<div dir="ltr">Once again, I'm going to stand behind my view that U/P is a better practical reform proposal than IBIFA, and that there are cases where U/P gets the right answer and IBIFA doesn't. But once again, I'm going to preface it by saying I think IBIFA is a great method overall.<div><br></div><div>So. Remaining debates.</div><div><br></div><div>Condorcet versus Majority Condorcet: I do not believe in the concept of "irrelevant ballots", or that we should "simplify" a scenario by removing a balanced set of ballots. </div><div><br></div><div>Dominant in top-ratings: taking this as a strong argument for who the correct winner is, is inherently subject to clone effects. My "unserious" example was a (serious) attempt to show this.</div><div><br></div><div>"<span style="font-size:12.8px">It seems that you want a quite complicated method with a nearly as strong as possible truncation incentive and that nearly always</span></div><span style="font-size:12.8px">simply elects the Approval winner (while somehow "tending to respect" majority Condorcet without actually meeting the Majority</span><br style="font-size:12.8px"><span style="font-size:12.8px">Condorcet criterion)."</span><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">I am completely baffled by the idea that IBIFA is less complicated than U/P. If you want to, we can each post a 3-minute video where we explain our method to a random "person on the street" and then ask the person to explain it back to us. I'll bet that this would show U/P as far simpler to understand. If you agree, I'll let you set any reasonable procedure for each choosing our subject/explainee.</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">I also don't agree that the U/P has a "nearly as strong as possible truncation incentive" or "nearly always simply elects the approval winner".<br></span><div>On the first point: I think that in a chicken dilemma situation, U/P would lead to less truncation than many other methods, including things like MCA or MJ, because in U/P, chicken truncation is only helpful precisely insofar as it's risky. On the second: I think that there is a not-insignificant subset of voters who strongly want to cast a ballot that's expressive enough to distinguish their favorite from their preferred frontrunner. In approval, such people would bullet vote; in U/P, they could still rate the compromise frontrunner as acceptable. This could easily lead to different (and better) outcomes.</div></div></div><div class="gmail_extra"><br><div class="gmail_quote">2016-09-07 15:01 GMT-04:00 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">
<div bgcolor="#FFFFFF" text="#000000">
<div><span class="">On 9/7/2016 10:15 PM, Jameson Quinn
wrote:<br>
<br>
<blockquote type="cite">C: C is the clearly voted Condorcet winner
<div><br>
</div>
<div>But not the majority Condorcet winner. I regard majority
Condorcet as something any good voting system should tend to
respect, but non-majority Condorcet as only a weak signal.</div>
<div> <br>
</div>
</blockquote>
<br></span>
C: The Majority Condorcet winner is always the Condorcet winner.
It is ridiculous to suggest that failing to elect a Condorcet
winner is a step in the<br>
direction of "tending to respect the majority Condorcet winner".<br>
<br>
The "Majority Condorcet" concept is vulnerable to Irrelevant
Ballots, and to put it forward as some especially desirable
criterion is nonsensical. <br>
<br>
In our example, would removing 3 plumping ballots from each of the
candidates really turn C into a stronger candidate? Because the
effect would <br>
be to change C from a mere Condorcet winner (who you say should
lose to the approval winner) into a fabulous Majority Condorcet
winner (who you<br>
say the method should "tend" to respect).<br>
<br>
(The only point of the criterion is that some methods happen to be
able to meet it, but not the normal Condorcet criterion.)<span class=""><br>
<br>
<div>20: A>B </div>
<div>25: B>A</div>
</span><div>20: C>B </div>
<div>26: C<br>
<br>
91 ballots. Majority threshold = 46. <br>
<br>
C > B 46-45, C > A 46-45. <br>
<br>
Or of course the question can be posed the other way: does
giving each candidate 3 extra plumping ballots really make C a
weaker candidate?<span class=""><br>
<br>
<blockquote type="cite">
<div>Whoops... I'm sorry. Those were the averages over a large
number of polls, but then a week before the election, A had
a heart attack. The actual scores, with 3 ballots still to
count from A's former stronghold precinct, are:</div>
<div><br>
</div>
<div>48: B</div>
<div>49: C</div>
<div><br>
</div>
<div>I guess C wasn't so dominant in top-ratings after all.
