IRV failure modes, vote splitting
[I'm not subscribed, so please CC me on responses]
After looking at Burlington, VT 2009, I've started to ask some questions
about IRV. I strongly prefer Tideman's Alternative Smith.
IRV eventually reduces to a three-way race, and I see some interesting
things occur there.
In Plurality, you can add a candidate on the same ideological end as your
opponent—if your opponent is more-liberal than you, then add another
more-liberal opponent—and you split the vote. This lets you win a close
race when you can't get majority.
In IRV, you also need to add a candidate, and the same rules kind of work.
By adding a conservative to a two-liberal race, you siphon votes from your
moderate (winning) opponent.
That happened in 2009: Bob Kiss loses; add Kurt Wright and Kurt Wright
wins plurality, Montroll has the fewest votes and is eliminated, Kiss beats
Wright and wins.
Interesting thoughts.
In the three-way race, it looks like Plurality without Majority elects the
Condorcet loser. Kurt Wright lost to both Kiss and Montroll, and didn't
have a majority. Lacking a majority, pulling the center candidate would
tend to favor your opponent. This is because Conservatives will roughly
split between two Conservatives; Liberals will roughly split between two
Liberals; and so the three-way race necessarily has an imbalance whereby
there are more Conservatives or more Liberals, and so a split vote
resulting in no majority winner implies that there are more of the group
splitting the vote. The plurality winner is smaller than this group, and
so is the Condorcet loser.
That's a logical outcome, not a mathematical one. We can construct
situations where the liberals abandon the more-liberal candidate for the
conservative; that's not likely in practice.
As per vote splitting, above, this three-way situation would tend to take
votes from the more-center candidate. The more-center candidate would be a
second choice for both ends, and so typically has overwhelming support
against each candidate WHEN THERE IS NO MAJORITY WINNER.
That suggests IRV provides no real advantage in the three-way race:
-
If Plurality isn't a Majority, IRV falls to vote-splitting and never
elects the Condorcet candidate, but avoids the Condorcet loser. -
If Plurality IS a Majority, IRV elects THE SAME CANDIDATE as Plurality,
providing no advantage over Plurality in a three-way race. That candidate
is the Condorcet candidate. -
When encountering a three-way Smith Set, Tideman's Alternative Smith is
identical to IRV after eliminating all non-Smith candidates.
These are, again, practical outcomes, not mathematical ones.
IRV's single advantage over Plurality appears to be that it mathematically
avoids the Condorcet loser, although when doing so it practically
eliminates the Condorcet winner.
---------------------------- Original Message ----------------------------
Subject: [EM] IRV failure modes, vote splitting
From: "John" john.r.moser@gmail.com
Date: Wed, December 19, 2018 10:34 pm
To: election-methods@electorama.com
[I'm not subscribed, so please CC me on responses]
After looking at Burlington, VT 2009, I've started to ask some questions
about IRV.
what were you looking at?� this, from Warren Smith?:
� �https://rangevoting.org/Burlington.html
It's a good analysis.� don't let this excellent analysis of the Burlington 2009 get conflated with all of Warren's claims about Score Voting or Approval Voting.
also
(other people on this list know this), i am a Burlington resident (i happen to live in Bernie's ward), politically active, and was there in 2009.� at the time Andy Montroll was a friend of mine.
I strongly prefer Tideman's Alternative Smith.
personally, i think that Tideman Ranked Pairs (using margins) is just better.� and it's simpler.
IRV eventually reduces to a three-way race, and I see some interesting
things occur there.
In Plurality, you can add a candidate on the same ideological end as your
opponent—if your opponent is more-liberal than you, then add another
more-liberal opponent—and you split the vote. This lets you win a close
race when you can't get majority.
In IRV, you also need to add a candidate, and the same rules kind of work.
By adding a conservative to a two-liberal race, you siphon votes from your
moderate (winning) opponent.
well, yes, but most of the moderate liberal voters had marked the more liberal as their second choice and also the reciprocal.
