[EM] [CES #4429] Looking at Condorcet

[robert bristow-johnson]

On 2/1/12 11:28 PM, Jameson Quinn wrote:
> Dave gives good reasons for Condorcet. I'd like to present the other 
> side.
>
> Condorcet systems have many advantages. So what's wrong with Condorcet?
>
> It comes in a bewildering array of forms, thus reducing the unity of 
> its supporters. But that's not the real problem.
>
> It admits both betrayal and burial strategy, thus encouraging 
> dangerous, negative-sum strategizing from its voters. And that could 
> be significant. But I think that voters will realize that they will 
> almost never have the information and unity to pull off a successful 
> strategy, so that's not the real problem.
>
> It is complicated to understand, and impossible to easily visualize, 
> how it works.
i disagree with that.  i spelled that out (how you would spell it out to 
the average voter) in my just previous post.

Condorcet is *simple* to understand.  unless there is a cycle, no one 
should be disputing the CW outcome.  the weak-CW with few 1st-choice 
votes is not a strong case.

you elect the CW, because of the inverse consideration.  if you elect 
someone other than the CW (as we did in Burlington 2009), you are 
electing a candidate when *more* of us voters marked explicitly on our 
ballots that we preferred someone else.  *not* merely someone else in 
general (the "anybody but Jack" vote), but we voter said specifically we 
want Jill instead.  how can it be a democratic decision when more of us 
choose Jill elected to office over Jack than those who choose Jack over 
Jill, yet Jack is elected despite the mandate from the voters?  i have 
never seen an adequate answer to that.  in a simple 2-person race, even 
if the vote margin is close, even if by *one* vote, if more of us want 
Jill than those of us who want Jack, then Jill is elected.  would you 
have it any other way?

if you would not have it any other way, you cannot make a consistent 
argument against electing the CW if there is one.  but we can argue 
about what to do about cycles.

> But that's not the real problem.
>
> As a ranked system, it is hopelessly caught in the contradictions of 
> Arrow's theorem.

sure, and that's the case for any system.  but it's less of a problem 
than the demonstrated problems (not mere theoretical issues with Arrow) 
of either IRV (as demonstrated in Burlington 2009) or FPTP (myriad times 
when there are spoiler candidates, which might happen in Burlington in 1 
month).

the *only* problem (a la Arrow) that i see with Condorcet is the 
potential of a cycle.  but it won't happen often and only when the three 
top candidate all have roughly equal support.  it's the same kind of 
problem as a tie, and you create rules to deal with that difficult 
situation in some kind of sense that makes sense (and i'm not saying 
that there is a clear winner in which cycle-resolving method makes the 
most sense, but since a cycle is even less likely to involve more than 
three, it's really a moot question).

> But that's not the real problem.
>
> Some voters will mistakenly imagine that it's Borda. But that's not 
> the real problem. (They'll imagine that MJ is Range, too. I don't see 
> how they'd significantly misapprehend SODA, though.)
>
> The real problem is that I think that people just don't want to do 
> that much work to vote. Yes, I know, you can just vote approval-style 
> if you want to, but most people would feel guilty about not really 
> doing the whole job then.

what people don't want to do is to agonize over how to vote to serve 
their political interest when there are multiple outcomes, only one of 
which is the voter's hearts desire.  there often is another outcome 
which is tolerable and another that is intolerable.  what should the 
voter do to be counted among those against the intolerable outcome, yet 
still support his/her sincere favorite candidate?

that is the real problem, Jameson.  i don't think feeling guilty is a 
problem.  but voter regret is, especially after helping elect someone 
like George W Bush to office because one voted for Ralph Nader.  that, 
in a nutshell, is the problem.

> I honestly think that honest rating is easier than honest ranking. 
> (How's that for honesty per square word?) MJ is the only system which 
> allows honest rating to be full-strength in practice; and SODA is the 
> only good system which allows anything easier. (And no, approval is 
> not easier than MJ, because approval forces some amount of strategizing.)
>
> Most voters are lazy. And they'll resent any system which rubs their 
> nose in that fact. Which Condorcet does.
>
i don't see that.  it's no worse than IRV, which is

               "as easy as 1-2-3!"  :-)

ranking is not hard.  Condorcet does not ask anything more from the 
voter, lazy or not, than does IRV.  all it requires is for the voters to 
make up their minds about the candidates by Election Day.  how is that 
an unreasonable expectation of voters?


> (SODA, on the other hand, brings lazy voters together, and gives their 
> representative as much negotiating power as possible without diluting 
> the winner's leadership mandate.)

my issue with SODA is only that regarding any* non-Condorcet method.  if 
SODA does not elect the CW, if IRV does not elect the CW, if Borda or 
Bucklin do not elect the CW, then we are electing a candidate to office 
when more voters explicitly preferred (as marked on their ballots) a 
different *specific* candidate.  how is that democratic?

L8r,

-- 

r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."