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

Blake Cretney bcretney at postmark.net
Sun Sep 30 14:36:13 PDT 2001

On Wed, 26 Sep 2001 15:51:37 -0700 (PDT)
Forest Simmons <fsimmons at pcc.edu> wrote:
> The only winner that all Condorcet methods agree on is the CW
> beats-all winner.
> So if A wins in all of the precincts, but B wins the election, then
> all Condorcet methods would agree that A won in all of the precincts
> that B won the election.
> So in some appropriate topology, Condorcet Methods are on the
boundary of
> the set of methods that fail the Consistency Criterion, while IRV is
> interior to that set.
> In my opinion this line of reasoning is a better apologetic for
> Condorcet's relationship to the Consistency Criterion than the
> that tries to discredit the Consistency Criterion itself. 
> In other words, saying we almost reached the grapes is better than
> them sour.

I would agree that the consistency criterion is desirable to the
extent that it can be used as a criticism of methods that fail it. 
The consistency criterion is intuitive.  But once you think about it,
it doesn't actually make much sense.  So, I think it is much better to
attack the consistency criterion directly.

On the other hand, I can envision the following scenario.  Candidate X
says, I won decisively in every precinct, but lost over-all, how come?
 I retort, what do you mean, in this precinct, more people voted for
candidate Y over you than vice versa.  How can you say that you won
decisively in that precinct?

This retort will always work for any Condorcet completion method, so
they can be defended against someone who claims decisive victories.

> See my Greek Tragedy example in the archives at ...

All methods will have some results that are counter-intuitive, at
least to some people.  You can always construct an argument by
claiming that if the public sees such and such a result, they will
revolt, causing chaos, horror, and a bloody purge of election method
theorists.  The reality is that the current electoral process gives
frequent counter-intuitive results, and there isn't the slightest hint
of revolution (at least not from that).

Blake Cretney

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