That happened in 2009: Bob Kiss loses; add Kurt Wright and Kurt Wright
wins plurality, Montroll has the fewest votes and is eliminated, Kiss beats
Wright and wins.
Andy had the fewest 1st-choice votes of the three, but he was the 2nd-choice of most of Kurt's voters and nearly all of Bob's voters.
Interesting thoughts.
In the three-way race, it looks like Plurality without Majority elects the
Condorcet loser. Kurt Wright lost to both Kiss and Montroll,
in a pair-wise comparison, yes.� loses to Andy by 929 votes and lost to Bob by 252 votes (out of nearly 9000).
and didn't
have a majority. Lacking a majority, pulling the center candidate would
tend to favor your opponent. This is because Conservatives will roughly
split between two Conservatives; Liberals will roughly split between two
Liberals; and so the three-way race necessarily has an imbalance whereby
there are more Conservatives or more Liberals, and so a split vote
resulting in no majority winner implies that there are more of the group
splitting the vote.
i would put it more simply:� if there is a single-dimensional political spectrum from left to right, the center candidate is far more likely to be preferred as a 2nd-choice to the voters on the extremes than the candidate at the opposite extreme.� both GOP
voters and Prog voters selected the Dem candidate as their second choice.�
The plurality winner is smaller than this group, and
so is the Condorcet loser.
That's a logical outcome, not a mathematical one. We can construct
situations where the liberals abandon the more-liberal candidate for the
conservative; that's not likely in practice.
As per vote splitting, above, this three-way situation would tend to take
votes from the more-center candidate. The more-center candidate would be a
second choice for both ends, and so typically has overwhelming support
against each candidate WHEN THERE IS NO MAJORITY WINNER.
well, we need to define exactly what we mean by a "majority winner".� if there are three or more candidates it's possible no single candidate gets majority support.� but between any pair of candidates, there is a
majority winner unless they tie.
that's all Condocet does.� just pairs the candidates with all possible pair combinations and says consistently, "If more voters mark their ballots preferring Candidate A to Candidate B than voters marking the contrary, then Candidate B is not
elected."� that simple rule pretty much defines Condorcet.� and the problem in Burlington 2009 was 587 more voters marked their ballots that they preferred Andy over Bob than the number of voters preferring Bob over Andy, yet Bob was elected.
That suggests IRV provides no real advantage in the three-way race:
�
IRV doesn't do too bad in a 3-way race if one of those three has far less support than the other two.� but in Burlington 2009, all three had approximately equal support.� the Prog was the IRV winner, the GOP was the FPTP winner, and the centrist Democrat was the Condorcet
winner.� any of those three were a plausible winner.
i don't know of another governmental race using Ranked-Choice Voting (what they now call it) where the method failed to elect the Condorcet winner.� but i think it will happen again.
When the spoiler has virtually no chance
in winning (but a good chance of spoiling), IRV will choose the same as the Condorcet.� it's only when there are 3 or more plausible contenders that this hiccup happens.
�
- If Plurality isn't a Majority, IRV falls to vote-splitting and never
elects the Condorcet candidate, but avoids the Condorcet loser.
- If Plurality IS a Majority, IRV elects THE SAME CANDIDATE as Plurality,
providing no advantage over Plurality in a three-way race. That candidate
is the Condorcet candidate.
- When encountering a three-way Smith Set, Tideman's Alternative Smith is
identical to IRV after eliminating all non-Smith candidates.
These are, again, practical outcomes, not mathematical ones.
