<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">2016-11-12 10:45 GMT-05:00 C.Benham <span dir="ltr"><<a href="mailto:cbenham@adam.com.au" target="_blank">cbenham@adam.com.au</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div class="m_-680782387900465520moz-cite-prefix">On 11/12/2016 7:53 AM, Jameson Quinn
wrote:<br>
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<div class="gmail_quote">2016-11-11 12:50 GMT-05:00 C.Benham <span dir="ltr"><<a href="mailto:cbenham@adam.com.au" target="_blank">cbenham@adam.com.au</a>></span>:<br>
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<div class="m_-680782387900465520m_-8048598155404746332gmail-m_-2730114550739300614moz-cite-prefix"><span class="m_-680782387900465520m_-8048598155404746332gmail-">On 11/11/2016
10:14 PM, Jameson Quinn wrote:<br>
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<blockquote type="cite"> I think that simple PAR is
close enough to FBC compliance to be an acceptable
proposal.</blockquote>
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</span> I'm afraid I can't see any value in "close
enough" to FBC compliance. The point of FBC is to
give an absolute guarantee to (possibly uninformed<br>
and not strategically savvy) greater-evil fearing
voters.</div>
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<div>Yes. The guarantee you can give is "as long as the
world is somewhere in this restricted domain — that is,
essentially, as long as there are no Condorcet cycles and
each voter naturally rejects at least one of the 3
frontrunners — this method meets FBC". This is much
broader than any guarantee you could give for a typical
non-FBC method. For instance, with IRV, the best you could
say would be "as long as your favorite is eliminated early
or wins overall, you don't have to betray them", which
unlike PAR's guarantee is not something which could ever
be generally true about all real elections for all
factions.<br>
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C: I have in mind voters who are inclined to Compromise, and so
it's <i> absolute guarantee</i> or it's nothing. Smith//Approval
also has a much lower Compromise incentive<br>
than does IRV (which in turn has a much much lower Compromise
incentive then FPP).<span class=""><br>
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<blockquote type="cite">It elects the "correct"
winner in a chicken dilemma scenario,
naive/honest/strategyless ballots, without a
"slippery slope" (though of course, this is no
longer a strong Nash equilibrium). </blockquote>
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</span> How do you have a "chicken dilemma scenario"
with "naive/honest/strategyless ballots" ?<br>
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35: C >> A=B<br>
33: A>B >> C<br>
32: B >> A=C (sincere is B>A >> C)<br>
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In this CD scenario your method elects B in violation
of the CD criterion.<br>
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<div>You're suggesting that the sincere preferences are <br>
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35: C >> A=B<br>
33: A>B >> C<br>
32: B>A >> C<br>
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C: I'm not "suggesting". I'm stating.<span class=""><br>
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<div>If you are 1 of the B>A>>C voters considering
whether to strategically vote B>>A=C, you have no
strong motivation to do so, because your vote alone is not
enough to shift the winner to B. This is what I mean by
"no slippery slope".<br>
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C: One "vote alone" is very rarely enough to do anything, so I
suppose no-one has a "strong motivation" to vote.</div></blockquote><div><br></div><div>In Smith//approval, one vote alone would shift the above honest election; so the fact that it does not in PAR is indeed notable.</div><div><br></div><div>In particular: in PAR, there is no way for the B voters to strategize such that they win the above election, while still ensuring that C does not win no matter what the A voters do. This "safe" strategizing is grease on the slippery slope.</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000"><span class=""><br>
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<div>I believe that in the election you gave, there is no
way to tell what the sincere preferences are. <br>
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C: From just the information on the ballots, of course not (like any
election).<span class=""><br>
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Perhaps the B voters are strategically truncating A;
perhaps the C voters are strategically truncating B. So
the "correct winner" could be either A or B, but is almost
certainly not C. <br>
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C: By "correct winner" I assume you mean the sincere CW. But there
is reason to assume there is one. And if the B voters are actively
Burying C, it could be C.<span class=""><br>
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<div>The "CD criterion" requires the system to elect C,
merely to punish the B voters; I think that's perverse,
because, among other things, it means that a system does
badly with center squeeze, allowing the C faction to
strategize and win.<br>
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C: No, it merely says "not B". But CD + Plurality say that it must
be C.<span class=""><br>
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Since you are apparently now content to do without
FBC compliance and you imply that electing the CW is
a good thing,<br>
why don't you advocate a method that meets the
Condorcet criterion?<br>
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What is wrong with Smith//Approval? Or Forest's
nearly equivalent Max Covered Approval? <br>
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<div>Largely, it's because I think that Condorcet systems
are strategically counterintuitive, and hard to present
results in. I think that will lead to more strategy than a
system like PAR. That's because PAR can make guarantees
that Condorcet systems can't.<br>
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C: Such as? What exactly does "strategically counter-intuitive"
mean? An example?</div></blockquote><div><br></div><div>What I mean is that if you take a non-election-theorist, present an election scenario to them, explain who won and why, and ask how they would strategize in the place of voter X, they are more likely to suggest counterproductive strategies, and less likely to see any strategies that actually might work, in Condorcet than in Bucklin-like systems.</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000"><span class=""><br>
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<div>In a system like MJ or Score, you can give a number to
each candidate, based on their own ratings alone, and the
higher number wins. That is an easy way to get
monotonicity, FBC, and IIA.</div>
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<div>In Condorcet, no candidate has any number except in
relation to all other candidates. That's good for passing
the Condorcet criterion (obviously) but it breaks FBC and
IIA.<br>
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C: Your method and MJ fail IIA.</div></blockquote><div><br></div><div>MJ passes IIA. PAR fails it, as you say, but passes LIIA. </div></div><br></div></div>