[EM] my letter to CVD
James Green-Armytage
jarmyta at antioch-college.edu
Sun Apr 4 05:43:02 PDT 2004
Dear Election Methods fans,
Here is a copy of the letter which I wrote to CVD in reply to their IRV
vs. Condorcet draft, minus a few deletions. Comments are more than welcome.
all my best,
James
______________________________________________________
Dear Mr. Richie and Mr. Bouricius,
First of all let me say that I do support IRV. I've been living in
Berkeley since January, and I gave nothing but support to measure I.
However, I still think that Condorcet's method of pairwise comparisons is
the most profound organizing principle for single winner voting, just as
STV is the most profound organizing principle for proportional
representation.
I thank you for taking some time to consider Condorcet's method, and to
draft a statement addressing your concerns with it. I hope that you intend
the statement as part of an ongoing dialogue rather than a final
closing-off of dialogue. Of course I don't ask that you devote all of your
time to such analysis, but just to keep an open mind on it, and to keep
thinking about it when you do have time.
>For example, in some rare cases a voter in an IRV election can hurt a
>candidate by ranking that candidate more highly. Although technically
>true, its importance is negligible because such a rare mathematical
>possibility is almost impossible to anticipate before an election and
>thus of no tactical significance.
I agree that lacking monotonicity isn't a huge problem for IRV. It does
have *some* tactical significance, but it's not fatal. Actually I think
that the problem is theoretically worse in the traditional two round
runoff. For example, a case where a Republican had 45% and two Democrats
were in a near tie around 22% or 23%. Clever Republicans might vote in the
initial election for the Democrat whom they perceive of as being easier
for the Republican to defeat. The problem in IRV is analogous to this, but
less severe because the Republican's vote would have to stick with the
'weak' Democrat until he got eliminated. Successful exploitation of IRV's
lack of monotonicity would indeed be difficult.
>IRV critics who prefer Condorcet also point out that in some scenarios,
>voters in an IRV system could improve the chances of their second
>favorite candidate defeating their least favorite candidate by
>strategically ranking their second choice as number one instead of their
>true favorite candidate (assuring the strongest acceptable candidate
>makes it into the final runoff count, for example, ahead of a candidate
>whom many people like better, but does not have enough centrist appeal to
>win in a runoff). Because of this example they argue incorrectly that
>Condorcet voting is the only system that escapes 100% from insincere
>strategic voting and from the spoiler problem.
I wouldn't argue for a moment that Condorcet (or any other voting method)
is 100% free from strategy. I don't think that any other seasoned
Condorcet supporters would do so either. Condorcet surely does have
strategic vulnerability, and I will get to that in a moment.
However, the problem with IRV that you are pointing out here is indeed a
serious one. This strategy is sometimes known as the "compromising"
strategy. In many cases an IRV result will be improved if people in fact
do use this strategy. However, communication will become distorted, and
the risk of self-fulfilling prophesies appears, such that a voter will
worry that their favorite is non-viable, and compromise in favor of
another candidate, which will in turn assure that their favorite is in
fact non-viable. The fact that voters will be pressured to abandon their
true favorite when their preferred lesser-of-two-evils candidate begins to
run the risk of early elimination means that IRV retains a strong
conservative tendency. That is, it should allow third party candidates to
receive symbolic votes and to gain a bit more legitimacy, but it may not
make it much easier for them to actually win office, since incentives for
the compromise strategy above will kick in precisely at the time when they
are about to become really competitive.
This artificial limiting factor to the number of competitive candidates
is disturbing because it allows corrupt or otherwise undesirable
politicians to stay in place as long as they are preferred over the viable
alternative, which is likely to consist of only a single candidate. For
example, I will note here that in the Australian House of Representatives,
the Labor-versus-Liberal/National establishment has remained immune to
ousters by alternative parties.
Lately I've been trying to look into versions of IRV that allow for equal
ranking. Although it wouldn't get rid of this problem altogether by any
means, I do believe that it would help somewhat, since instead of ranking
their second choice ahead of their first choice, compromising voters could
rank them equal to one another. I think that the two methods of
equal-rankings-allowed IRV (the version using whole votes and the version
using fractional votes) should be looked at carefully.
>In fact Condorcet also creates incentives for insincere voting. All the
>mathematical elegance of Condorcet Voting is irrelevant when it can be so
>obviously gamed through insincere strategic voting. Strategic voting
>occurs when voters have an incentive to rank candidates in an order
>contrary to their true preferences in order to help a preferred candidate
>or block another candidate. Although strategic voting may be possible
>with any voting system, it is in fact a larger problem with Condorcet
>than with IRV.
