more on fairness & votes-against

Steve Eppley seppley at alumni.caltech.edu
Sat Apr 20 16:55:28 PDT 1996


Mike O wrote [about Elimination of Worst Pairwise-Defeated Candidate]:
>In the Dole, Clinton, Nader examples we've discussed, Clinton in the
>order-reversal examples, would immediately be eliminated, leaving
>only Dole & Nader.  Dole beats Nader, so Dole wins, as I understand
>that method. So that method would reward the order-reversal of the
>Dole voters. I haven't checked Condorcet-Elimination's results in
>enough truncation situations to know if it fails there too, but the
>fact that it doesn't do as well as the Condorcet's method that I've
>already proposed when it comes to order-reversal is reason enough
>for me to prefer the method that I've been proposing as Condorcet's
>method.
>
>One other thing: You mentioned a defensive strategy, against
>order-reversal, that could be used by the Clinton voters: If they
>expect order-reversal by the Dole voters, then the Clinton voters
>could insincerely rank Nader over Dole. I already pointed out that
>insincere defensive strategy is what we want to get away from the
>need for, and that, with methods other than Condorcet's method,
>such strategy is needed not only for order-reversal, but also for
>the very common practice of truncation. 
>
>But what I didn't add is that if the Clinton voters used that
>general Pairwise defensive strategy to protect against order-reversal
>&/or truncation by the Dole voters, then they'd be setting themselves
>up for order-reversal &/or truncation by the Nader voters. If the
>voters who believe their favorite to be middle Condorcet winner
>don't know from which side the offensive strategy (or innocently-
>intended truncation) will occur, then they don't know how to vote.
>A defensive strategic dilemma, just what we want to avoid.
[snip]

But isn't the order reversal by the Dole voters one of those
scenarios where such a tactic on such a massive scale couldn't be
kept secret?  If so, it may be reasonable to accept the existence of
this tactic if the Condorcet-Elimination method's results are
"better" overall, like in the case where the {Dole>Nader>Clinton}
votes are sincere, not tactical.  If one believes that a Dole
victory there is more appropriate than a Nader victory (i.e., if one
believes {Clinton>Dole=Nader} votes shouldn't hurt Dole more than
Nader), then isn't it sensible to rely on the Clinton voters to
punish the Dole voters' massive nonsecret dishonesty?  As long as the
Clinton voters don't have to reverse their Clinton>Nader and
Clinton>Dole preferences to punish, this counter-tactic won't be a
dilemma for them.

If Condorcet-Elimination results can be seriously upset by
truncation, that would be a more serious problem. 

--Steve



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