[EM] RCV in SF Mayoral election
Christopher Colosi
colosi at gmail.com
Mon Jun 11 18:47:04 PDT 2018
Awesome, I’ll take a look at those. Thanks.
On Mon, Jun 11, 2018 at 10:21 AM Greg Dennis <greg.dennis at voterchoicema.org>
wrote:
> This document describes the layout:
> http://www.acgov.org/rov/rcv/results/226/ballot_image_help.pdf
>
>
> On Mon, Jun 11, 2018 at 11:45 AM, Christopher Colosi <colosi at gmail.com>
> wrote:
>
>> How is the ballot image file laid out? It seems like a horrible choice
>> for formatting. Is there any delimiter between ballots, or is this just
>> one gigantic string of numbers?
>>
>> On Sun, Jun 10, 2018 at 10:42 PM robert bristow-johnson <
>> rbj at audioimagination.com> wrote:
>>
>>>
>>>
>>>
>>>
>>> boy this is embarrassing. i didn't realize they were still counting and
>>> that the lead has changed. looks like London Breed is ahead and will
>>> likely win the STV contest.
>>>
>>> and, from Brian's initial analysis, it doesn't look like the Condorcet
>>> Winner will be different from the STV winner. so no Burlington 2009
>>> situation.
>>>
>>> L8r,
>>>
>>> r b-j
>>>
>>>
>>>
>>> ---------------------------- Original Message
>>> ----------------------------
>>> Subject: Re: [EM] RCV in SF Mayoral election
>>>
>>> From: "robert bristow-johnson" <rbj at audioimagination.com>
>>> Date: Sun, June 10, 2018 10:23 pm
>>> To: "EM" <election-methods at lists.electorama.com>
>>> Cc: "Brian Olson" <bql at bolson.org>
>>>
>>> --------------------------------------------------------------------------
>>>
>>>
>>>
>>> >
>>> >
>>> >
>>> > Thank you Brian for doing this. Looks like Leno is the legit winner
>>> and STV and Condorcet agree.
>>> > However, the Leno-Breed pair wise tally in the defeat matrix should be
>>> exactly the same as the STV final round result. So something is wrong
>>> somewhere.
>>> > But thanks for doing this. I was about to code up a MATLAB program to
>>> parse and count this thing.
>>> >
>>>
>>> > --r b-j rbj at audioimagination.com
>>>
>>>
>>> > "Imagination is more important than knowledge."
>>> >
>>> >
>>> >
>>> >
>>> > -------- Original message --------
>>> >
>>> From: Brian Olson <bql at bolson.org>
>>> > Date: 6/10/2018 7:46 AM (GMT-08:00)
>>> > To: EM <election-methods at lists.electorama.com>
>>> > Subject: Re: [EM] RCV in SF Mayoral election
>>> >
>>> > Ok, a few lines of Python poking the raw data shows I must have some
>>> bug in my Condorcet implementation. Digging into that...
>>> > On Sun, Jun 10, 2018 at 10:08 AM, Greg Dennis <
>>> greg.dennis at voterchoicema.org> wrote:
>>> > Brian, how is it possible that those differ? Since all the other
>>> candidates are eliminated in the final round, shouldn't that necessarily be
>>> the same as the pairwise contest between those two?
>>> >
>>> > On Sun, Jun 10, 2018, 9:46 AM Brian Olson <bql at bolson.org> wrote:
>>> > I processed the latest data (2018-06-09) and posted the results of the
>>> SF Mayor election using a few algorithms:
>>> https://bolson.org/~bolson/2018/SF_Mayor_20180605.html
>>> >
>>>
>>> > The Condorcet win is now 97436 to 91740 for Leno over Breed.The IRV
>>> final round is still just 94783 to 94393.
