[EM] Draft of CVD analysis about IRV vs. Condorcet Voting

[James Green-Armytage]

This is James Green-Armytage responding to Ken Taylor

>James wrote:
>> However, there is no question that the strategic possibility is there,
>> and so I think that your note is unfortunately quite wrong. If after
>> reading my August posting you no longer hold to your earlier statement,
>I
>> would suggest that you send another e-mail to CVD to concede the point.
>I may have worded my response to the article too strongly. However, your
>example, reposted here:
>46: A>B
>44: B>C (instead of B>A)
>5: C>A
>5: C>B

	Please note that there is a second example at the end of that posting;
one which is stronger in that it is harder to deal with.
>
>does not show what I wrote to be "quite wrong." In fact, it basically
>demonstrates my point that "At best, this insincere ranking will create a
>cycle in the result -- and then the strategic advantage depends on the
>cycle-breaking method." 

	Yes, but that's just it. No matter what the cycle breaking method is, it
will under some circumstances reward those who have strategically created
the cycle to begin with. Your argument is dependent on this point, and
since you are wrong on this point, your argument is wrong.

>The only point I was incorrect on was stating
>parenthetically that SSD with magnitude dropping was immune to this
>strategy -- as your counterexample shows, it is not. However, other
>methods
>can be used to resolve the cyclic anomalies which are immune to this
>strategy. 

	No. All completion methods have serious strategical vulnerability such
that they provide incentive to create a fake cycle.

>The original article even suggested using IRV in these cases,
>which is immune to this particular strategy. 

	The strategic incentives in Condorcet-completed-by-IRV are still very
substantial. Basically the incentive is for people who favor a candiate
who is the IRV winner but not the Condorcet winner to strategically alter
their ballots so that no Condorcet winner emerges. Comparing this
strategic liability to the strategic liability of SSD is apples and
oranges: they are both serious, but in different ways.

>Therefore, under the
>assumptions of the original article, this strategic problem *doesn't*
>exist
>with condorcet, and I do not have to concede my point. I will write
>another
>email to the author of that article noting that my parenthetical statement
>about SSD was incorrect, however.

	See above. The whole argument depends on the parenthetical statement.

>(A question for other readers of electionmethods: are there better cycle
>breaking systems than SSD which are more immune to strategy?)

	More or less, it's possible. But there are no methods that are immune
enough to stop it from being a serious concern.

>> I have to say that if you send them e-mails touting faulty arguments,
>you're
>> making Condorcet supporters look bad. I've read the CVD e-mail, and
>there
>> are effective counter-arguments to it, but that's not one of them. I
>wish
>> that Condorcet didn't have that strategy problem, but it does. Please,
>> let's not dismiss the CVD people as a bunch of idiots or villains. I
>agree
>> that it's an awkward situation where they control the lions share of the
>> public attention and donation resources toward voting methods reform and
>> yet are kind of lazy when it comes to voting methods theory. However, in
>> this case they have taken at least a little bit of time to think about
>it,
>> and many of their arguments are relatively sound, so just blindly
>bashing
>> at them is unfair and unproductive. I'm sure you meant well, and I'm
>sorry
>> to come down on you, but let's look before we leap, okay?
>I find this entire section of your message to be quite inappropriate. It
>is
>riddled with incorrect assumptions about me and is quite patronizing.. 

	So it is. I apologize for making assumptions about your relationship to
CVD and IRV.

>I don't represent, and don't claim to represent, "Condorcet supporters"
>as a
>whole. I don't make them "look bad" simply because I made a small factual
>error in my argument. 

	Again, the error is not a small one.

>I don't dismiss CVD as "idiots" or "villians" 

	No, you're right. That was a false assumption of mine.

>-- in
>fact, my email to the author (of which I only reproduced a small part
>here)
>was intended to help him improve his article before publishing -- he even
>wrote back to me stating that my comments were helpful and that he'd
>probably implement some of my suggestions. 
>I am not "blindly bashing" them,
>and I have "looked" before I "leaped." 

	I disagree that you have looked as carefully as I think you should when
making strongly worded arguments such as the one you sent. As for "blindly
bashing", it just seemed that way to me because you didn't understand the
argument in full before you attacked it. That's what I meant by "blind."
As far as "bashing," well, maybe you weren't really bashing.
	It just seemed strange that you picked the most valid part of the CVD
argument to take issue with, when there are in fact much stronger
counter-arguments to be made. It seemed like sort of a chaotic move. I
guess it's not really my business to tell you who to write e-mails to and
what about, but you did invite criticism, and that's what I thought.

>In fact, it may even suprise you to
>learn that I actually *support* IRV and *applaud* CVD's efforts on the
>political front. I believe condorcet is a better system overall, but I am
>not a member of this supposed "CVD is evil" zealot crowd.

	My mistake.
>
>Please, refrain from making such presumptions about people in the future.
>Or
>at least refrain from commenting on such presumptions, and instead
>concentrate on the *arguments* that are actually made.

	Well, I did that too. So yes, let's focus on the argument itself from now
on. I still hold that your argument was incorrect, save for its
implication that the CVD people should research the different completion
methods rather than lumping them together, which they should indeed. But
whichever completion method you use, the incentive for the "burying"
strategy is still there, and still a major issue.


James