David L Wetzell wrote:
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From: robert bristow-johnson <[email protected]
<mailto:[email protected]>>
To: [email protected]
<mailto:[email protected]>
Date: Thu, 24 Nov 2011 15:50:02 -0500
Subject: Re: [EM] More non-altruistic attacks on IRV usage.
On 11/24/11 2:20 PM, David L Wetzell wrote:
[...]
If you're going to undercut their marketing strategy then
ethically the burden of proof is on you wrt providing a
clear-cut alternative to IRV3.
Condorcet.
b.s.
In a world full of low-info voters and fuzzy-choices among political
candidates, rankings don't have the weight that rational choice
theorists purport for them.
Interestingly, Condorcet seems to deal with noise and fuzzy choices
better than does IRV. See http://bolson.org/voting/essay.html in general
and the graph about behavior under noise in particular. Brian Olson even
remarked that he was surprised by the resilience of Condorcet methods
against noise, though I have my own idea about why that is.
Of course, if you think those graphs are too synthetic, you probably
won't be convinced by them. If you do, I'd ask if there's any way we
could perform simulations that would convince. For instance, could we
introduce noise to real world voting data and see how the methods behave
as the noise is increased? Would that be good?
(My idea of why Condorcet methods resist noise is, to be short,
something like this: Kemeny can be considered a maximum-likelihood
estimator under a certain noise model. Other advanced Condorcet methods,
like Ranked Pairs, can be considered so, as well, under more complex
noise models. However, I am not aware of such a maximum-likelihood
estimation for non-Condorcet methods, so if Condorcet methods are
particular in this respect, then they would uniquely resist noise to the
extent the MLE noise model is similar to real world ballot noise or
voter uncertainty.)
which Condorcet method i am not so particular about, but simplicity
is good. Schulze may be the best from a functional POV (resistance
to strategy) but, while i have a lot of respect for Markus, the
Schulze method appears complicated and will be a hard sell. i also
do not think that cycles will be common in governmental elections
and am convinced that when a cycle rarely occurs, it will never
involve more than 3 candidates in the Smith set. given a bunch of
Condorcet-compliant methods that all pick the same winner in the
3-candidate Smith set, the simplest method should be the one
marketed to the public and to legislators.
What works best for wines among wine connoisseurs will not work best for
politicians among hacks.
Well, for wine connoisseurs, you'd just use Range :-)
Many of the Condorcet properties are, I think, declared-strategy
properties. Majority rule enforces, under honesty, what you can get in
Range with strategy. The Condorcet criterion ensures you get, under
honesty, what you would get in a Nash equilibrium under MJ or Range. And
so on. If you're among honest men who know their intensity of
preference, just use Range - you probably don't need the
declared-strategy properties anyway.
(Although I suppose the case isn't *that* clear cut. Condorcet's jury
theorem etc.)
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