[EM] VoteFair representation ranking recommended for Czech Green Party

['Richard Fobes']

Markus Schulze wrote:
>
> Richard Fobes wrote (2 May 2010):
> 
>> Once again Markus Schulze is trying to discredit
>> the Condorcet-Kemeny method.
> 
> If I really wanted to discredit this method, then
> I would mention ...

Thank you for giving me the opportunity to put these issues
into perspective.


> ... that this method violates independence of clones.

A violation of the independence-of-clones criteria would
require both of these conditions to occur in the same
election:

* There is circular ambiguity, which means there is no
Condorcet winner.

* Two (or more) of the candidates are recognizable as clones
of one another.

Each of these is uncommon (but not rare), but to have both
in the same election would be rare.

Yes, the Condorcet-Kemeny method fails to meet the
independence-of-clones criteria, whereas the
Condorcet-Schulze method meets this criteria.  This is a
small difference.

For perspective, most of the currently recognized fairness
criteria apply to both the Condorcet-Kemeny and
Condorcet-Schulze methods.  In other words, they meet and
fail most of the same criteria.


> ... that this method has a prohibitive runtime so
> that it is illusory that VoteFair representation
> ranking could ever be used e.g. to fill 7 seats
> out of 30 candidates.

The computer-calculation runtime for getting
Condorcet-Kemeny results is long (factorial according to the
number of candidates) if (!) all the Kemeny scores are
calculated.  However, not all the scores need to be
calculated just to find the sequence with the largest Kemeny
score.

The wording we agreed on in Wikipedia, with the involvement
of a neutral election-method expert, is that calculating the
results for 40 candidates only takes a few seconds if
well-known mathematical techniques are used.  That's not a
prohibitive runtime.

My VoteFair ranking software calculates the results even
faster, using an algorithm that I have not yet revealed.
I'm still looking for a forum in which to share the
algorithm.  (Unlike you, I do not have academic connections
that make it easy to publish papers in academic
publications.)

Yes, it takes the VoteFair ranking software a few seconds
longer to calculate Condorcet-Kemeny results compared to
software that calculates Condorcet-Schulze results.  But
even if the calculation time were a few minutes (for a
particularly convoluted case), such a wait is not a
deterrent for use in real elections.

When the number of candidates reaches 30, the bigger
challenge is for voters to meaningfully rank that many
choices.  That's why I recommend using approval (yes/no)
voting to narrow the candidates to a reasonable number for
ranking.

The Condorcet-Schulze method has this same issue of a ballot
with 30 candidates being difficult to meaningfully rank.


> ... that, although this method has been proposed
> more than 30 years ago, it has never been used by
> a larger organization.

The Condorcet-Kemeny method is impractical to calculate
without a computer, and the Kemeny method was proposed
before computers became widely available, so it's lack of
use prior to a decade ago is not significant.

The Condorcet-Schulze method was the first (of these two
methods) to be implemented in software, and the Condorcet
criteria is so important that it is natural for early
adopters to choose what's available.  But the first
Condorcet method to be adopted in this new digital era is
not necessarily the best.

The benefits of the Kemeny method -- including the fact that
it is a Condorcet method -- are becoming known only slowly.

The popularity of "your" Condorcet-Schulze method reflects
the popularity of Condorcet methods, not necessarily the
popularity of the Schulze-versus-Kemeny choice.  Most of the
people and organizations that use the Condorcet-Schulze
method would not notice any difference in the results if the
Condorcet-Kemeny method were used instead. 

Surely you have noticed that I have not made changes to
"your" "Schulze method" page in Wikipedia, whereas you have
repeatedly attempted to remove every mention of the word
"VoteFair" from the "Kemeny-Young method" page, and to
remove the link that reveals that there is a place where
Condorcet-Kemeny calculations are available (for free).  If
I were more aggressive about promoting the Condorcet-Kemeny
method, or if you were less active about trying to suppress
it, it would be more popular.

It takes time for wise people to make wise decisions.  And
fairness is very important to me.  I'll continue to be
patient as I wait for more people to recognize the
advantages of the Condorcet-Kemeny method (which is a topic
I'll explain in another post, in reply to a fan of "your"
method).

By the way, I don't keep track of all the groups that use
VoteFair ranking.  They find out about it online somewhere,
they use it to elect their organization's officers, and I
never hear about it.  Occasionally I peek at the file
contents to see how my free VoteFair ranking service is
being used, make sure it's not being abused, verify there is
no evidence of bugs, and so on.  That's when I get a glimpse
of where it's used.

When someone wants to use it for more than 6 choices (the
default limit), then I get a call or email and I set up a
special Voting ID number, but otherwise it quietly gets
used, without lots of fanfare.  In the case of the San
Francisco Bay Area Curling club, a member called and asked
for help, including a request to handle extra choices;
otherwise I wouldn't have known about the club using
VoteFair ranking.  When I peek at data, I see that many
organizations do not include their name in the title, and
when their name appears I have to keep it anonymous, unless
they contact me and agree to write a testimonial with their
name.

