:
> 
> 
> -------- Original message --------
> From: Susan Simmons <suzerainsimmons at outlook.com>
> Date: 7/6/21 12:14 PM (GMT-08:00)
> To: Susan Simmons <suzerainsimmons at outlook.com>
> Subject: Re: Best IRV Tweak (correction)
> 
> 
> Pairwise support matrix (not pairwise win matrix)
> 
> 
> To be definite, the jth entry in the ith row is the number of ballots on which candidate i is ranked ahead of candidate j.
> 
> 
> 
> -------- Original message --------
> From: Susan Simmons <suzerainsimmons at outlook.com>
> Date: 7/6/21 11:59 AM (GMT-08:00)
> To: election-methods at lists.electorama.com
> Subject: Best IRV Tweak
> 
> 
> 
> 
> While there remains more than one uneliminated candidate eliminate the remaining one that is weakest relative to the other remaining candidates.
> 
> 
> If "weakest" means least top support (relative to the other remaining candidates) then we have IRV.
> 
> 
> But if we interpret "weakest" to mean the candidate with the fewest votes in any head-to-head contest (among the remaining candidates) then we have a Condorcet Compliant method.
> 
> 
> In fact, the weakest candidate in this sense is a pairwise loser to its opponent in its worst head-to-head contest ... which could not happen to a Condorcet Candidate.
>

Susan, as best as i can tell, this is exactly BTR-STV, which is what i am now trying to persuade the legislature of Vermont to adopt instead of Hare STV (which is the label i am using for what we often call "IRV").  See page 7 in this: https://drive.google.com/file/d/1hh0kWBn7LzxkHkJ_r6FsDyBNmnjC7x4o/view

so i agree that this is the best IRV tweek.  it has a better chance of becoming law in my lifetime than either Schulze or Ranked-Pairs, which i think are superior RCV tabulation methods.  but since they are all Condorcet compliant, the only way they can be practically better than BTR-STV is 1) any STV method can't have equal ranking on the ballot unless we put in fractional votes, and 2) Schulze and RP may deal with a cycle (which has never been known to happen in a government election) better than BTR.

so, for me, getting **any** Condorcet compliant method is better than holding out for the best Condorcet method.

 
> 
> Operationally, this method is much simpler than IRV:
> 

only because of precinct summability.  otherwise, it's more work than Hare STV.


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

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