>Suppose four candidates (A, B, C, and D) are running for an office, where
>candidates A and B are the frontrunners. Consider a voter whose true
>preferences are in order of A, B, C, D. Under Condorcet, by voting
>insincerely this voter can minimize the chances that candidate B will
>defeat his or her preferred candidate A. A voter quickly realizes that
>the best strategy is to punish the strongest competitor to her favorite
>candidate by ranking the candidates insincerely A, C, D, B. Doing so may
>block B - and any candidate -- from becoming the Condorcet winner and
>improve candidate A's chances to win under the fallback rule. Worse yet,
>if both A and B supporters widely engage in such strategic voting, the
>winner could be a candidate most voters actually oppose, but didn't
>realize would benefit from their insincere rankings. With IRV, there
>rarely is an incentive to engage in strategic voting, since later
>rankings do not hurt earlier rankings. In certain unique situations where
>there is widespread availability of detailed polling information, there
>are ways to vote strategically with IRV, but strategic voting is greatly
>limited. There is no rule of general applicability of the value of
>insincere rankings, as there is with Condorcet.
Your criticism here is generally correct and relevant, although it
contains overstatements, such as the sentence: "All the mathematical
elegance of Condorcet Voting is irrelevant when it can be so obviously
gamed through insincere strategic voting." The strategy you are referring
to is sometimes known as the "burying" strategy. I agree that
vulnerability to this strategy is a serious problem for Condorcet (in my
opinion the only serious problem that the better Condorcet methods have),
and it is important to address it just as it is important to address IRV's
problems.
I think that any proposal for the use of Condorcet should keep this
problem in mind and make sure that there are effective safeguards in place
against strategic voting getting out of hand. I myself have been working
on developing such safeguard procedures. A few of the procedures I have
suggested can be found at
http://fc.antioch.edu/~jarmyta@antioch-college.edu/voting_methods/burying_and_remedy.htm
In some cases my proposals involve one or more additional balloting, so
they would admittedly be a difficult sell for public elections in the near
future. However, in a slightly more advanced society I would advocate them
to elect representatives, and in more immediate terms I think that
Condorcet procedures can and should be used for other situations where
multiple ballotings aren't a problem, such as the process of a legislature
deciding between different versions of a bill, or for any voting within a
relatively small group. Also, the strategy would be less of a problem in
any system where the raw votes were used as the basis for further
interpretation rather than producing an instantaneously binding result.
This notion will come into play again later.
>Condorcet has even more important negatives directly related to its
>seemingly sensible goal of selecting the candidate who theoretically
>would beat all others in a one-on-one race. Its biggest flaw is that it
>can elect a candidate who has too little support to be seen as a good
>representative of substantial numbers of voters - a candidate so lacking
>in support to ever be competitive in a traditional plurality or runoff
>election.
In passing, I'll to say that I find it somewhat self-contradictory to
appeal directly to the methods which you are so deeply critical of to
provide a normative argument against Condorcet.
>At an extreme, the Condorcet winner in a four-candidate race might be
>unable to win a single vote in our current election system, but could win
>under Condorcet by avoiding being any voters' last choice. In other
>words, the Condorcet winner's ability to defeat all other candidates in a
>one-on-one race is entirely theoretical because in an election held under
>plurality or runoff rules, their lack of core support would prevent then
>from ever being opposed by just one candidate.
>Here is an election scenario that demonstrates this problematic dynamic
>in Condorcet voting.
>Imagine a polarized election in which:
>Candidate A is favored by 55% of voters who all disapprove of candidate
>B,
>Candidate B is favored by 45% of voters who all disapprove of candidate
>A.
>Now suppose candidate C joins the race and stresses his/her likeability
>and avoids any controversial issues.
>If 15% of the A supporters are drawn to candidate C's friendly image, the
>result would now be:
>Candidate A=40%
>Candidate B=45%
>Candidate C=15%.
>Under plurality rules, Candidate B wins even though 55% of all voters
>consider Candidate B the worst choice
>Both IRV and Condorcet always avoid this fatal flaw. Under IRV rules,
>Candidate C is eliminated in the runoff count and Candidate A again wins
>with 55%.