>>>
>>>
>>> >
>>> > I'm using my software posted at https://github.com/brianolson/voteutil
>>> > commands (needs maven installed for compiling Java, and needs Python3):
>>>
>>> > curl -O
>>> http://www.sfelections.org/results/20180605/data/20180609/20180609_ballotimage.txtcurl
>>> -O
>>> http://www.sfelections.org/results/20180605/data/20180609/20180609_masterlookup.txt
>>> > (mkdir -p ~/psrc && cd ~/psrc && git clone
>>> https://github.com/brianolson/voteutil.git && cd ~/psrc/voteutil/java
>>> && mvn package)python3 ~/psrc/voteutil/python/rcvToNameEq.py -m
>>> 20180609_masterlookup.txt -b 20180609_ballotimage.txt -o
>>> 20180609_%s.nameqjava -jar ~/psrc/voteutil/java/target/voteutil-1.0.0.jar
>>> --rankings --full-html --explain -i 20180609_Mayor.nameq >/tmp/a.html
>>>
>>>
>>> >
>>> > On Sat, Jun 9, 2018 at 9:33 PM, Greg Dennis <
>>> greg.dennis at voterchoicema.org> wrote:
>>> > I quickly looked at the vote data and saw that lots of ballots are
>>> categorized as "Exhausted by Over Votes" and "Under Votes," but there is no
>>> data indicating exactly how those ballots were marked, so we lack enough
>>> information to be sure of final results.
>>> > Actually, all the data you need is available from that page. The
>>> "Ballot Image" file will give you the full cast vote record of every
>>> individual ballot, and the "Master Lookup" is the legend that tells you
>>> what each number means. If you have trouble interpreting the numbers, just
>>> ping me!
>>> >
>>> > On Sat, Jun 9, 2018 at 4:36 PM, VoteFair <electionmethods at votefair.org>
>>> wrote:
>>> > On 6/9/2018 6:25 AM, Greg Dennis wrote:
>>> >
>>> >> San Francisco always make the cast vote record public:
>>> >
>>> >>
>>> https://sfelections.sfgov.org/june-5-2018-election-results-detailed-reports
>>> >
>>> >
>>> >
>>> > I quickly looked at the vote data and saw that lots of ballots are
>>> categorized as "Exhausted by Over Votes" and "Under Votes," but there is no
>>> data indicating exactly how those ballots were marked, so we lack enough
>>> information to be sure of final results.
>>> >
>>> >
>>> >
>>> > Converting instant-runoff counts into pairwise counts might be
>>> (probably is?) possible, but I don't have time to do that analysis.
>>> >
>>> >
>>> >
>>> >> The probability of IRV not elected the Condorcet winner appears to be
>>> >
>>> >> exceedingly low in practice. We're up to about ~200 IRV elections
>>> >
>>> >> conducted nationwide since 2004 and Burlington 2009 is the only
>>> >
>>> >> case so far.
>>> >
>>> >
>>> >
>>> > Yes, circular ambiguity -- in which there is no Condorcet winner -- is
>>> rare when the number of ballots exceeds a few hundred.
>>> >
>>> >
>>> >
>>> >> On Sat, Jun 9, 2018 at 2:07 AM, robert bristow-johnson
>>> >
>>> >> <rbj at audioimagination.com <mailto:rbj at audioimagination.com>> wrote:
>>> >
>>> >> the limitation to only three levels of ranking is a problem. if
>>> >
>>> >> someone ranked all three levels and none of the candidates ranked
>>> >
>>> >> were either London Breed nor Mark Leno, that voter was effectively
>>> >
>>> >> "disenfranchised" by being unable to weigh in on the final choice
>>> of
>>> >
>>> >> choosing the mayor.
>>> >
>>> >
>>> >
>>> > Based on a very quick guesstimate it looks like about 30 or so ballots
>>> had this issue. Right?
>>> >
>>> >
>>> >
>>> > That's not a big number, but a fair counting method -- such as
>>> pairwise counting -- would not have to discard any ballots.
>>> >
>>> >
>>> >
>>> > The bigger number is "under votes" and admittedly pairwise counting
>>> cannot compensate for a voter saying "here is the only acceptable choice"
>>> (or two choices in this case).
>>> >
>>> >
>>> >
>>> > It's great that these results are getting analyzed by people who do
>>> not drink the FairVote kool-aid.
>>> >
>>> >
>>> >
>>> > In haste,
>>> >
>>> > Richard Fobes
>>> >
>>> > "The VoteFair guy"
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > On 6/9/2018 6:25 AM, Greg Dennis wrote:
>>> >
>>> >
>>> > San Francisco always make the cast vote record public:
>>> >
>>> >
>>> https://sfelections.sfgov.org/june-5-2018-election-results-detailed-reports
>>> >
>>> >
>>> >
>>> > Based on the most recent analysis of these numbers that I saw, Leno was
>>> >
>>> > indeed the Condorcet winner, and if Breed were to beat Leno in the
>>> final
>>> >
>>> > round, she would then necessarily be the Condorcet winner. The
>>> >
>>> > probability of IRV not elected the Condorcet winner appears to be
>>> >
>>> > exceedingly low in practice. We're up to about ~200 IRV elections
>>> >
>>> > conducted nationwide since 2004 and Burlington 2009 is the only case
>>> so far.