IRV's single advantage over Plurality appears to be that it mathematically
avoids the Condorcet loser, although when doing so it practically
eliminates the Condorcet winner.
no it doesn't.� not most of the time.�
again, Burlington 2009 is the only governmental election using RCV i am aware of in which the single-transferable vote method failed to elect the Condorcet winner.� I think all of the other RCV
elections have.
but that's still not a good reason to use IRV over a Condorcet-compliant method.
there are at least 4 solid reasons why IRV failed in Burlington in 2009.� the most important is that it failed to resist a spoiler.� because of that, a promise to the voters that
IRV made: that they would not need to vote tactically, they could serve their political interests well by voting for their favorite first, and marking their second favorite second.� but 1500 Wright voters found out that, simply by marking their favorite as #1, they caused the election of Bob
Kiss, where, if they had been tactical, they could have insincerely bumped Kurt down a notch and let Andy rise to the top and they would have prevented their lowest choice from winning.� it promised this spoiler thing would not happen.
--
r b-j� � � � � � � � � � � � �rbj@audioimagination.com
"Imagination is more important than knowledge."
�
�
�
�
Following is repetitive but not everyone will have heard it. The classic
judgment is by Simon Laplace (backed by JFS Ross), who decided in favor
of Borda method over Condorcet method, because ranks are not of equal
importance. Condorcet has since been weighted (and not arbitrarily like
Borda). But Condorcet appears to be generally a cross-referencing of
some given voting method, for internal consistency, not a method in itself.
IRV/RCV/Alternative Vote suffers from premature exclusion of candidates.
Perhaps because USA is two-party polarised, the Burlington result has
not repeated yet.
An IRV drawback is also potentially true of STV, especially in small
multi-member constituencies. In Ireland in 2016, two brothers got
supporters to allocate extra first preferences to younger brother, to
ensure not excluded on first elimination count. They were elected the
two most popular.
My invention does not eliminate candidates, tho it uses exclusion
counts, as well as election counts: "FAB STV: Four Averages Binomial
Single Transferable Vote" maximises ranked choice information by
counting all ranked choices, thru keep values (weighting) of preference
and unpreference (reverse preference) and, in both cases, abstention
(possibly making a quota for leaving a seat empty).
Official elections are generally "uninomial" (preference-only)
The difference of FAB STV from the voters viewpoint is that they have
Bidirectional preference (two-way choice).
from
Richard Lung.
On 20/12/2018 05:15, robert bristow-johnson wrote:
---------------------------- Original Message ----------------------------
Subject: [EM] IRV failure modes, vote splitting
From: "John" john.r.moser@gmail.com
Date: Wed, December 19, 2018 10:34 pm
To: election-methods@electorama.com
[I'm not subscribed, so please CC me on responses]
After looking at Burlington, VT 2009, I've started to ask some questions
about IRV.
what were you looking at? this, from Warren Smith?:
https://rangevoting.org/Burlington.html
It's a good analysis. don't let this excellent analysis of the
Burlington 2009 get conflated with all of Warren's claims about Score
Voting or Approval Voting.
also (other people on this list know this), i am a Burlington resident
(i happen to live in Bernie's ward), politically active, and was there
in 2009. at the time Andy Montroll was a friend of mine.
I strongly prefer Tideman's Alternative Smith.
personally, i think that Tideman Ranked Pairs (using margins) is just
better. and it's simpler.
IRV eventually reduces to a three-way race, and I see some interesting
things occur there.
In Plurality, you can add a candidate on the same ideological end as
your
opponent—if your opponent is more-liberal than you, then add another
more-liberal opponent—and you split the vote. This lets you win a close
race when you can't get majority.
In IRV, you also need to add a candidate, and the same rules kind of
work.
By adding a conservative to a two-liberal race, you siphon votes
from your
moderate (winning) opponent.
well, yes, but most of the moderate liberal voters had marked the more
liberal as their second choice and also the reciprocal.
That happened in 2009: Bob Kiss loses; add Kurt Wright and Kurt Wright
wins plurality, Montroll has the fewest votes and is eliminated,
Kiss beats
Wright and wins.
Andy had the fewest 1st-choice votes of the three, but he was the
2nd-choice of most of Kurt's voters and nearly all of Bob's voters.
Interesting thoughts.
