Re: Constitutional amendment: Condorcet/Clone Proof SSD vote tallying
On Tue, May 20, 2003 at 05:58:10PM -0500, Manoj Srivastava wrote:
> Oh, as a sponsor of the GR, I suppose I should clarify that I
> am not going to accept this amendment; I consider it a bad one. This
> makes our vote method fail the monoticity criteria
> (http://www.electionmethods.org/evaluation.htm). See Scenario 2 below.
Sorry, yet another follow-up. This still bothers me.
> Scenario B:
>
> Consider the case where the quorum is 45, and there have been
> 44 votes -- 23 for, 21 against. (Only one option on the ballot). I am
> opposed to the option.
>
> At this point; under my version; I can express my opinions
> with no fear of harming my candidate. Under your amendment; if I do
> not vote; the vote is nullified. However, if I vote against the
> option -- the option shall win!!
[...]
> With the relative order or rating of the other
> candidates unchanged, voting a candidate higher should
> never cause the candidate to lose, nor should voting a
> candidate lower ever cause the candidate to win.
I think this is talking about changing an existing vote, not casting an
extra one. Thus it's irrelevant to your example. All of the examples on
the URL you gave are about changing votes, not adding more. Further,
some other URLs I found define the monotonicity constraint as:
"If an election is held and a winner is declared, this winning candidate
should remain the winner in any revote in which all preference changes
are in favor of the winner of the original election."
- http://www.ctl.ua.edu/math103/Voting/whatdowe.htm
"Changing your vote so as to vote someone higher should never make him
lose when he'd have otherwise won. Changing your vote so as to vote
someone lower should never make him win when he'd have otherwise lost."
- http://www.barnsdle.demon.co.uk/vote/akadem.html
"Monotonicity criterion. If one set of preference ballots preference
ballots would lead to an an overall ranking of alternative X above
alternative Y and if some preference ballots are changed in such a way
that the only alternative that has a higher ranking on any preference
ballots is X, then the method should still rank X above Y."
- http://www.csc.vill.edu/faculty/bartlow/html/mat1220/arrowthm.html
Adding additional votes is not the same as changing additional votes.
Common sense would seem to suggest that if the vote changes from
23/21 to 23/22, for should win, anyway. Against was never going to
win. The extra vote didn't make the for case win - it simply made
the entire ballot valid.
I have serious concerns about this ballot. John Robinson's proposed
amendment has been rejected by Manoj so according to the constitution it
should be voted on. Further it seems to address some real problems in
the new proposed system.
Hamish
--
Hamish Moffatt VK3SB <hamish@debian.org> <hamish@cloud.net.au>
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