[EM] Comments on Nanson & Condorcet Criterion.

[MIKE OSSIPOFF]

Someone wrote:

The election method which is an elimination method based on the Borda count
   is usually known as Nanson's method. It has the very nice property that 
if
    there is a condorcet winner that the method chooses that candidate.

I reply:

If we use "Condorcet winner" to mean a candidate who, when
compared separately to each of the others, is voted over him
by more voters than vice-versa, then Plurality meets that criterion.

The Condorcet Criterion can be worded in terms of a sincere
Condorcet winner (a candidate who, when compared separately to
each one of the other candidates, is preferred to him by more
voters than vice-versa):

If there's a sincere Condorcet winner, and everyone votes sincerely,
then the sincere Condorcet winner must win.

That wording has the advantage that Plurality doesn't pass, but
some methods do pass.

Obviously a Condorcet Criterion wording that doesn't have those
properties isn't very useful.

So the Condorcet Criterion stipulates sincere voting by everyone.
Good luck :-)  That's why the Condorcet Criterion doesn't seem
to be very useful, even when worded in a usable form. FBC,
SARC, WDSC & SDSC offer absolute guarantees to the voter, without
any stipulations. SFC & GSFC only stipulate that no false preferences
are voted, which is a less demanding stipulation than sincere
voting, which, with a rank method, means sincerely ranking all of
the candidates, and forbids truncation.

By the way, I'd like to add that the Smith Criterion,
Condorcet Loser, Majority Loser, & Mutual Majority, all
need to be fixed in the way that Condorcet's Criterion needs to
be fixed, in order to be meetable, but not met by Plurality.

Mike Ossipoff


_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.

Share information about yourself, create your own public profile at 
http://profiles.msn.com.