>Under Condorcet rules, however, if Candidate A's supporters rank
>Candidate C above Candidate B whom they detest, and B supporters also
>rank C second because of disdain for A, candidate C can win. Because the
>Condorcet winner may be someone who nobody considers a particularly good
>candidate, it punishes candidates who take clear stands on controversial
>issues and rewards candidates who say little of substance.
>Theoreticians must understand that the measuring tool (the voting system)
>can change candidate behavior and the information voters have for
>assessing them. The logic of Condorcet promotes a campaign strategy that
>is detrimental to political discourse and voters' ability to get the
>information needed to assess candidates. It primarily encourages avoiding
>alienating voters, and discourages taking stands on potentially divisive
>issues. Over a series of Condorcet elections we believe most major
>candidates would avoid taking clear policy stands, and in turn thus
>likely lead to lower voter turnout and less well-informed voters.
On this point I have multiple objections. The simplest objection is that
I simply don't think that polarized elections, and the polarized two party
structures which result, are a good thing. In fact I think that they're
terribly destructive. I think that our own political system is a dire
example of this. Democrats and Republicans not only disagree with each
other, but actually hate each other passionately, across the country. The
incentives are for the Democrats to do everything they can to make the
Republicans look bad, and vice versa. This is massively counter-productive
and leaves little room for compromise. I agree that IRV would maintain
more of the polarization of the plurality system than would Condorcet, but
I view this as a drawback rather than an advantage.
The next objection is to your assertion that Condorcet would favor
candidates who do not take stances on the issues. I don't think that it is
a fair assessment. I think that a more plausible statement is that
Condorcet favors candidates who stand with the median voter on the issues.
At this point I'd like to make a semi-digression which is closely related
to this point. I'd like to suggest that Condorcet may be more immediately
applicable for voting directly on issues than it is for voting on
representatives. I suggest that Condorcet-efficient methods would have the
potential to give us effective compromise solutions to social problems,
which would be far more valuable and productive than having two polar
options battling it out in an all-or-nothing conflict without a middle
ground.
For example, let's say that there was a ranked-ballot public vote in a
given state between three options:
1. Legalize gay marriage
2. Allow civil unions between same-sex couples
3. Allow neither civil unions or gay marriage
Let's say that the votes are cast as follows:
35: marriage > civil > neither
6: civil > marriage > neither
19: civil > neither > marriage
40: neither > civil > marriage
Use of IRV would result in the 'neither' option. A plurality vote would
also result in the 'neither' option and a single up-down vote on
legalizing gay marriages would fail. However, Condorcet reveals the civil
unions to be a majority-supported compromise. I think that Condorcet is by
far the best bet if you want to find effective compromise solutions,
provided of course that a sufficient compromise option exists on the
ballot.
Here's a similar imaginary example of an vote on three options:
legalizing marijuana, reducing penalties for marijuana use, and
maintaining the current penalties:
33%: legalize > decrease > maintain
16%: reduce > legalize > maintain
16%: reduce > maintain > legalize
35%: maintain > decrease > legalize
Again, in this example the 'reduce' option is a majority-supported
compromise, even though 'maintain' would win with both plurality and IRV.
I think that if we looked at public decision-making as a series of
compromises rather than all-out warfare between totally incommensurate
belief-systems, we would have a much healthier and more responsive
political system. So, whether or not you think that Condorcet should be
used to elect representatives, I hope that you will agree with me that it
should be used to tally direct votes between more than two options. Please
let me know what your thoughts are on this. My current proposal is for a
direct democracy system that incorporates proxy voting, is tallied by
pairwise comparison, and is legally non-binding while exerting strong
political influence. A draft of the proposal can be found at
http://fc.antioch.edu/~jarmyta@antioch-college.edu/voting_methods/proxy.htm
So, to come back to my earlier point, I believe that Condorcet would
support candidates who take a median stance, and indeed candidates who are
able to generate effective compromise positions, rather than candidates
who take no stance at all. All other things being equal (which they never
are, of course, but the point here is to illustrate a tendency), candidate
A will win her pairwise contest with candidate B if A's stance on a given
issue is median and B's is not. Surely no candidate could be expected to
have a median stance on absolutely every issue, but it is a good direction
to move towards.
The 40%-45%-15% example you gave to illustrate Condorcet's flaw is
implausible because in it there is no serious centrist candidate. In a
real Condorcet election which people actually wanted to win, there would
most likely be more than one or two contenders for the centrist position.
