Hello
On Mon, Dec 09, 2002 at 03:20:20AM +1000, Anthony Towns wrote:
> Can we possibly stop coming up with full blown voting systems while
> we still don't have a firm idea of the underlying things we're trying
> to achieve?
Good idea :-)
> (1) We want a voting system that handles quorums.
> (1a) Quorums are handled on a per-option basis.
> (1b) Electors are counted toward the quorum if they vote, and if they
> rank the option above the default option.
Can you give reasons for (1a) and (1b)? As far as I
understood the debate, the reason for a quorum is to avoid
"stealth-decision-making", i.e. to assert that enough
developers notice the election and take part in it. Because
of this for me the concept of a per-option quorum does not
make much sense. What do you think?
Some other goal I would propose:
(3) In the absence of a quorum/supermajority requirement our
voting system should behave identical to textbook Condorcet
voting with Cloneproof Schwartz sequential dropping.
This may be clear (is it?) but I think that some of the
previous drafts did not have this property.
And finally: the reason way we want Condorcet voting is,
that this system is a "good" voting system in the sense of
http://electionmethods.org/evaluation.htm
I append a list of good properties of Condorecet voting
below (summarized from the election-methods page). To
handle quorum and supermajority requirements we have to make
changes to the voting system. In my opionion we should find
out which of the properties we loose because of the changes.
Remember: these properties were the reason why we want
Condorcet voting instead of competing systems.
What do you think?
Jochen
A list of good properties of Condorcet Voting
(from http://electionmethods.org/evaluation.htm)
* Monotonicity Criterion (MC):
If a single voter changes his mind and ranks an option higher,
this option can not stop being the winner because of this
* Condorcet Criterion (CC):
If one candidate is preferred over each of the other
candidates, that candidate is the Ideal Democratic Winner
(IDW). If all votes are sincere, the Ideal Democratic
Winner should win if one exists.
* Generalized Condorcet Criterion (GCC):
If all votes are sincere, the winner should be a member
of the Smith set.
^^^^^
this is what we call "Schwartz set".
* Strategy-Free Criterion (SFC):
If an Ideal Democratic Winner (IDW) exists, and if a
majority prefers the IDW to another candidate, then the
other candidate should not win if that majority votes
sincerely and no other voter falsifies any preferences.
Note: sometimes (When good options are ranked equal) and
IDW can be not preferred by a majority of voters over
another candidate.
* Generalized Strategy-Free Criterion (GSFC)
If an Ideal Democratic Winner (IDW) exists, and if a
majority prefers the IDW to another candidate, then the
other candidate should not win if that majority votes
sincerely and no other voter falsifies any preferences.
* Strong Defensive Strategy Criterion (SDSC)
If a majority prefers one particular candidate to
another, then they should have a way of voting that will
ensure that the other cannot win, without any member of
that majority reversing a preference for one candidate
over another or falsely voting two candidates equal.
This seems to be a weaker form of what we want to achive
with supermajority requirements.
* Weak Defensive Strategy Criterion (WDSC)
If a majority prefers one particular candidate to
another, then they should have a way of voting that will
ensure that the other cannot win, without any member of
that majority reversing a preference for one candidate
over another.
Condorcet voting with Cloneproof Schwartz sequential dropping
additionally has the "cloneproof" property (from
http://electionmethods.org/CondorcetEx.htm)
* The Schwartz Sequential Dropping (SSD) method has a
``plain'' version and the ``cloneproof'' version. The
cloneproof version gives no group or party any advantage
or disadvantage for having additional candidates that
are essentially ``clones'' of each other. Except for
the case of ties, the two versions give the same result.
--
Omm
(0)-(0)
http://www.mathematik.uni-kl.de/~wwwstoch/voss/index.html
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