On Wed, 27 Jul 2005 16:01:16 +0200 (CEST) Kevin Venzke wrote:
Dave,
Please give an example, but:
No IRV - let that be a separate project.
No cycles - likewise, unless you state that there is no problem
without cycles being involved.
When no cycles are involved, Condorcet is 100% perfect. So I have to use
examples with cycles:
Fine, so the voters are offering cycles - at least 3 conflicting opinions
- to become a problem.
--- Dave Ketchum <[EMAIL PROTECTED]> a écrit :
My comparison of methods:
Approval - its backers like to brag, but it is not that simple -
unlike Condorcet and IRV, voters CANNOT say: I prefer Nader but, only if
I cannot have Nader, give me Kerry as better than Bush.
However, ranked methods won't always obey your request. Condorcet methods
and IRV will both sometimes take the vote "Nader>Kerry>Bush" and elect Bush,
when if you had instead not ranked Nader, the method would elect Kerry. That
is, the method ignores the fact that you said "If I cannot have Nader, give
me Kerry."
77 A>B>C
57 B>C>A
145 C>A>B
143 C=B>A
80 A>B>C
WV methods elect C. But if the 80 A>B>C voters instead lower A anywhere below
B, then the winner is B. So the methods ignore these voters' wish that B be elected
if they can't get A.
Huh? When they SAID they preferred B, they GOT B.
However, when they said they preferred A, they were a minority part of a
cycle in which major desire for C won. They did not get ignored - simply
were too small a minority to win.
Condorcet methods will sometimes see the "give me Kerry as better than Bush"
part and give the win to Kerry, when it could have gone to Nader otherwise,
despite the fact that your vote says "ONLY if I cannot have Nader, give me
Kerry."
On these ballots:
49 Bush
24 Kerry>Nader>Bush
27 Nader>Kerry>Bush
WV methods (actually, all Condorcet methods) elect Nader. But if the 24 voters
just vote "Kerry," with no preference for Nader, then the winner is Kerry. So
the methods ignore the 24 voters' request that they get Nader ONLY if they
can't have Kerry.
A simpler set of votes, with no cycles.
Conceded that if the 24 were part of liking Nader, even without liking
Nader best, they got Nader.
Now try an IRV example:
49 Bush
24 Kerry>Nader
27 Buchanan>Nader
Now Bush wins, while liked less than Nader, for:
The 24 ballots get looked at and discarded.
Bush wins over Buchanan.
IRV ignores the 27 votes for Nader, without noting their existence -
while Condorcet would have seen that Nader earned a win.
My point is that, at least with approval voting, the voter knows the limits of
how the method will use his ballot. With ranked ballots one can't be sure that
the method won't pick and choose what information to use, or even (in the
first example) use the information to elect the ballot's last choice.
With approval I cannot SAY I like Nader, Kerry, and Bush, in that order.
With Condorcet I can rank, and get my ballots read, though minority votes
properly rank below majority votes.
With IRV I usually do the same as with Condorcet, though IRV can and does
ignore parts of some ballots, and has a different solution when Condorcet
would see a cycle in a near tie.
NOTE - perhaps we are stumbling over language. If the voter simply lists
the candidates according to preference the results will please many.
Kevin Venzke
--
[EMAIL PROTECTED] people.clarityconnect.com/webpages3/davek
Dave Ketchum 108 Halstead Ave, Owego, NY 13827-1708 607-687-5026
Do to no one what you would not want done to you.
If you want peace, work for justice.
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