[EM] IRV vs. Condorcet

[James Green-Armytage]

Dear Kevin, replying to your reply, 


>This is how I feel, incidentally.  I'm afraid the IRV/Plurality question
>is a
>little boring for me.

	As far as the technical side goes, I don't find the IRV / Plurality
question to be especially interesting either, because I think that it's
obvious that IRV is better.
	What is more interesting to me is the question of what an actual voting
systems movement could look like in the US, or any other country. And a
big part of that is the relationships between people who favor different
systems; the extent to which they are able to cooperate. That hinges on
whether they can find some kind of common ground, and I am suggesting that
there is a common ground in their critique of the plurality system.
	So I am not expecting the technical question to be a charged topic for
debate. I am expecting that we can come to an easy consensus that IRV is
better (technically, at least) than plurality. 
	And even though it may not seem like much, that little bit of common
ground may be meaningful. Or at least it is meaningful in my cockamamie
version of reality. Perhaps some people on this list aren't interested in
trying to build a public movement around these issues, but I am; I think
that that is a natural extension of finding out that a better way of doing
something exists. 



>There is a possibility that low-utility CW's wouldn't win in Approval. 
>I'm not
>sure if that is "normative."  (Perhaps someone knows of more reasons.)

	Perhaps I wasn't being very clear by saying 'normative.' What I really
meant by a normative argument was an argument dealing with how things
should be rather than how likely it is that they will be that way...
therefore, an argument for Approval over Condorcet that doesn't rely on
things like ease of implementation. Like technical vs. practical, or
however you want to call it.
	As far as that goes, your point fits into the category that I was looking
for. Although I can't say that I find it very convincing. I think that a
Condorcet winner is a Condorcet winner, and should be elected. I doubt
that there is a method that is strategy-free enough for public elections
that will tell us how much utility a candidate has. Also I see no
guarantee that approval will exclude a low utility candidate.

I imagine that you have in mind an example something like this, right?
48: A>>>>>B>C
3: B>A=C
49: C>>>>>B>A

Despite all of those little carrots, I can't really see how it's justified
for anyone other than B to win here, assuming that majority rule is what
you're after. If you give it to A, the plurality winner and IRV winner,
then all the people who voted A>>>>>B>C will cry hey! And they will want
to change their vote to A>B>C, or B>A>C, or whatever, depending on what
weird method you are using that doesn't pick B. And if they are allowed to
change their vote, then B will win, sure as pudding. If they can't, then
they will regret their votes.


>> 	However, I am admittedly not totally convinced that Approval is
>superior
>> to IRV. (It may well be, but nobody has convinced me of it yet.)
>> 	Also, I think that a version of IRV that allows for equal rankings
>would
>> be better than plain IRV, and would incorporate many of the virtues of
>> Approval, with the added freedom of voters to differentiate between
>levels
>> of support. Aside from monotonicity, I would like to know what other
>> advantages Approval has over 'equal rankings' IRV. 
>
>I do believe strategy would be more difficult in the latter.  A clueless
>voter
>(such as one who who prefers to strictly rank) might be significantly
>disadvantaged.

	I'm not entirely sure that I understand what you are referring to, but
maybe I do. Strategy is more difficult in equal rankings IRV than
approval? Hmm, maybe so. But I think that there is a lot of strategic
thinking that goes into approval. 
	Approval seems to me to be the only method we discuss that *requires*
voters to think strategically. That is, if you assume that voters have
sincere preferences that are essentially in ranked order, they have the
option of an entirely sincere vote on any ranked ballot method (or, at
least, any method that allows equal preferences, if you imagine that some
people are indifferent between two or more outcomes). However, approval
seems to require some sort of strategic thinking as to where you choose to
place your approval cutoff on your sincere ranked list. 
	For that reason, I think that the results of approval voting are
unpredictable. And for that reason in turn, I think that it will be
impossible to fairly assess approval voting until it has already been put
in practice in a good number of places and situations.
	Hmm, maybe I am overstating my case a little bit here. I suppose that
people's approval cutoff could be more a matter of sentiment than
strategy... Maybe I should say that there is always incentive for strategy
in approval, but there is only incentive for strategy in Condorcet in
special cases?
	Anyway, I would like for an approval fan to really lay out why they think
approval is so effective. I know that there are some very smart people who
are approval fans, so I imagine that there must be something to it. But at
this point, I don't know what that something is, exactly.


>
>What do you think about MCA?  The odds of electing a majority favorite
>are 
>increased.

I'm sorry to admit that I'm not wholly clear on what MCA is.


thanks for your reply!
	James