In the three-way race, it looks like Plurality without Majority
elects the
Condorcet loser. Kurt Wright lost to both Kiss and Montroll,
in a pair-wise comparison, yes. loses to Andy by 929 votes and lost
to Bob by 252 votes (out of nearly 9000).
and didn't
have a majority. Lacking a majority, pulling the center candidate would
tend to favor your opponent. This is because Conservatives will roughly
split between two Conservatives; Liberals will roughly split between two
Liberals; and so the three-way race necessarily has an imbalance whereby
there are more Conservatives or more Liberals, and so a split vote
resulting in no majority winner implies that there are more of the group
splitting the vote.
i would put it more simply: if there is a single-dimensional
political spectrum from left to right, the center candidate is far
more likely to be preferred as a 2nd-choice to the voters on the
extremes than the candidate at the opposite extreme. both GOP voters
and Prog voters selected the Dem candidate as their second choice.
The plurality winner is smaller than this group, and
so is the Condorcet loser.
That's a logical outcome, not a mathematical one. We can construct
situations where the liberals abandon the more-liberal candidate for the
conservative; that's not likely in practice.
As per vote splitting, above, this three-way situation would tend to
take
votes from the more-center candidate. The more-center candidate
would be a
second choice for both ends, and so typically has overwhelming support
against each candidate WHEN THERE IS NO MAJORITY WINNER.
well, we need to define exactly what we mean by a "majority winner".
if there are three or more candidates it's possible no single
candidate gets majority support. but between any pair of candidates,
there is a majority winner unless they tie.
that's all Condocet does. just pairs the candidates with all possible
pair combinations and says consistently, "If more voters mark their
ballots preferring Candidate A to Candidate B than voters marking the
contrary, then Candidate B is not elected." that simple rule pretty
much defines Condorcet. and the problem in Burlington 2009 was 587
more voters marked their ballots that they preferred Andy over Bob
than the number of voters preferring Bob over Andy, yet Bob was elected.
That suggests IRV provides no real advantage in the three-way race:
IRV doesn't do too bad in a 3-way race if one of those three has far
less support than the other two. but in Burlington 2009, all three
had approximately equal support. the Prog was the IRV winner, the GOP
was the FPTP winner, and the centrist Democrat was the Condorcet
winner. any of those three were a plausible winner.
i don't know of another governmental race using Ranked-Choice Voting
(what they now call it) where the method failed to elect the Condorcet
winner. but i think it will happen again.
When the spoiler has virtually no chance in winning (but a good chance
of spoiling), IRV will choose the same as the Condorcet. it's only
when there are 3 or more plausible contenders that this hiccup happens.
-
If Plurality isn't a Majority, IRV falls to vote-splitting and never
elects the Condorcet candidate, but avoids the Condorcet loser. -
If Plurality IS a Majority, IRV elects THE SAME CANDIDATE as
Plurality,
providing no advantage over Plurality in a three-way race. That
candidate
is the Condorcet candidate.
- When encountering a three-way Smith Set, Tideman's Alternative
Smith is
identical to IRV after eliminating all non-Smith candidates.
These are, again, practical outcomes, not mathematical ones.
IRV's single advantage over Plurality appears to be that it
mathematically
avoids the Condorcet loser, although when doing so it practically
eliminates the Condorcet winner.
no it doesn't. not most of the time.
again, Burlington 2009 is the only governmental election using RCV i
am aware of in which the single-transferable vote method failed to
elect the Condorcet winner. I think all of the other RCV elections have.
but that's still not a good reason to use IRV over a
Condorcet-compliant method.
there are at least 4 solid reasons why IRV failed in Burlington in
2009. the most important is that it failed to resist a spoiler.
because of that, a promise to the voters that IRV made: that they
would not need to vote tactically, they could serve their political
interests well by voting for their favorite first, and marking their
second favorite second. but 1500 Wright voters found out that, simply
by marking their favorite as #1, they caused the election of Bob Kiss,
where, if they had been tactical, they could have insincerely bumped
Kurt down a notch and let Andy rise to the top and they would have
prevented their lowest choice from winning. it promised this spoiler
thing would not happen.
