<div dir="ltr"><div><div><div>Sorry to bother you yet again about this comparison, but I just want to say one more thing about it:<br><br></div>It occurs to me that I was needlessly worried about a conflict, in MDDAsc, between protecting against chicken-dilemma defection by B's voters, vs protecting B from truncation & burial if s/he is CWs.<br><br></div>II realize that, in the standard chicken-dilemma example, C is majority-disqualified, and is the only majority-disqualified candidate.<br><br>In that 3-candidate example, if B were the larger of {A,B}, and were CWs, then, with the B voters not ranking or approving C, then, if the C voters buried B under A, they'd thereby elect A as the only non-disqualified candidate. (as several people have already pointed out).<br><br></div><div>So, in the chicken-dilemma situation, even if B were the CWs, s/he wouldn't need an approval from A, for deterrence against truncation or burial. The chicken-dilemma exists when people feel pretty sure that it exists. If it looks & feels like a chicken-dilemma situaton, i probably is. It's disconcertingly obvious. And, then, there's no need to worry "What if it might, instead, be a situation in which B needs approval from the A voters?" <br><br></div><div>So my concern about that was needless.<br><br></div><div>It's clear when it's a chicken-dilemma situation, and MDDAsc works fine in that situation. The voter has the option of dealing with the chicken-dilemma situation when it's clear that there is one, and also _fully, solidly, positively_ protecting, from truncation & burial, middle-ranked candidates who need that protection.<br><br></div><div>Michael Ossipoff<br><br></div><div><br><br></div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Nov 24, 2016 at 10:27 PM, Michael Ossipoff <span dir="ltr"><<a href="mailto:email9648742@gmail.com" target="_blank">email9648742@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div>Kevin suggested IC,MMPO, as a method that meets FBC, avoids chicken-dilemma, and has MMPO's (uncertain) kind of protection of a middle-ranked CWs.<br><br></div>MMPOsc achieves that too,and the symmetrical completion avoids the Hitler-with-2-votes bad-example. But the symmetrical completion that it needs spoils its truncation-proofness.<br><br></div>So an advantage of IC,MMPO over MMPOsc is truncation proofness, because the IC avoids MMPO's bad-example, and so the symmetrical completion isn't needed.<br><br>Forest's MDDAsc could be used with IC too. IC,MDDAsc would add a sort of Condorcet-Criterion compliance. I guess the symmetrical completion would still be needed, to keep Mono-Add-Plump,but, it doesn't do any harm to MDDA's solid, positive protection of a middle-ranked CWs to whom approval isn't denied..<br></div><br></div>So that's four related methods:<br><br></div>MDDAsc<br></div>MMPOsc<br></div>IC,MDDAsc<br></div>IC,MMPO<br><br></div>Some advantages among them:<br><br></div>MDDAsc: <br><br></div>Protection of a middle-ranked CWs is positive & solid, if approval isn't denied that candidate. <br><br></div><div>MMPOsc:<br></div><br></div>Chicken-dilemma deterrence is automatic. All middle-ranked candidates would receive some (uncertain) protection if they're CWs. But the protection of _any_ middle-ranked CWs is uncertain, and might or might not be there. <br><br></div><div>The necessary symmetrical completion spoils the truncation-proofness that MMPO would otherwise have..<br><br></div><div>Deterrence of burial and truncation depends on the would-be buriers knowing if the strength of pairwise oppositions favors them, or will result in penalty. It depends largely on whether the candidate under whom they bury the CWs has strong pairwise opposition other than by the CWs. Maybe that threat would depend on the voters of the defending wing, between the median and any possible burying-candidate, purposely leaving hir only weakly pairwise-opposed (other than by the CWs). If there are a number of candidates under whom the CWs could be buried, and who could receive strong pairwise opposition, then it might be necessary to give low opposition (other than by the CWs) to a number of them.<br><br></div><div>Anyway, the protection of a middle-ranked CWs is always uncertain.<br></div><br></div>IC,MDDAsc: <br><br></div>Compiance with Improved Condorcet Criterion is added to MDDAsc's properties.<br><br></div><div>IC,MMPO. <br><br>Same as above. Also, because symmetrical completion isn't needed, due to IC, this method has, as an advantage over MMPOsc, that it's truncation-proof.<br><br></div><div>------------------------------<wbr>-------------------<br><br></div><div>MDDAsc & IC,MDDAsc seem to win the comparison because the voter can give full, sold, positive protection to a candidate to whom s/he doesn't deny approval. Chicken dilemma will be relatively uncommon, and so approval won't usually be denied.<span class="HOEnZb"><font color="#888888"><br><br></font></span></div><span class="HOEnZb"><font color="#888888"><div>Michael Ossipoff<br></div><div><br></div><br><div><div><div><div><div><div><div><div><div><div><div><div><br><br></div></div></div></div></div></div></div></div></div></div></div></div></font></span></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Wed, Nov 23, 2016 at 8:09 AM, C.Benham <span dir="ltr"><<a href="mailto:cbenham@adam.com.au" target="_blank">cbenham@adam.com.au</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5">
<div bgcolor="#FFFFFF" text="#000000">
<div class="m_3462638492690337764m_-9221225578524578282moz-cite-prefix">On 11/23/2016 10:59 AM, Kevin Venzke
wrote:<br>
<br>
<blockquote type="cite"><span style="font-size:16px" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_61103">Hmm, with a movable
cutoff MDDA already violates Plurality with three candidates.
