At 03:13 PM 5/17/2010, Kevin Venzke wrote:
Hi Warren,
--- En date de : Lun 17.5.10, Warren Smith <[email protected]> a écrit :
> I just started looking in the library
> to answer the historical
> question "what did Condorcet himself (and other authors
> about
> Condorcetness) have in mind?"
>
> Albert Wiele: "Democracy," St Martins Press NY 1999
> on p133 defines "A condorcet-winner is that alternative
> that could
> defeat every other alternative in a pair-wise contest."
> Note: this can be interpreted as saying "range voting is a
> condorcet
> system" or "not."
>
> It is ambiguous.
It's only ambiguous if he didn't define "pair-wise contest." Did he?
Personally I know what I mean when I say "pairwise contest" and it
doesn't concern me that if I spoke less precisely then something else
could be understood.
Here is the issue. Is the "pairwise contest" some
*other election*, where the two candidates face
off against each other? But this is a completely
different election! It's a theoretical construct,
not an actual procedure to follow with ballots.
The question is whether the ballots are changed!
If the original election ballots have:
51: A 6, B 5
49: A 0, B 10
Who wins that "pairwise election?" Surely it
depends on the rules! But it was assumed that
preference was the information provided:
51: A>B
49: B>A
A wins, no doubt about it (if plurality is the
rule, and in this case, it's even a majority.).
The idea that only preference information is
extracted from the ballots in order to construct
this "pair-wise contest," neglects much election
reality. The idea that Range fails the Condorcet
Criterion is based on an assumption that the
internal preferences will remain the same in this
"pairwise election," not that the pairwise
election is determined by ignoring all other
votes from the full election (Range, in this
case). Since we can see that 51% of voters prefer
A to B, we assume that they will vote this way.
But in real elections, they might not vote at
all, so weak is their preference. Easily, if we
took that pairwise election and did actually run
it -- and I've proposed exactly that, we could
find that B wins the runoff. I predict it, except
in one case, where the A supporter votes were
distorted by some artifact, perhaps the presence
of some irrelevant candidates that seriously
distracted the 51%. (I'm assuming that A and B
are indeed the frontrunners, there may be massive
vote splitting among the favorite and worst as seen by the 51%.)
No, where a ballot does allow full preference
expression, and Range of sufficient resolution
does that, I see no problem with asserting that
Range will always pick *by definition* the
Condorcet winner, and it isn't troubled by cycles
(only by the much more remote possibility of ties.)
What is truly offensive is when both the Range
and Condorcet winner, by true preferences and
strengths, lose, because of quirks of a voting
system like IRV. I.e., assume true preferences
(with or without normalization, and it's most
offensive when the utilities are normalized),
derive sincere votes from them in a Range method
of sufficient resolution to express all
preferences, and the Range winner and the
Condorcet winner are the same (as will normally
happen), but this candidate loses in, say, IRV,
because of insufficient first preference votes,
so the candidate is eliminated before a strong
showing for second rank appears (which could even
be unanimous, a truly good outcome), whereas the
IRV outcome, in theory, could be strongly opposed
by two-thirds of the voters. (That's extreme, of
course, but it's not hard to understand center
squeeze and, in fact, it's quite predictable when
there are three major parties.)
For the long term, I'm suggesting implementing
methods that collect Range data, but always
including a Condorcet winner apparent from the
votes in a runoff, if a runoff is needed. Then,
ultimately, efficient voting systems can be
designed based on real election data. I'm
suggesting Bucklin as the method, using a Range
ballot with 50% rating being approval cutoff, no
candidate would be elected in a primary unless
they have at least a majority of voters rating
them at 50% or higher. As a Bucklin method, it
would be clearly Majority criterion compliant.
But it is possible that it could miss some minor
Condorcet winners, due to multiple majorities
appearing in a Bucklin counting round. That's a
relatively harmless Condorcet violation, and my
guess is that it would be rare. But good ballot data would show it.
And as to the runoff, I just point out that it
could be arranged that a condorcet winner would
always be included. So we actually would have
that real pairwise contest! My theory would be
demonstrated or shown to be bogus. In fact, I
expect that *usually* the Range winner would
prevail, but I've also noted that exceptions
could exist due to unwise exaggeration or
normalization error in a primary. In other words,
the Range winner only *appeared* to be the
utility maximizer due to quirks in the voting.
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