--
r b-j rbj@audioimagination.com
"Imagination is more important than knowledge."
Election-Methods mailing list - see http://electorama.com/em for list info
I think we may need a better theory to explain why IRV elects the Condorcet
candidate with near-perfect frequency in practice. We're now somewhere
around 215 IRV elections in the US since San Francisco started in 2004, and
Burlington 2009 is still the only case. That includes many highly
competitive, crowded fields with more than 2 strong candidates, including
the Minneapolis mayoral race last year and the San Francisco Mayoral race
and Maine Democratic gubernatorial primary this year. Probably a decent
research project there for the taking.
On Thu, Dec 20, 2018, 2:33 PM Richard Lung <voting@ukscientists.com wrote:
Following is repetitive but not everyone will have heard it. The classic
judgment is by Simon Laplace (backed by JFS Ross), who decided in favor of
Borda method over Condorcet method, because ranks are not of equal
importance. Condorcet has since been weighted (and not arbitrarily like
Borda). But Condorcet appears to be generally a cross-referencing of some
given voting method, for internal consistency, not a method in itself.
IRV/RCV/Alternative Vote suffers from premature exclusion of candidates.
Perhaps because USA is two-party polarised, the Burlington result has not
repeated yet.
An IRV drawback is also potentially true of STV, especially in small
multi-member constituencies. In Ireland in 2016, two brothers got
supporters to allocate extra first preferences to younger brother, to
ensure not excluded on first elimination count. They were elected the two
most popular.
My invention does not eliminate candidates, tho it uses exclusion counts,
as well as election counts: "FAB STV: Four Averages Binomial Single
Transferable Vote" maximises ranked choice information by counting all
ranked choices, thru keep values (weighting) of preference and unpreference
(reverse preference) and, in both cases, abstention (possibly making a
quota for leaving a seat empty).
Official elections are generally "uninomial" (preference-only)
The difference of FAB STV from the voters viewpoint is that they have
Bidirectional preference (two-way choice).
from
Richard Lung.
On 20/12/2018 05:15, robert bristow-johnson wrote:
---------------------------- Original Message ----------------------------
Subject: [EM] IRV failure modes, vote splitting
From: "John" john.r.moser@gmail.com john.r.moser@gmail.com
Date: Wed, December 19, 2018 10:34 pm
To: election-methods@electorama.com
[I'm not subscribed, so please CC me on responses]
After looking at Burlington, VT 2009, I've started to ask some questions
about IRV.
what were you looking at? this, from Warren Smith?:
https://rangevoting.org/Burlington.html
It's a good analysis. don't let this excellent analysis of the Burlington
2009 get conflated with all of Warren's claims about Score Voting or
Approval Voting.
also (other people on this list know this), i am a Burlington resident (i
happen to live in Bernie's ward), politically active, and was there in
2009. at the time Andy Montroll was a friend of mine.
I strongly prefer Tideman's Alternative Smith.
personally, i think that Tideman Ranked Pairs (using margins) is just
better. and it's simpler.
IRV eventually reduces to a three-way race, and I see some interesting
things occur there.
In Plurality, you can add a candidate on the same ideological end as your
opponent—if your opponent is more-liberal than you, then add another
more-liberal opponent—and you split the vote. This lets you win a close
race when you can't get majority.
In IRV, you also need to add a candidate, and the same rules kind of
work.
By adding a conservative to a two-liberal race, you siphon votes from
your
moderate (winning) opponent.
well, yes, but most of the moderate liberal voters had marked the more
liberal as their second choice and also the reciprocal.
That happened in 2009: Bob Kiss loses; add Kurt Wright and Kurt Wright
wins plurality, Montroll has the fewest votes and is eliminated, Kiss
beats
Wright and wins.