Everyone who has used VoteFair ranking has liked it, and as
far as I know, no one has stopped using it.  The fact that
it is not yet used in as many organizations as the
Condorcet-Schulze method reflects that it has not been
promoted as heavily.  Only us election-method experts know
about the under-the-hood differences between the
Condorcet-Schulze and Condorcet-Kemeny methods.  To most
people the two most-popular Condorcet methods (C-K and C-S)
would appear to be clones.

In fact, that's one reason I haven't felt a need to promote
the Condorcet-Kemeny over the Condorcet-Schulze method.  But
now the Czech Green party wants a fair proportional method,
and that's where VoteFair representation ranking offers a
dramatic advantage.


> ... that many of the claims in your book are
> ridiculous; for example, your claim that
> this method was strategyproof and satisfied
> independence of irrelevant alternatives.

Your Condorcet-Schulze method also fails the "independence
of irrelevant alternatives," so let's make it clear that
your comment about independence-of-irrelevant-alternatives
criteria is not a criticism of the Condorcet-Kemeny method.
Your criticism is about my book.

Well, my book is about real elections, and this effect for
this method is seldom a significant issue in real elections.
If my book were intended for an academic audience, then of
course it would be appropriate to talk about special edge
cases in which adding a non-winning candidate can cause the
first-most popular candidate to drop down in popularity
ranking.  (For the record, the book does not refer to the
independence of irrelevant alternatives criteria, so where
did you get the idea that it claims to satisfy that
criteria?)

Regarding "strategyproof," the book talks about real
elections, not edge cases where one, or a relatively few,
ballots can cause the results to change.  The portion about
the Condorcet-Kemeny method (called VoteFair popularity
ranking in the book) refers to single-winner elections, not
filling multiple seats.  In single-winner real elections,
the only strategies to which the Condorcet-Kemeny method is
vulnerable involve shifting the results into a case of
circular ambiguity, where there is no Condorcet winner, or
exploiting a naturally occurring circular ambiguity.  In
such a case of circular ambiguity, any strategy that changes
the results would be risky, and could easily backfire.
Also, it would require comprehensive and accurate knowledge
of how other voters will vote, and that knowledge is not
available in real elections.

In real voting situations where VoteFair ranking is used,
the only strategic vulnerability I have observed is burying,
where a large portion (especially when a majority) of the
voters give an insincerely low ranking of an
otherwise-popular competitor.  This causes the contestant to
get a lower-than-expected ranking in the results.  But
that's what any voting method should do.  It reflects what
large numbers of voters, and especially a majority of
voters, express.  But I have not seen burying affect who
"wins" (who is ranked most popular).

If someone makes the mistake of choosing the second-most
popular candidate to fill a second seat, then that would
produce an unfair outcome -- because that would be an
improper use of the method (not because the method is
unfair).  In situations where a second seat is being filled
-- such as the presidential and vice-presidential council
seats in the Czech Green party -- a different method is
needed.  If VoteFair representation ranking is used to fill
the second seat, there is no strategy (that I know of) that
could change who wins either the first or second seat --
without also likely changing (for the worse) who wins the
other seat.

I wrote "Ending The Hidden Unfairness In U.S. Elections" for
a general audience, not for an academic audience.  I figure
that Wikipedia and many other publications already address
academic issues, such as edge cases changing the results.

In my opinion, edge-case issues (and similar academic
arguments) are insignificant compared to the big political
influences such as campaign contributions, advertising and
marketing techniques, election-process unfairnesses (which
are common in certain U.S. states such as Florida,
Louisiana, Texas, New Jersey, and Illinois), and politicians
lying, selling influence, not answering questions, not
taking clear positions, and more.  (The first two chapters
of the book explain lots of political realities that have
nothing to do with vote-counting, but which have far more
influence on election results.)

As an example of the gap between reality and academic
analysis, two politicians who are actually "clones" in terms
of political position would not be recognizable as clones in
a real race because they would claim to be quite different,
which means that an academic analysis to test the results
for "independence of clones" would not be meaningful.

In closing ...

Let's recognize that Peter Zbornik is providing an
opportunity to get fairer voting methods out of the
academic, analysis-paralysis state, and into real elections,
so let's get real:

For the Czech Green party council elections, I have already
recommended VoteFair representation ranking (which uses the
Condorcet-Kemeny method at its core).  I will add that if
the underlying Condorcet-Kemeny method were replaced by the
Condorcet-Schulze method, that would provide nearly the same
results.  More importantly, both of those choices are
significantly better than two-seat STV and approval voting.
And all those methods are better than IRV, three-seat STV,
four-and-more-seat STV, Range voting, and other assorted
methods.

(Yes, I've left out Schulze-STV.  It's a new method and I
don't yet understand it.  (I've tried.)  If I did understand
it, and it looked like it would do what it claims to do,
then I would have indicated where it fits in this list of
methods, which I've prioritized by fairness.)

(To Range-voting fans: Decades from now voters may use range
ballots to provide richer preference information, but we
don't yet have counting methods that handle those ballots in
ways that resist approval-like strategic voting.)

The main point I'm trying to make is that the
Condorcet-Kemeny and Condorcet-Schulze methods are much more
similar than different.

Richard Fobes