We wouldn't see two well-expressed wing candidates and a lone, skulking
stealth candidate; we would see several candidates seeking the political
center. And here I'm not talking about the center as an abstract notion
defined by pundits, etc. I'm talking about a democratic definition of the
center: the actual position of the median voter in an engaged electorate.
This would be a valuable process because it would give the nation an
opportunity to explore and seek its own political center. It would give
people an opportunity to try to move the center on a given issue by
gradual intervals, rather than in chaotic all or nothing bounds. I think
that one of the principle weaknesses of our current system is that it does
not enable us to know where our political center is, or to act from it,
develop it, to keep it flexible and responsive.
I think that an ideal PR system would achieve this, in that it would
provide representation for a wide diversity of viewpoints while allowing
the center to hold sway on each issue. I think that a good direct
democracy system would achieve this as well, as long as the tally system
was Condorcet efficient and effective compromise solutions were included
on the ballot.
So yes, a bland, inoffensive candidate would do well in Condorcet if his
only opponents were two wing candidates who were highly antagonistic to
one another, but that isn't a realistic situation. Actually there would be
multiple candidates attempting to define themselves into the political
center, show themselves to be effective problem solvers, demonstrate that
they are free from corruption, and gain the public trust. I think that I
as a voter would prefer a candidate who takes a stance on an issue that
isn't in line with my own and yet is reasonable and isn't at the opposite
extreme, to a candidate whose stance on that issue is unknown to me.
Basically I would be suspicious of the latter candidate, and I think that
most voters would share this sentiment. If so, then such a candidate
wouldn't stand a chance in a Condorcet election.
>IRV provides a better balance between the competing values of being
>representative of substantial numbers of voters and of having broad
>appeal. IRV encourages candidates to distinguish themselves and to have
>sufficient boldness to win many first-choice rankings, but it also
>encourages candidates to reach out to supporters of other candidates and
>avoid vilifying them in overly negative attacks. This is a desirable
>incentive package.
>A voting system does not just select winners. A voting system shapes the
>nature of political debate, and largely dictates how well informed most
>voters are able to be. An inoffensive candidate who studiously avoids
>taking any controversial stands, but simply campaigns by projecting an
>image of being friendly and honest can be everybody's acceptable
>compromise and win with Condorcet even if nobody considered him/her the
>best candidate. While plurality voting over-values the ability to be a
>voter's first choice, Condorcet overvalues the value of ability to avoid
>being voters' last choice. IRV provides a compromise by giving
>appropriate weight to both values.
I have two objections to the 'strong support versus broad support'
argument. The simplest is that it is theoretically possible for a
candidate to be a Condorcet winner as well as having the most first choice
votes, and yet to lose in IRV. For example:
17%: far right > right > center > left > far left
18%: right > center > far right > left > far left
16%: center > right > left > far right > far left
16%: center > left > right > far left > far right
17%: left > center > far left > right > far right
16%: far left > left > center > right > far right
So the first choice votes are as below, and subsequent choices never skip
a place on the spectrum.
far left left center right far right
16 17 32 18 17
In this example the center candidate is the first choice of by far the
most voters, wins all of his pairwise comparisons with great ease, and yet
'right' is the winner in IRV.
This is something of a side point though, as your assertion that IRV
places more importance on first choice votes than Condorcet is generally
correct.
My deeper argument against the 'strong support versus broad support'
argument does not rely on such examples at all, but rather questions
whether a first choice vote necessarily indicates 'strong support', or a
second choice vote necessarily indicates 'weak support'. My belief is that
such assertions simply cannot be made, as there is no inherent utility
value or emotional value to the different ordinal places on a ballot.
Instead, I believe that the position of one candidate on a ballot only
derives significance from its relation to the position of other
candidates. This is why I believe that the pairwise count method is
indispensable. Over the summer I wrote a brief essay which attempts to
drive this point home. The writing could use an overhaul, but nevertheless
in case you're curious the essay can be found in its current form at
http://fc.antioch.edu/~jarmyta@antioch-college.edu/voting_methods/value_of_first_choice.htm
In closing, I'll say that I imagine Condorcet to have been something of a
hero, a genius with a good heart who was killed by the Jacobins because he
was forthright about his beliefs and cared more about truth and social
progress than about making the right move politically. I would like to
honor his memory by treating his ideas with the respect they deserve, and
I look forward to a time when society will be ready for them.
Sincerely,
James Green-Armytage
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