Andy had the fewest 1st-choice votes of the three, but he was the
2nd-choice of most of Kurt's voters and nearly all of Bob's voters.
Interesting thoughts.
In the three-way race, it looks like Plurality without Majority elects
the
Condorcet loser. Kurt Wright lost to both Kiss and Montroll,
in a pair-wise comparison, yes. loses to Andy by 929 votes and lost to
Bob by 252 votes (out of nearly 9000).
and didn't
have a majority. Lacking a majority, pulling the center candidate would
tend to favor your opponent. This is because Conservatives will roughly
split between two Conservatives; Liberals will roughly split between two
Liberals; and so the three-way race necessarily has an imbalance whereby
there are more Conservatives or more Liberals, and so a split vote
resulting in no majority winner implies that there are more of the group
splitting the vote.
i would put it more simply: if there is a single-dimensional political
spectrum from left to right, the center candidate is far more likely to be
preferred as a 2nd-choice to the voters on the extremes than the candidate
at the opposite extreme. both GOP voters and Prog voters selected the Dem
candidate as their second choice.
The plurality winner is smaller than this group, and
so is the Condorcet loser.
That's a logical outcome, not a mathematical one. We can construct
situations where the liberals abandon the more-liberal candidate for the
conservative; that's not likely in practice.
As per vote splitting, above, this three-way situation would tend to take
votes from the more-center candidate. The more-center candidate would be
a
second choice for both ends, and so typically has overwhelming support
against each candidate WHEN THERE IS NO MAJORITY WINNER.
well, we need to define exactly what we mean by a "majority winner". if
there are three or more candidates it's possible no single candidate gets
majority support. but between any pair of candidates, there is a majority
winner unless they tie.
that's all Condocet does. just pairs the candidates with all possible
pair combinations and says consistently, "If more voters mark their ballots
preferring Candidate A to Candidate B than voters marking the contrary,
then Candidate B is not elected." that simple rule pretty much defines
Condorcet. and the problem in Burlington 2009 was 587 more voters marked
their ballots that they preferred Andy over Bob than the number of voters
preferring Bob over Andy, yet Bob was elected.
That suggests IRV provides no real advantage in the three-way race:
IRV doesn't do too bad in a 3-way race if one of those three has far less
support than the other two. but in Burlington 2009, all three had
approximately equal support. the Prog was the IRV winner, the GOP was the
FPTP winner, and the centrist Democrat was the Condorcet winner. any of
those three were a plausible winner.
i don't know of another governmental race using Ranked-Choice Voting (what
they now call it) where the method failed to elect the Condorcet winner.
but i think it will happen again.
When the spoiler has virtually no chance in winning (but a good chance of
spoiling), IRV will choose the same as the Condorcet. it's only when there
are 3 or more plausible contenders that this hiccup happens.
-
If Plurality isn't a Majority, IRV falls to vote-splitting and never
elects the Condorcet candidate, but avoids the Condorcet loser. -
If Plurality IS a Majority, IRV elects THE SAME CANDIDATE as Plurality,
providing no advantage over Plurality in a three-way race. That candidate
is the Condorcet candidate. -
When encountering a three-way Smith Set, Tideman's Alternative Smith is
identical to IRV after eliminating all non-Smith candidates.
These are, again, practical outcomes, not mathematical ones.
IRV's single advantage over Plurality appears to be that it
mathematically
avoids the Condorcet loser, although when doing so it practically
eliminates the Condorcet winner.
no it doesn't. not most of the time.
again, Burlington 2009 is the only governmental election using RCV i am
aware of in which the single-transferable vote method failed to elect the
Condorcet winner. I think all of the other RCV elections have.
but that's still not a good reason to use IRV over a Condorcet-compliant
method.
there are at least 4 solid reasons why IRV failed in Burlington in 2009.
the most important is that it failed to resist a spoiler. because of that,
a promise to the voters that IRV made: that they would not need to vote
tactically, they could serve their political interests well by voting for
their favorite first, and marking their second favorite second. but 1500
Wright voters found out that, simply by marking their favorite as #1, they
caused the election of Bob Kiss, where, if they had been tactical, they
could have insincerely bumped Kurt down a notch and let Andy rise to the
top and they would have prevented their lowest choice from winning. it
promised this spoiler thing would not happen.
