RCV in SF Mayoral election
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@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.txt
curl -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.nameq
java -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@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@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@audioimagination.com mailto:rbj@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@audioimagination.com mailto:rbj@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.
- 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.
- 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?
- 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?
list info
list info
--
r b-j rbj@audioimagination.com
<mailto:rbj@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@voterchoicema.org <mailto:
greg.dennis@voterchoicema.org>
p :: 617.863.0746 tel:617.863.0746
w :: voterchoicema.org http://voterchoicema.org/
:: Follow us on Facebook
https://www.facebook.com/voterchoicema and Twitter
https://twitter.com/voterchoicema ::
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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@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@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.txt
curl -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.nameq
java -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@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@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@audioimagination.com mailto:rbj@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@audioimagination.com mailto:rbj@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.
- 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.
- 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?
- 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?
for
list info
list info
--
r b-j rbj@audioimagination.com
<mailto:rbj@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@voterchoicema.org <mailto:greg.dennis@
voterchoicema.org>
p :: 617.863.0746 tel:617.863.0746
w :: voterchoicema.org http://voterchoicema.org/
:: Follow us on Facebook
https://www.facebook.com/voterchoicema and Twitter
https://twitter.com/voterchoicema ::
Election-Methods mailing list - see http://electorama.com/em for list
info
Election-Methods mailing list - see http://electorama.com/em for list
info
Election-Methods mailing list - see http://electorama.com/em for list
info
Election-Methods mailing list - see http://electorama.com/em for list
info