[EM] To Blake, re: pushover examples
nkklrp at hotmail.com
Sun Apr 29 19:43:11 PDT 2001
>Proponents of other voting systems always say that pairwise-count
>methods are strategy-ridden. I'm going to show some examples here,
>show that they're right--when the method a Margins method.
My problem with your analysis is that you decide that truncation is
the chief enemy,
As I said, truncation & falsification are the 2 things that can
make a sincere CW lose in a pairwise-count method. And order-reversal
is the kind of falsification that's effective against a CW whose support
isn't reduced by indifference.
But I wrote about order-reversal too, not just truncation.
I do believe that truncation is much more likely, in public elections,
on a scale sufficient to change the result. I don't think order-reversal
will occur on that scale in public elections, with wv. If it did,
people would soon learn not to do it. So yes, I believe that truncation
is a more realistic concern in wv, though I & others will be making good
use of order-reversal in Margins. (But I didn't use it in this poll,
because it would be improper, since I have access to ballots in a
so you construct a method that on average punishes
people for using partial rankings (strategic or not).
No, I said that wv merely doen't let truncation steal an election,
as it can so easily do in Margins.
But if they
want their ballot to be fully counted, they can still randomly rank
the rest of their ballot.
Blake is referring to the fact that in a 0-info election, one can
gain some expectation by randomly ranking some equally-preferred
bottom candidates, something that could pay off only in a natural
circular tie. Blake, I asked you for examples of how that & your other
strategy objection can cause bad consequences. I notice that you
haven't posted any such examples. It couldn't be, could it, that that's
because you don't have any examples in which those wv strategy "problems"
cause serious consequences?
These wv arguments really help IRV in the long run. You play up the
strategy problems of Condorcet methods, offering wv as the only
I'm not going to lie for your cause. I don't "play-up" strategy
problems. They're real.
Maybe people will be so convinced of the strategy problems
that they are willing to accept anything offered as a solution, out of
Good, I hope they reject Margins and accept something that genuinely
gets rid of Plurality's problems.
Then, I come along and point out that wv doesn't really do any good
Thank you, but would you show some examples showing how wv produces
seriously bad results, results as bad as the Margins results that
wv gets rid of?
The result is that people might be left with the
impression that Condorcet is hopeless.
Condorcet is hopeless if the Margies define it.
Even if I didn't point out
wv's problems, IRV advocates would, if wv became more well known.
They already do point out problems real and not-so-real. I routinely
answer them when they point out alleged problems of wv. But when they're
pointing out Margins' stupid strategic mess, I'm afraid that there
isn't much that I could say in its defense.
For example, you claim that there are "easy situations" where
truncation is safe to use in margins. Clearly, in wv, the usurpers
could randomly rank the remaining candidates instead of truncating.
Yes, and I asked you for an example in which that would cause a
seriously bad result. Where's your example to show how bad a
result can be caused by that strategy?
So, really, we can only conclude that strategy is easy in wv too.
I don't know how many time it will be necessary to repeat this:
Gibbard & Satterthwaite showed that every method can have situations
in which someone could gain from strategy. That's possible in wv
too, because wv is a voting system. As I keep having to repeat, then it's
really about which strategy situation is worse. Which causes a serious
problem for voters. Which causes a lesser-of-2-evils problem? Blake,
show us an example that shows how bad a result can occur due to wv's
course, that isn't considering the truncation-for-sheer-spite
What isn't considering it. I'm considering it. That's one reason why
there can be truncation. Other reasons are strategic, and lazy, and
principled--I'd refuse to rank anyone unacceptable, just as I'd refuse
to rank an unacceptable voting system in a voing system poll.
It's ironic that truncation is made such an issue. It isn't really
ever good strategy to truncate
Truncation is common in rank-balloting. It's occurred in every rank
balloting I've participated in. Truncation isn't only done with
instrumental strategic intent. Strategic truncation will most likely
be only a small fraction of truncation. Truncation is common enough
to be able to change the outcome of a public election. To steal an
election counted by Margins.
But you're right about one thing: Truncation doesn't work in
wv as an offensive strategy against a sincere CW or against a member
of the sincere Smith set.
, or randomly rank, in either margins or
wv. If you're tempted to use partial rankings as a strategy, order
reversal is even better.
Are you sure that there aren't situations where truncation is safe
but order-reversal isn't? But sure, order-reversal is more likely to
get results than truncation is. When you say that order-reversal is
an even better offensive strategy in Margins, it isn't clear how
you consider that a Margins advantage.
Yes, in wv, if you want to do offensive strategy against a CW or
sincere Smith set member, it has to be order-reversal, because that's
all that can work. I emphasize truncation because it will happen
much, even though it won't work against a sincere CW or member of the
sincere Smith set in wv.
But I agree with you: I & others will be making much use of Margins'
easy order-reversal opportunities if Margins is enacted.
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