Do you think symmetric-completion of the bottom can save it?</span></blockquote>
<br>
Yes.<br>
<br>
Something Toby Pereira wrote (9 Nov. 2016) regarding "Irrelevant
Ballots" got me thinking. The criterion I defined just talks about
ballots <br>
that plump for nobody, but there can also be a problem with
ballots that only vote nobodies below, say, equal-top.<br>
<br>
Under MDDA with symmetric completion only at the bottom, adding
ballots like that can wash away "majority-defeat"<br>
disqualifications and make the result less Condorcet-consistent.<br>
<br>
This has led me to think of a modification to fix this problem
that looks to be too good to be true, but so far I can't see how.<br>
<br>
*Voters submit rankings with an explicit approval cutoff. (I
prefer default placement to be just below candidates ranked below
no-one).<br>
<br>
On the ballots that have been symmetrically completed at the
bottom, find the smallest set S of candidate/s that
majority-strength pairwise<br>
beat all the outside-S candidates.<br>
<br>
Disqualify the outside-S candidate/s and delete all the ballots
that make no distinction among the inside-S candidates.<br>
<br>
Repeat as many times as possible. If at the end of this process
more than one candidate hasn't been disqualified, elect the<br>
one of those by normal MDDA (SC).*<br>
<br>
I am fearful that this might fail FBC and/or mono-raise, but I
can't (yet) see how it does.<br>
<br>
45: A>B>>C<br>
10: A=B<br>
40: B<br>
05: C<br>
<br>
100 ballots. After symmetrically completing at the bottom we get
A>B 47.5 - 42.5, A>C 75-25, B>C 95-5.<br>
<br>
Normal MDDA(SC) disqualifies only C and then elects the most
approved candidate, B.<br>
<br>
My suggested version first disqualifies C and then deletes the 5
C and 10 A=B ballots and then disqualifies B leaving A (the
CW)<br>
as the winner.<br>
<br>
What do you think?<br>
<br>
Chris Benham<br>
<br>
<br>
On 11/23/2016 10:59 AM, Kevin Venzke wrote:<br>
</div>
<blockquote type="cite">
<div style="color:#000;background-color:#fff;font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:12px">
<div id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60274"><span><font size="3">Hi
Chris,</font></span></div>
<div class="m_3462638492690337764m_-9221225578524578282qtdSeparateBR" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60273"><br>
<br>
</div>
<div class="m_3462638492690337764m_-9221225578524578282yahoo_quoted" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60298" style="display:block">
<div id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60297">
<div id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60296">
<div dir="ltr" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60295"> <font id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60294" size="2" face="Arial">
<hr id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_62295" size="1"> <b id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_62869"><span style="font-weight:bold" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_62868">De :</span></b>
C.Benham <a class="m_3462638492690337764m_-9221225578524578282moz-txt-link-rfc2396E" href="mailto:cbenham@adam.com.au" target="_blank"><cbenham@adam.com.au></a><br>
<b><span style="font-weight:bold">À :</span></b>
Michael Ossipoff <a class="m_3462638492690337764m_-9221225578524578282moz-txt-link-rfc2396E" href="mailto:email9648742@gmail.com" target="_blank"><email9648742@gmail.com></a> <br>
<b id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_62872"><span style="font-weight:bold" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_62871">Cc :</span></b>
EM <a class="m_3462638492690337764m_-9221225578524578282moz-txt-link-rfc2396E" href="mailto:election-methods@lists.electorama.com" target="_blank"><election-methods@lists.electo<wbr>rama.com></a>;
Forest Simmons <a class="m_3462638492690337764m_-9221225578524578282moz-txt-link-rfc2396E" href="mailto:fsimmons@pcc.edu" target="_blank"><fsimmons@pcc.edu></a><br>
<b><span style="font-weight:bold">Envoyé le :</span></b>
Mardi 22 novembre 2016 10h51<span><br>
<b><span style="font-weight:bold">Objet :</span></b>
Re: [EM] Trying to have CD, protect strong top-set,
and protect middle candidates too<br>
</span></font> </div>
<div class="m_3462638492690337764m_-9221225578524578282y_msg_container" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60302"><br>
<div id="m_3462638492690337764m_-9221225578524578282yiv4410041191">
<div id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60301"><span>