>>> >
>>> >
>>> >
>>> > On Sat, Jun 9, 2018 at 2:07 AM, robert bristow-johnson
>>> >
>>> > <rbj at audioimagination.com <mailto:rbj at audioimagination.com>> wrote:
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > Richard, a few points:
>>> >
>>> >
>>> >
>>> > the limitation to only three levels of ranking is a problem. if
>>> >
>>> > someone ranked all three levels and none of the candidates ranked
>>> >
>>> > were either London Breed nor Mark Leno, that voter was effectively
>>> >
>>> > "disenfranchised" by being unable to weigh in on the final choice
>>> of
>>> >
>>> > choosing the mayor. however, i think the news media made it clear
>>> >
>>> > that the race was really gonna be between Leno, Breed, and Kim, so
>>> >
>>> > these fringe voters might have a chance to insincerely mark either
>>> >
>>> > Leno or Breed as their 3rd choice and betray their *true* third
>>> >
>>> > choice and, in doing so, have an effect in the final round.
>>> >
>>> >
>>> >
>>> > ignoring the problem of only 3 ranking levels, it is not possible
>>> >
>>> > that London Breed is the Condorcet Winner (a.k.a. "pairwise
>>> >
>>> > champion"). it might be the case that Mark Leno or Jane Kim is the
>>> >
>>> > Condorcet Winner and if the latter is the case, this is another
>>> real
>>> >
>>> > indictment against STV or IRV as a method of tallying RCV. and
>>> your
>>> >
>>> > reverse namesake, FairVote, is partially (or mostly) to blame.
>>> >
>>> >
>>> >
>>> > i wonder if the City of SF has a file of all of the cast and
>>> scanned
>>> >
>>> > ballots and the full ranking for each. if so, and if they release
>>> >
>>> > it to the public, we can investigate if there is a Condorcet Winner
>>> >
>>> > and if that CW is or is not Mark Leno. this would be interesting.
>>> >
>>> >
>>> >
>>> > L8r,
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > r b-j
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > > On 6/8/2018 6:24 PM, Christopher Colosi wrote:
>>> >
>>> > > > ... She stated “This is the system we are working with. That’s
>>> >
>>> > > > a discussion we can have at a later time. For now, we’re stuck
>>> >
>>> > with it.”
>>> >
>>> > > > - insinuating it is not fair. I was quite bothered to have a
>>> Dem
>>> >
>>> > in a
>>> >
>>> > > > progressive city insinuate that first past the post is more
>>> >
>>> > fair. ...
>>> >
>>> > >
>>> >
>>> > > This remark does not imply support for first past the post (FPTP,
>>> >
>>> > a.k.a
>>> >
>>> > > plurality counting).
>>> >
>>> > >
>>> >
>>> > > There are other ways to count the preference marks on
>>> "ranked-choice"
>>> >
>>> > > ballots. In particular, pairwise counting could be used instead
>>> of
>>> >
>>> > > instant-runoff counting, and that is fairer than FPTP.
>>> >
>>> > >
>>> >
>>> > > > 1. May not elect majority candidate
>>> >
>>> > > > ...
>>> >
>>> > > > Is this common? This is
>>> >
>>> > > > probably an abnormally close race. Thoughts?
>>> >
>>> > >
>>> >
>>> > > I doubt the voters would regard this as a close race if they had
>>> been
>>> >
>>> > > able to fully rank all the choices. The 3-choice limitation is
>>> >
>>> > > simplistic, and complicates the counting.
>>> >
>>> > >
>>> >
>>> > > Pairwise counting does not result in any exhausted ballots.
>>> Unmarked
>>> >
>>> > > choices are an indication that the choices are equally disliked.
>>> And
>>> >
>>> > > multiple candidates being marked at the same preference level is
>>> >
>>> > also no
>>> >
>>> > > problem.
>>> >
>>> > >
>>> >
>>> > > In other words, the ballots contain enough information that they
>>> >
>>> > can be
>>> >
>>> > > counted in other ways, besides instant-runoff counting. Those
>>> >
>>> > alternate
>>> >
>>> > > counting methods could reveal a clearer outcome.