--
r b-j rbj@audioimagination.com
"Imagination is more important than knowledge."
Election-Methods mailing list - see http://electorama.com/em for list info
Election-Methods mailing list - see http://electorama.com/em for list info
On Fri, Dec 21, 2018 at 11:33 PM Greg Dennis wrote:
I think we may need a better theory to explain why IRV elects the
Condorcet candidate with near-perfect frequency in practice. We're now
somewhere around 215 IRV elections in the US since San Francisco started in
2004, and Burlington 2009 is still the only case.
How do you know it elected the Condorcet candidate? All of the ballots are
public for all of those elections?
---------------------------- Original Message ----------------------------
Subject: Re: [EM] IRV failure modes, vote splitting
From: fdpk69p6uq@snkmail.com
Date: Fri, December 21, 2018 11:42 pm
To: election-methods@electorama.com
On Fri, Dec 21, 2018 at 11:33 PM Greg Dennis wrote:
I think we may need a better theory to explain why IRV elects the
Condorcet candidate with near-perfect frequency in practice. We're now
somewhere around 215 IRV elections in the US since San Francisco started in
2004, and Burlington 2009 is still the only case.
i'm just saying that i know of no other governmental election using RCV (and all of these RCV elections were using the IRV method of tallying votes) where the IRV winner was not the Condorcet winner.� perhaps there is another
case where the CW loses IRV, but i am not aware of it.
we know that Condorcet winner will likely have some basis of popular support simply in order to become the CW.� we also know that if the CW gets into the IRV final round, the CW wins the IRV election.
now, imagine the race is
boiled down to 3 candidates.� then say that one candidate is a spoiler (i.e. that candidate's presence in the race changes the outcome of the race, but that candidate does not win), another candidate is CW.�
we know that a spoiler who is not a plausible winner, like having
something like 20% first-choice support or less (among the top three candidates), that spoiler will not have enough support to get into the final round, then the CW and the other candidate get into the final round and the CW wins the IRV final round.
How do you know it elected the Condorcet candidate? All of the ballots are
public for all of those elections?
the data of the ballots were public with the Burlington 2009 election.� i still have the files.� and in the last SF mayoral election, i believe there were also files that had the individual ballot data.
then, the bitchy thing is writing a
program in whatever language you like (i did mine in C) to open, read, and parse these files and count the votes under whatever rules.� my program only calculated the pairwise defeat matrix.� Warren Smith's program calculated subtotals for 9 different ballot possibilities once it was
boiled down to 3 candidates.
--
r b-j� � � � � � � � � � � � �rbj@audioimagination.com
"Imagination is more important than knowledge."
�
�
�
�
Public data from virtually all of those elections are here:
https://www.rankedchoicevoting.org/data_clearinghouse
There's a handful not available at that link but nearly all of those
winners had a majority of first choices. Admittedly, I think there's still
a few in the intersection of (no public data) and (no majority of first
choices). The few without public data I think are largely (or all?)
hand-counted. When they're optically-scanned, it's been common practice for
the jurisdiction to post the cast vote records online.
On Fri, Dec 21, 2018 at 11:42 PM fdpk69p6uq@snkmail.com wrote:
On Fri, Dec 21, 2018 at 11:33 PM Greg Dennis wrote:
I think we may need a better theory to explain why IRV elects the
Condorcet candidate with near-perfect frequency in practice. We're now
somewhere around 215 IRV elections in the US since San Francisco started in
2004, and Burlington 2009 is still the only case.
How do you know it elected the Condorcet candidate? All of the ballots
are public for all of those elections?
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
p :: 617.863.0746
w :: voterchoicema.org
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