<div class="m_3462638492690337764m_-9221225578524578282yiv4410041191moz-cite-prefix" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60300"><span style="font-size:16px" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60845">On
11/22/2016 9:25 AM, Michael Ossipoff wrote:</span><br clear="none">
<br id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60832" clear="none">
<span style="font-size:16px" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60843">>>With
</span><font id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60876" size="3">MDDTR, if your plump for X makes hir
lose, it's because you added a ballot. It has
nothing whatsoever to do with the fact that the
new ballot plumped for X.<br>
>>Your ballot made X lose in spite of the
fact that it was a plump for X, not because it
was a plump for X.<br>
>>But in IRV, when you make X lose by
raising hir from last place to 1st place, that
raising of X was the only thing that you did,
and it is the reason why X lost.</font></div>
<div class="m_3462638492690337764m_-9221225578524578282yiv4410041191moz-cite-prefix" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60300"> <font id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_61028" size="3">><br clear="none">
<span id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60840">>That
"distinction" is meaningless and completely
useless. The idea that adding a ballot is
"something you did" that rates a mention is
ridiculous.</span></font></div>
<div class="m_3462638492690337764m_-9221225578524578282yiv4410041191moz-cite-prefix" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60300"><font size="3"><br>
</font></div>
</span><div class="m_3462638492690337764m_-9221225578524578282yiv4410041191moz-cite-prefix" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60300"><font id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60874" size="3">I'm
not sure about this specific example but I think
this kind of distinction could be a useful
defense. For IRV I might argue that a mono-raise
failure happens not just from raising the winner
but also <i id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_62253">lowering</i> some
other, incidental candidate. The reason
mono-raise failures are offensive is that
supposedly the voter has done nothing but aid
the preexisting winner. But at least in IRV i</font><span style="font-size:16px" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60873">t is not
so clear as that.<span><br clear="none">
<br clear="none">
<blockquote type="cite" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60311"><span class="m_3462638492690337764m_-9221225578524578282yiv4410041191"> </span></blockquote>
>Regarding MDDA, symmetrically completing
the ballots only at the bottom and having a
moveable approval cutoff fixes its failures of
Mono-add-Plump<br clear="none">
>and Plurality and Irrelevant Ballots
Independence and in my opinion makes it a
good/acceptable method.</span></span></div>
<div class="m_3462638492690337764m_-9221225578524578282yiv4410041191moz-cite-prefix" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60300"><span style="font-size:16px"><br>
</span></div>
<div class="m_3462638492690337764m_-9221225578524578282yiv4410041191moz-cite-prefix" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60300" dir="ltr"><span style="font-size:16px" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_61103">Hmm, with
a movable cutoff MDDA already violates Plurality
with three candidates. Do you think
symmetric-completion of the bottom can save it?</span></div>
<div class="m_3462638492690337764m_-9221225578524578282yiv4410041191moz-cite-prefix" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60300" dir="ltr"><span style="font-size:16px"><br>
</span></div>
<div class="m_3462638492690337764m_-9221225578524578282yiv4410041191moz-cite-prefix" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60300" dir="ltr"><span style="font-size:16px" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_62843">For
whatever interest it may be, I calculated the
"DNA" for the method you describe and got the
exact same 343-digit code as for ICA(explicit).
That's the first time I've hit a method I
already had...<br clear="none">
<br clear="none">
Chris Benham<br clear="none">
</span></div>
<div class="m_3462638492690337764m_-9221225578524578282yiv4410041191moz-cite-prefix" id="m_3462638492690337764m_-9221225578524578282yui_3_16_0_1_1479854184911_60300"><span style="font-size:16px"><br>
</span></div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
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</blockquote>
<p><br>
</p>
</div>
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