Condorcet analysis of Official PEP308 Ballots

Anders J. Munch andersjm at dancontrol.dk
Wed Mar 12 10:49:26 CET 2003


"Norman Petry" <npetry at accesscomm.ca> wrote:
> On Tue, 2003-03-11 at 09:59, Anders J. Munch wrote:
> > "Norman Petry" <npetry at accesscomm.ca> wrote:
> > > 
> > > http://24.72.22.210/pep308ballots.html
> > > 
> > > The Condorcet results for this set of ballots are shown at the end of
> > > this message.
> > 
> > Interesting ... but unfortunately the premise for the Condorcet method
> > is not met.  Since voters haven't ranked the candidates in order of
> > preference you cannot really say to have found the Condorcet results.
> 
> No and Maybe.  Voters have been allowed to provide _limited_ rankings on
> the official ballot, so it's not correct to say that voters "haven't
> ranked the candidates in order of preference" -- they clearly did. 
> Unfortunately, a lot of voter preference information was lost due to the
> limit placed on the number of options that could be ranked (3).
> 

I apologise for having expressed myself unclearly.  Condorcet requries
a full ranking and the official ballot results are not full rankings,
so you can't find the Condorcet winner.  Only if you add an assumption
about what the missing ballots said, then you can find the Condorcet
result under those assumptions.

The assumption that I gather you made is that all voters ranked the
remaining entries equally.

Another interesting possibility is to find the Condorcet results that
would hold regardless of what the missing ballots said.  I suspect
that NO CHANGE and C are possible Condorcet winners, but none of the
others are.

- Anders






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