On May 15, 2010, at 7:17 PM, Kevin Venzke wrote:
Hi Dave,
--- En date de : Sam 15.5.10, Dave Ketchum
<[email protected]> a écrit :
De: Dave Ketchum <[email protected]>
Objet: Re: [EM] Why Not Condorcet?
À: "Kevin Venzke" <[email protected]>
Cc: [email protected]
Date: Samedi 15 mai 2010, 17h34
On May 14, 2010, at 7:08 PM, Kevin
Venzke wrote:
Dave, by the way,
--- En date de : Ven 14.5.10, Dave Ketchum
<[email protected]>
a écrit :
We can dream of value in details as we sit here
and
debate. Real-life voters need a way to
express their
most serious thoughts with reasonable effort:
To vote for more than
Plurality's
one - which even Approval offers.
To vary their approval
according
to their amount of liking - Condorcet and Score
offer this.
To ask for only reasonable
effort
from the voters - see Condorcet.
Score demands more. A
voter
thinking of A>B>C>D has no trouble
offering min and
max ratings to A and D. With
Score the
voter is expected to diligently assign the
available rating
space among A>B, B>C, and C>D.
I notice that all of your arguments have to do with
the expressiveness
and simplicity of the ballot (except when you
criticize IRV).
Some objections to Condorcet could be:
1. It is not expressive enough (compared to ratings)
Truly less expressive in some ways than ratings.
This is balanced by not demanding
ratings details.
And more expressive by measuring
differences between each pair of candidates.
That is probably the argument I would make more often. Ratings has
no interest in pairwise contests, which makes its behavior (and ideal
voter behavior) very different from Condorcet methods'.
2. Offensive strategy potential (absent in IRV,
ratings, Bucklin)
How is IRV different?
In IRV your lower preferences are not regarded until all higher
preferences are eliminated. This means it is completely impossible to
make your favorite candidate win by lying about your lower
preferences.
AND, by your choice of higher preferences in IRV, you can prevent your
lower preferences from ever being seen.
Perhaps more importantly: It's also impossible to try to do this and
fail so badly that you elect a candidate no one likes.
3. Lacking guarantees (e.g. FBC or LNHarm)
Isn't this standard among methods
- each with different details?
Yes, but different people will value different guarantees.
4. Too complicated to explain, or propose (a
conceptual hurdle with
Condorcet is that we leave the actual ballots for the
pairwise matrix
right away, making it hard to understand how voting
different ways
could change things)
Some Condorcet methods of handling
cycles are truly complex - I recommend choosing a method for
which cycle explaining is doable.
Counting into the matrix should
class as understandable.
It's possible. I do think it would be helpful if Condorcet could be
defined in terms of how a single ballot "goes through the process." In
essence Condorcet sucks all the data out of the ballots like a
vacuum and
finds the best winner without thinking about which ballot said what.
This
makes for a pretty good method but it's also what means Condorcet
provides
relatively few concrete guarantees to the individual voter.
It is true there is no record, except for the ballot, as to which
voters contributed to each pair.
In Condorcet every pair of candidates competes. From each ballot
every candidate ranked gets counted among the pairs:
Among ranked pairs, if ranked higher than its competitor.
Against other candidates, simply for being the one ranked of the
pair.
Usually one candidate will win, as CW, for winning (I am assuming
margins, and assuming no ties) in each of its pairs. This is partly
that some candidates are liked more than others, and partly that
Condorcet treats all said on each ballot as having equal value.
Next possibility is a 3-member cycle among the best liked - each
member beats one other and is beaten by one other - deciding which
wins is based on which solution method is used.
More complex cycles are possible, but expected to be rare.
5. Not thought to be politically acceptable (third
place in FPs can win)
You seem to be complaining about newness - a problem for
any new thought until/unless accepted.
I'm not complaining at all, I'm suggesting reasons of others. The
problem
could very well just be newness, but IRV for instance has this
problem a
little less than Condorcet.
IRV has backers SELLING - some of us complain that they do not require
truth as a basis for their selling
Kevin Venzke
Dave Ketchum
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