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On 9/8/2016 5:01 AM, Jameson Quinn wrote:<br>
<br>
<blockquote type="cite">I am completely baffled by the idea that
IBIFA is less complicated than U/P.</blockquote>
<br>
C: I never said that it was. I just said that U/P is "quite
complicated", meaning that it is a lot more complicated than
Approval (and more complicated than MTA). Its extra complexity
over<br>
those methods doesn't seem to buy much.<br>
<br>
if you include in U/P 's explanation all the palaver about the
default ratings it becomes quite long and complex. 3-slot IBIFA
can be defined fairly succinctly, but I'm<br>
not sure how well the "man in the street" would understand it.<br>
<br>
<blockquote type="cite">I also don't agree that .. U/P "nearly
always simply elects the Approval winner".</blockquote>
<br>
C: Again, I'd be interested in seeing a plausible example of when
it doesn't.<br>
<br>
<blockquote type="cite">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. </blockquote>
<br>
C: Why not?<br>
<br>
<blockquote type="cite">Dominant in top-ratings: taking this as a
strong argument for who the correct winner is, is inherently
subject to clone effects</blockquote>
<br>
C: I never used the phrase "dominant in top-ratings". These are
supposed to be ratings (instead of simply rankings). In that case
clones are technically supposed to be rated the same.<br>
<br>
At one point I said that C would be "positionally dominant" if all
C's supporters truncated, meaning C would have both the highest
Top Rating score and the highest Approval score.<br>
<br>
<blockquote type="cite"> 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.</blockquote>
<br>
C: No, you have to be able to justify the result on the assumption
that all the votes are sincere, or at least are all equally likely
to be sincere. Otherwise you'd be able to argue<br>
that in this or that scenario the most ridiculous method "gave
the best result".<br>
<br>
Chris Benham<br>
<br>
</div>
<blockquote
cite="mid:CAO82iZz=bX74M5sc4TbnubGi+=-_S9Q_ZEq2VzUSBLi8dr+Y5Q@mail.gmail.com"
type="cite">
<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 moz-do-not-send="true"
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
moz-do-not-send="true"
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>
</div>
</div>
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