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<div class="moz-cite-prefix">On 11/4/2016 4:38 AM, Michael Ossipoff
wrote:<br>
<br>
<blockquote type="cite">You've mentioned that pushover-incentive
spoils FBC. But I don't know of a way that failure could happen
with this method.</blockquote>
<br>
Yes, my earlier generalisation was mistaken. This method both
meets FBC and is vulnerable to Push-over.<br>
<br>
Normally Push-over involves promoting some weak candidate into a
(virtual) runoff, and not just switching off an unusual
"conditional approval"<br>
mechanism.<br>
<br>
Chris Benham<br>
<br>
</div>
<blockquote
cite="mid:CAOKDY5C5xY+GdTAUWz4A5qj-WObAwCOCm+i71bB+DU_tVG8X4Q@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>You've mentioned that pushover-incentive spoils FBC. But I
don't know of a way that failure could happen with this
method.<br>
<br>
</div>
<div>If I top-rate Compromise & Favorite, that couldn't be
any worse for Compromise than if I'd not top-rated
Favorite...because top-ratings aren't conditional.<br>
</div>
<div><br>
</div>
<div>FBC and CD--That's a strong combination. <br>
<br>
</div>
<div>And the addition of that natural conditional feature to
Bucklin is briefer & simpler to define than 3-Slot ICT.
Probably suitable for a first replacement of Plurality.<br>
<br>
</div>
<div>With both methods, if you middle-rate Compromise in 3-Slot
ICT, or conditionally approve Compromise in Conditional
Bucklin, you aren't fully protecting Compromise.<br>
<br>
</div>
<div>Compromise could lose to Worst because you aren't helping
hir get a top-majority in Conditional Bucklin. ...or because
you didn't protect hir from truncation in 3-Slot ICT.<br>
<br>
</div>
<div>Neither has the amount of protection of a 2nd-rated (or
2nd-ranked) candidate in MMPO largely because neither has
wv-strategy. But, of course MMPO would have little chance of
acceptance....whereas Conditional Bucklin could be a
successful Bucklin proposal, due to the naturalness of the
conditional refinement.<br>
<br>
</div>
<div>Your objection to MMPO is of course a perfectly valid one.
If people don't bother to ensure that less-liked candidates
have maximum possible pairwise opposition, then Hitler could
win because two people support him.<br>
<br>
</div>
<div>For hauling, a truck has advantages over a car, but there
are various special dangers & precautions for driving a
truck, as opposed to a car.<br>
</div>
<div><br>
</div>
<div>It's a trade-off. I admit that the price for FBC, Weak CD,
& wv-strategy is high.<br>
<br>
</div>
<div>By the way, if there's a special "favorite-designation" on
the ballot, separate from the ratings, then even a top-rating
could be made conditional (upon the conditionally-top
candidate having more favorite-designations than your
favorite-designated candidatge)<br>
<br>
</div>
<div>And, with that separate favorite-designation on the ballot,
there could be Conditional-Approval.<br>
<br>
</div>
<div>I notice that there are two e-mail addresses for EM. I'm
sending this post to both addresses. If it posts twice, I'll
know that they both work.<br>
</div>
<div><br>
.Michael Ossipoff<br>
<br>
</div>
<div><br>
<br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, Nov 3, 2016 at 8:53 AM,
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>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">I normally
don't like explicit strategy devices, and (beyond
considering it desirable to elect from the<br>
voted Smith set) don't care very much about the "center
squeeze" effect.<br>
<br>
(I like truncation resistance, so I'm happy with some of the
methods that meet the Chicken Dilemma criterion.)<br>
<br>
Nonetheless here is version of IBIFA with a device aimed
at addressing the Chicken Dilemma scenario.<br>
<br>
* Voters mark each candidate as one of Top-Rated, Approved,
Conditionally Approved, Bottom-Rated. Default is
Bottom-Rated.<br>
<br>
A candidate marked "Conditionally Approved" on a ballot is
approved if hir Top Ratings score is higher than the highest<br>
Top Ratings score of any candidate that is Top-Rated on that
ballot.<br>
<br>
Based on the thus modified ballots, elect the 3-slot IBIFA
winner.*<br>
<br>
("Top-Rated" could be called 'Most Preferred' and
"Bottom-Rated" could be called 'Unapproved' or 'Rejected').<br>
<br>
To refresh memories, IBIFA stands for "Irrelevant-Ballot
Independent Fall-back Approval", and the 3-slot version goes
thus:<br>
<br>
*Voters rate candidates as one of Top, Middle or Bottom.
Default is Bottom. Top and Middle is interpreted as
approval.<br>
<br>
If any candidate X is rated Top on more ballots than any
non-X is approved on ballots that don't top-rate X, then the
X<br>
with the highest Top-Ratings score wins.<br>
<br>
Otherwise the most approved candidate wins.*<br>
<br>
<a moz-do-not-send="true"
href="http://wiki.electorama.com/wiki/IBIFA"
rel="noreferrer" target="_blank">http://wiki.electorama.com/wik<wbr>i/IBIFA</a><br>
<br>
35: C<br>
33: A>B<br>
32: B (sincere might be B>A)<br>
<br>
In the scenario addressed by the Chicken Dilemma criterion,
if all (and sometimes less than all) of A's supporters only
"conditionally"<br>
approve B then the method meets the CD criterion. Otherwise
it meets the Minimal Defense criterion.<br>
<br>
<a moz-do-not-send="true"
href="http://wiki.electorama.com/wiki/Chicken_Dilemma_Criterion"
rel="noreferrer" target="_blank">http://wiki.electorama.com/wik<wbr>i/Chicken_Dilemma_Criterion</a><br>
<br>
<a moz-do-not-send="true"
href="http://wiki.electorama.com/wiki/Minimal_Defense_criterion"
rel="noreferrer" target="_blank">http://wiki.electorama.com/wik<wbr>i/Minimal_Defense_criterion</a><br>
<br>
Of course it meets the Plurality criterion and doesn't have
any random-fill incentive.<br>
<br>
The downside is that the use of Conditional Approval can
cause a vulnerability to Push-over strategy.<br>
<br>
48: C<br>
27: B<br>
25: A>>B<br>
<br>
The A supporters are all only conditionally approving B, but
that has the same effect as normal approval because B has a
higher Top Ratings score<br>
than A. But now if 3 to 22 of the C voters change to C=A
then A's Top Ratings score rises above B's so the
"conditional" approval is switched off<br>
and then C wins.<br>
<br>
I dislike this "at the same time"-no-help failure, but the
new result doesn't look terrible and of course if the B
voters really prefer A to C then<br>
they were foolish not to conditionally approve A. If they'd
done that then the attempted Push-over would have just
elected A.<br>
<br>
(It crossed my mind to try to make Push-over strategising
more difficult and riskier with the same mechanism I
suggested a while ago for IRV<br>
or Benham that allows above-bottom equal-ranking, but that
would have broken compliance with FBC.)<br>
<br>
Chris Benham<br>
<br>
</blockquote>
</div>
<br>
</div>
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