[EM] Burlington VT reconsidering IRV 10 years after IRV failed to elect the Condorcet Winner

robert bristow-johnson rbj at audioimagination.com
Wed Dec 4 21:09:04 PST 2019

> On December 4, 2019 11:50 PM VoteFair <electionmethods at votefair.org> wrote:
> In each round, if there is a not-yet-eliminated candidate who is ranked 
> higher on more than half the ballots when that candidate is compared to 
> each and every one of the other not-yet-eliminated candidates on a 
> pairwise (one-on-one) basis, then that pairwise-winning candidate shall 
> be elected.

need to define the "pairwise-winning candidate".

> I'll again repeat my point that the wordings being proposed do not 
> specify what to do with ballots that rank more than one candidate at the 
> same preference level.

Even though for a pure Condorcet, equal ranking is allowed, this does not work for IRV because, when a single candidate is promoted to a voter's effective (contingency) first choice, IRV would not know which of the equally-ranked candidates to promote.  That was clear in previous implementations of IRV.  I am not sure that this languages needs to be on the ballot where voters consider and approve (or reject) IRV.  But it must be on the Instructions to Voters on each ballot.

> If voting will be done electronically then this 
> issue will only affect the few ballots submitted by mail (such as from 
> people overseas in military service), but otherwise this gap will allow 
> many, many ballots to be discarded as "spoiled" even though they are 
> marked in a reasonable way.

I believe our paper-scan IRV software in 2009 was able to handle gaps in the ranking.  You could rank #1, #2, then #5 and if no other ranks are marked, the #5 rank is effectively #3.  All unranked candidates are tied for last place.

> Again, good luck getting at least some improvements.

Thank you.  We shall see.

Just now I sent the working language I had to the city councilors for consideration.  Dunno if they'll listen.


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

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