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<p>Toby,<br>
<br>
<blockquote type="cite">Also a run-off between the most two
approved candidates still has STAR's clone problem.</blockquote>
<br>
Some years ago I suggested that 2-round Top-Two Runoff could be
improved by using approval ballots in the first round<br>
and then having a runoff between the most approved candidate (the
AW) and the candidate with the most approval opposition<br>
to the AW (i.e. is most approved on ballots that don't approve the
AW).<br>
<br>
<blockquote type="cite">If the most approved candidate is cloned,
the run-off becomes irrelevant.
<div dir="ltr" data-setdir="false"><br>
</div>
</blockquote>
Spoken like someone who lives in parliamentist country. "Clones"
aren't necessarily identical. There could be slight political
differences<br>
or one may be less corrupt, or one could just have a much better
haircut.<br>
<br>
Parties being having incentive to each field two candidates (even
if they are "clones") is maybe not too bad. But STAR uses score
ballots<br>
so there is a danger that there being two candidates from the same
party might cause voters to not give both of them max score enough<br>
to stop both of them from making the final.<br>
<br>
<blockquote type="cite">However, I just don't think that STAR's
failure here can reasonably be called a monotonicity failure.</blockquote>
</p>
<p>I think it is very much like one and it's claiming of bragging
rights on that point over IRV is unfair and misleading.<br>
<br>
Chris<br>
<br>
<br>
<br>
<br>
</p>
<div class="moz-cite-prefix">On 20/08/2023 5:55 am, Toby Pereira
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:610190666.2188808.1692476710826@mail.yahoo.com">
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<div dir="ltr" data-setdir="false">Also a run-off between the
most two approved candidates still has STAR's clone problem.
If the most approved candidate is cloned, the run-off becomes
irrelevant.</div>
<div dir="ltr" data-setdir="false"><br>
</div>
<div dir="ltr" data-setdir="false">Toby</div>
<div><br>
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<div id="ydp88c83081yahoo_quoted_2635776054"
class="ydp88c83081yahoo_quoted">
<div style="font-family:'Helvetica Neue', Helvetica, Arial,
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<div> On Saturday, 19 August 2023 at 17:43:12 BST, Toby
Pereira <a class="moz-txt-link-rfc2396E" href="mailto:tdp201b@yahoo.co.uk"><tdp201b@yahoo.co.uk></a> wrote: </div>
<div><br>
</div>
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<div dir="ltr">Chris</div>
<div dir="ltr"><br clear="none">
</div>
<div dir="ltr">It's not that I disagree with your
views of STAR's behaviour as a method. And there are
changes that could be made that would improve STAR,
as you say. However, I just don't think that STAR's
failure here can reasonably be called a monotonicity
failure.</div>
<div dir="ltr"><br clear="none">
</div>
<div dir="ltr">Toby</div>
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class="ydp88c83081yiv7777493248yqt5714507941">
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id="ydp88c83081yiv7777493248ydp8a4fb1aayahoo_quoted_3344434024"
class="ydp88c83081yiv7777493248ydp8a4fb1aayahoo_quoted">
<div style="font-family:'Helvetica Neue', Helvetica,
Arial, sans-serif;font-size:13px;color:#26282a;">
<div> On Saturday, 19 August 2023 at 04:10:32 BST,
C.Benham <a class="moz-txt-link-rfc2396E" href="mailto:cbenham@adam.com.au"><cbenham@adam.com.au></a> wrote: </div>
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id="ydp88c83081yiv7777493248ydp8a4fb1aayiv4453078911">
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<p>Toby,<br clear="none">
<br clear="none">
</p>
<blockquote type="cite">I wouldn't count
this as a monotonicity failure because it
involves decreasing Y's score as well as
increasing X's.</blockquote>
<br clear="none">
<br clear="none">
This is like a sophist's technical
loophole. Why do we particularly care about
"monotonicity failure"? To avoid some
hypothetical mild embarrassment? <br
clear="none">
For the sake of marketing bragging rights? <br
clear="none">
<br clear="none">
Or because it is related to Push-over
strategy incentive/vulnerability? STAR is
much worse in that respect than IRV because
there the strategists are entirely<br
clear="none">
relying on other voters to both get their
favourite into the final two and to there
win the pairwise contest, so if too many of
X's supporters try the strategy it<br
clear="none">
could backfire. <br clear="none">
<br clear="none">
Whereas with STAR the strategists could be a
bit cautious and give the weak candidate
they are trying to promote into the final a
score of max. minus one<br clear="none">
while also giving their favourite X max.
