Ho-Hold it a Gosh-Darn Minute! They won't truncate.

[Mike Ossipoff]

Rob Lanphier writes:

[Mike says: This isn't a reply to Don; it's a reply to Rob.
When one of Don's far-out claims gets agreement or is taken
seriously, then I'll comment. Otherwise, I really do intend
to keep my promise about not replying to Don, in keeping with
Rob's suggestion, and it would be great if other people would
likewise ignore Don's perpetual repetition of refuted claims
to which Don hasn't answered the refutations]


My reply is a little farther down in the letter.

> 
> This is a good post.  I have some questions, though...
> 
> On Mon, 2 Dec 1996 donald at mich.com wrote:
> > Dear DEMOREP1, I am willing to accept your Instant Run-off example for
> > debate but I have some conditions.
> > 
> > Condition One: These five voters are experienced in three election methods
> > - Plurality - Instant Run-off - Condorcet.
> > 
> > Condition Two: Before the election the voters are told which method is
> > going to be used to crunch the results - and only that method can be used
> > on the returns of that election.
> > 
> > Condition Three: There is to be three elections on one ballot - Plurality -
> > Instant Run-off - Condorcet - as follows:
> > 
> >     Plurality       |        Instant Run-off     |        Condorcet
> >    vote for one     |           1   2   3        |          1   2   3
> >        A []         |        A []  []  []        |       A []  []  []
> >        B []         |        B []  []  []        |       B []  []  []
> >        M []         |        M []  []  []        |       M []  []  []
> > 
> > I say the results of these three elections will be as follows:
> > 
> >     Plurality       |        Instant Run-off     |        Condorcet
> >        2 A          |            2 AM            |           2 A
> >        2 B          |            2 BM            |           2 B
> >        1 M          |            1 MB            |           1 M
> > 
> > The Instant Run-off results are the same as your example.
> 
> This is a fair and most likely accurate assumption.

What?? This is one of the claims that Don has been recycling
& re-using over & over, quite oblivious to the fact that it's
been refuted each time.

What reason would the A & B voters have to not inlcude M
in their ranking? If anyone has an answer to that question
then I hope they'll post it. 

A & B voters have nothing to gain by not ranking M. And one
of them, they may or may not know which, has much to lose
by not ranking M. They'll rank M.

As I've said on each previous occasions when Don repeated that
same claim: Condorcet's method is "truncation-resistant":

A method is "truncation-resistant" if truncation can never
gain the election of an alternative over which a majority 
have ranked the Condorcet winner (which I'm going to start
calling the Universal winner--the alternative that would
beat each of the others in separate 2-alternative races; the
alternative which, when compared separately to each one of the
other, is preferred to it by more voters than vice-versa).

Why is Condorcet truncation-resistant? If a majority have ranked
M over A, then truncation by A voters can't change the fact that
A has a majority against it. And truncation by the A voters can't
change the fact that M doesn't have a majority against it. If
there were a majority who preferred some other alternative to M,
then M wouldn't be Condorcet winner.

Have I finally laid this old, old claim to rest??
 
> 

> > The results of the Condorcet election will be the same as the Plurality
> > election. The reason for this is because EXPERIENCED voters in a Condorcet
> > election will not make a second selection - because they know that the
> > second selections will be used to help some candidate other than the
> > candidate of their first choice.

Yes, the 2nd choice votes will help a 2nd choice beat a last choice.
But A & B have absolutely nothing to lose by listing a 2nd choice,
and nothing to gain by not doing so, and much to lose by not doing
so.

I repeat my repetition of Rob's suggestion that we not reply
to Don when Don is re-cycling a many-times refuted claim.

>
 
> Two questions:
> 
> 1.  Are the voters aware of semi-accurate polling data (or in a genuine 5
> person election, do they have a pretty good idea of who the others would 
> rank on top)?

It wouldn't matter. Either way, as I said, A & B voters have nothing
to gain by not lising a 2nd choice, nothing to lose by listing
a 2nd choice, and much to lose by not listing a 2nd choice.

> 
> 2.  What is the tie-breaker assumed to be in all cases (especially
> Condorcet)?  If we are to assume experienced voters here, then they would
> undoubtedly factor in the tie-breaker in an election so likely to produce
> a tie.

I don't think that, in a Condorcet vote, the tie-breaker would
influence people's voting, because no one could predict for
sure that there'd be a Condorcet tie. Of course if it were a
small election, & everyone knew exactly how others would vote,
the a Condorcet tie could be predicted if there were going to
be one--I admit that. That's a question that hadn't occurred to
me. If the tie-breaker were Plurality.ext or Stepwise-Plurality,
and I knew that the winner of the tie-breaker would be something
that I like less than Z, then I guess I'd do what it took to
make Z win instead. But I emphasize that that isn't a Condorcet
problem: Every method is equally likely to have ties in small
elections (except that Copeland is likely to have them in big
elections too). But if it's a tie between X & Z, does it really
matter if I use strategy to make X win, instead of letting Z
win the Plurality tie-breaker?


> 
> Rob
> 
> 
> 
> .-
> 


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