Once we count those last three ballots, we'll have a clear
winner here, and there's every chance it could be B.</div>
<div> </div>
</blockquote>
<br>
</span></div>
C:I take it this is Jameson not being serious (and perhaps trying
to shift goal-posts).<br>
<br>
One of IBIFA's obvious advantages over "U/P" and MJ and the
other Bucklin methods is that it has a <br>
much weaker truncation incentive. In the example (with 100
ballots) U/P penalised the 20 C>B voters<br>
for not truncating. Had they done so C would have won.
(Unsurprising, since that would have made C positionally<br>
dominant as well the Condorcet winner).<br>
<br>
It seems that you want a quite complicated method with a nearly as
strong as possible truncation incentive and that nearly always<br>
simply elects the Approval winner (while somehow "tending to
respect" majority Condorcet without actually meeting the Majority<br>
Condorcet criterion).<br>
<br>
BTW, I'd be mildly interested in seeing one or two of your
realistic examples where U/P doesn't elect the Approval winner.<br>
<br>
Given from what I can make of your method goals, why don't you
simply propose Majority Condorcet//Approval ?<br>
<br>
Chris Benham<br>
<br>
</div>
<blockquote type="cite"><div><div class="h5">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">2016-09-07 8:17 GMT-04:00 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">
<div bgcolor="#FFFFFF" text="#000000">
<div><span><br>
<div>3: A</div>
<div>20: A>B</div>
<div>25: B>A</div>
<div>3: B</div>
<div>20: C>B</div>
</span>
<div>29: C<br>
<br>
C > B 49-48, C > A 49-48, B > A 48-23.<br>
<br>
Top Ratings scores: C 49, B 28, A 23<br>
<br>
Approval scores: B 68, C 49, A 48.<span><br>
<br>
On 9/7/2016 7:09 AM, Jameson Quinn wrote:<br>
<blockquote type="cite">IBIFA elects C. U/P elects
B. It's clear to me that B is better. The 3
A-only voters are likely attempting a chicken
strategy.</blockquote>
<br>
</span></div>
C: C is the clearly voted Condorcet winner</div>
</div>
</blockquote>
<div><br>
</div>
<div>But not the majority Condorcet winner. I regard
majority Condorcet as something any good voting system
should tend to respect, but non-majority Condorcet as only
a weak signal.</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div> and by far the most top-rated candidate.</div>
</div>
</blockquote>
<div><br>
</div>
<div>Whoops... I'm sorry. Those were the averages over a
large number of polls, but then a week before the
election, A had a heart attack. The actual scores, with 3
ballots still to count from A's former stronghold
precinct, are:</div>
<div><br>
</div>
<div>48: B</div>
<div>49: C</div>
<div><br>
</div>
<div>I guess C wasn't so dominant in top-ratings after all.
Once we count those last three ballots, we'll have a clear
winner here, and there's every chance it could be B.</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div> The suggestion that "B is better" because of<br>
some guess that 3 truncators are "likely" attempting
some strategy is absurd.<br>
</div>
</div>
</blockquote>
<div><br>
</div>
<div>No, B is better because B has majority approval where C
is rejected by a majority. The argument about likely
truncation is merely how IBIFA went wrong, not how U/P got
it right.</div>
<div> </div>
<div>...Again, I don't regard this as a knockdown argument
against IBIFA. It's only one scenario; a roughly plausible
one, but not particularly likely. I think we should
probably drop this. But I do think it demonstrates pretty
conclusively that IBIFA at least isn't strictly dominant.
After all, as long as we're making up arbitrary scenarios,
we can arbitrarily assume that the 3 A voters are in fact
attempting strategy. Punishing strategy might not be the
worst thing in the world, but rather than punishing 48
voters for the strategy of 3, it would be better to ignore
the 3.</div>
<div><br>
</div>
<div>I'll write a broader response in a minute.</div>
</div>
</div>
</div>
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