points.<br clear="none">
<br clear="none">
That way all of X's supporters could use the
strategy and it could still succeed. <br
clear="none">
<br clear="none">
The 0-5 score ballot is too restrictive
(certainly for STAR) Say, as I earlier
advocated, the voters rank however many
candidates they want to and give an approval
cutoff wherever<br clear="none">
they want, and we elect the pairwise winner
between the two most approved candidates.<br
clear="none">
<br clear="none">
That would be very similar to STAR (0-5
score ballots) but wouldn't it be better?
And also a method that fails mono-raise and
Condorcet and many other criteria <br
clear="none">
and is obviously terrible?<br clear="none">
<br clear="none">
Chris<br clear="none">
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<div
class="ydp88c83081yiv7777493248ydp8a4fb1aayiv4453078911moz-cite-prefix">On
17/08/2023 9:47 pm, Toby Pereira wrote:<br
clear="none">
</div>
<blockquote type="cite"> </blockquote>
</div>
</div>
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id="ydp88c83081yiv7777493248ydp8a4fb1aayiv4453078911yqt17188"
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<div dir="ltr">I wouldn't count this as
a monotonicity failure because it
involves decreasing Y's score as well
as increasing X's. Mono-raise may have
been defined specifically for ordinal
ballots where raising a candidate
inevitably pushes others down. Whereas
with a rated ballot, I think one would
be more likely to define monotonicity
criteria in terms of increasing a
candidate's score while leaving all
others the same.</div>
<div dir="ltr"><br clear="none">
</div>
<div dir="ltr">Toby</div>
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id="ydp88c83081yiv7777493248ydp8a4fb1aayiv4453078911ydpfb885ae5yahoo_quoted_2472273349"
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<div style="font-family:'Helvetica
Neue', Helvetica, Arial,
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<div> On Thursday, 17 August 2023 at
05:43:00 BST, C.Benham <a
shape="rect"
href="mailto:cbenham@adam.com.au"
class="ydp88c83081yiv7777493248ydp8a4fb1aayiv4453078911moz-txt-link-rfc2396E"
rel="nofollow" target="_blank"
moz-do-not-send="true"><cbenham@adam.com.au></a>
wrote: </div>
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<p>Toby Pereira wrote: </p>
<blockquote type="cite">I'm not
a fan of STAR, but I am still
interested in seeing how it
stands up to scrutiny given
that it has a following.
(Actually I'm not aware of how
STAR fails monotonicity. I was
under the impression that it
passed.)
<div dir="ltr"><br
clear="none">
</div>
</blockquote>
<p>Toby,<br clear="none">
<br clear="none">
To give you a bit of a preview
before I get around to cooking
up all the examples, nothing
with such obvious Push-over
incentive can meet mono-raise
(aka "monotonicty")<br
clear="none">
<br clear="none">
Suppose X beats Y in the
final. Now suppose on some
ballots with Y above X, we
raise X so it is now above Y.
That could reduce Y's score
enough for it to be replaced
in the final<br clear="none">
by Z, a candidate that
pairwise beats X.<br
clear="none">
<br clear="none">
Voters who are mainly
concerned to have their
favourite X win and are fairly
certain that X will reach the
final will have a strong
incentive to give X max points
(5) and then also<br
clear="none">
give a 4 (or even a 5) to all
those candidates that they
think X can beat pairwise.<br
clear="none">
</p>
<p>If enough voters use that
strategy and it fails, both
the finalists could be
candidates with little sincere
support.<br clear="none">
<br clear="none">
Chris Benham<br clear="none">
<br clear="none">
</p>
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<div
class="ydp88c83081yiv7777493248ydp8a4fb1aayiv4453078911ydpfb885ae5yiv4142299930moz-cite-prefix">O</div>
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