[EM] Consistency, Truncation, etc. (was CR ballots, etc.)

Buddha Buck bmbuck at 14850.com
Tue Sep 25 21:47:54 PDT 2001

Forest Simmons <fsimmons at pcc.edu> writes:

> On Mon, 24 Sep 2001, Jobst Heitzig wrote:
> > On 24 Sep 2001, Buddha Buck wrote:
> > 
> > > Hmm...  I'd love to see an example of this, since I fail to see how it
> > > could happen.  
> > > Therefore, the Condorcet Criterion is not
> > > inconsistant.
> > 
> > Sorry about that: you are of course completely right! Condorcet methods
> > can only be inconsistent in cases where some of the groups lacks a
> > Condorcet winner.
> In other words, the Condorcet Criterion is not inconsistent, but passing
> the Condorcet Criterion guarantees failing the Consistency Criterion.
> For a simple proof of this, see Markus Schulze's posting at
> http://www.mail-archive.com/election-methods-list@eskimo.com/msg06140.html

I see...  What you are saying is that when all precincts report the
same Condorcet Winner, then any Condorcet method will be consistent,
and report the same Condorcet Winner as all the precincts.  But for
any Condorcet method, it is possible to derive a set of ballots such
that all precincts report the same winner (with, of necessity, at
least one ballot's winner not a Condorcet Winner, however), yet report
a different winner for the election as a whole.

OK, I concede the point, but you know what?  I don't care.

First of all, consistency isn't an issue when the precincts report
different winners.  The criterion isn't a guide then.  I suspect that
most of the time when there fails to be a uniform Condorcet winner
across precincts, it'll be because different precincts report
different winners.  So it isn't an issue then.

Second of all, I consider the resolution methods used in Condorcet
methods when there is no Condorcet winner to be "tie-breakers".  There
is a group of candidates between whom the electorate cannot make a
clear decision -- so the process tries to use the information
available as best it can.  So when all 10 precincts (say) select
candidate A with precincts 1-9 having Condorcet Winners, and 10 having
A selected but not the Condorcet Winner, then I'd say an accurate way
to report the results is that "A has a clear victory in precincts 1-9,
but in precinct, the race is too close to call -- a statistical deal

I'm falling asleep, I'll answer the rest tomorrow...


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