>>> >
>>> > >
>>> >
>>> > > In haste,
>>> >
>>> > > Richard Fobes
>>> >
>>> > >
>>> >
>>> > >
>>> >
>>> > > On 6/8/2018 6:24 PM, Christopher Colosi wrote:
>>> >
>>> > >> Curious to hear people’s thoughts on some issues.
>>> >
>>> > >>
>>> >
>>> > >> 1. May not elect majority candidate
>>> >
>>> > >> In SF, we restrict to 3 choices to simplify the process. As the
>>> vote
>>> >
>>> > >> currently stands, 144 votes separate the top two candidates
>>> >
>>> > (<0.1%) and
>>> >
>>> > >> over 16,000 ballots have been exhausted (all 3 choices
>>> eliminated).
>>> >
>>> > >> About 9% of voters have been removed from the pool. It is very
>>> >
>>> > possible
>>> >
>>> > >> that the result would have shifted if they had the opportunity
>>> to
>>> >
>>> > rank a
>>> >
>>> > >> 4th candidate, and therefore, it is possible that we won’t
>>> elect the
>>> >
>>> > >> person who truly represents the majority. Is this common? This
>>> is
>>> >
>>> > >> probably an abnormally close race. Thoughts?
>>> >
>>> > >>
>>> >
>>> > >> 2. What are your thoughts on London Breed’s response to being
>>> >
>>> > asked if
>>> >
>>> > >> RCV is fair? She stated “This is the system we are working with.
>>> >
>>> > That’s
>>> >
>>> > >> a discussion we can have at a later time. For now, we’re stuck
>>> >
>>> > with it.”
>>> >
>>> > >> - insinuating it is not fair. I was quite bothered to have a
>>> Dem in a
>>> >
>>> > >> progressive city insinuate that first past the post is more
>>> fair. It
>>> >
>>> > >> also felt divisive. If Leno wins, will her supporters feel that
>>> >
>>> > >> democracy prevailed, or that the election was stolen? She also
>>> >
>>> > presents
>>> >
>>> > >> herself as a minority candidate and it is my understanding that
>>> RCV
>>> >
>>> > >> gives minority candidates better chances and causes all
>>> >
>>> > candidates to be
>>> >
>>> > >> more likely to campaign to minority communities. Am I mistaken?
>>> Are
>>> >
>>> > >> there any legitimate arguments that FPTP can be more fair?
>>> Thoughts?
>>> >
>>> > >>
>>> >
>>> > >> Regards,
>>> >
>>> > >> —Chris
>>> >
>>> > >>
>>> >
>>> > >>
>>> >
>>> > >>
>>> >
>>> > >> ----
>>> >
>>> > >> Election-Methods mailing list - see http://electorama.com/em
>>> for
>>> >
>>> > list info
>>> >
>>> > >>
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>>> >
>>> > > Election-Methods mailing list - see http://electorama.com/em for
>>> >
>>> > list info
>>> >
>>> > >
>>> >
>>> >
>>> >
>>> > --
>>> >
>>> >
>>> >
>>> > r b-j rbj at audioimagination.com
>>> >
>>> > <mailto:rbj at audioimagination.com>
>>> >
>>> >
>>> >
>>> > "Imagination is more important than knowledge."
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > ----
>>> >
>>> > Election-Methods mailing list - see http://electorama.com/em for
>>> >
>>> > list info
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > --
>>> >
>>> > *Greg Dennis, Ph.D. :: Policy Director*
>>> >
>>> > Voter Choice Massachusetts
>>> >
>>> >
>>> >
>>> > e :: greg.dennis at voterchoicema.org <mailto:
>>> greg.dennis at voterchoicema.org>
>>> >
>>> > p :: 617.863.0746 <tel:617.863.0746>
>>> >
>>> > w :: voterchoicema.org <http://voterchoicema.org/>
>>> >
>>> >
>>> >
>>> > :: Follow us on Facebook
>>> >
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>>> >
>>> > <https://twitter.com/voterchoicema> ::
>>> >
>>> >
>>> >
>>> >
>>> >
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>>> >
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>>>
>>> --
>>>
>>> r b-j rbj at audioimagination.com
>>>
>>> "Imagination is more important than knowledge."
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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