[EM] FBC, center squeeze, and CD

Tue Nov 8 08:22:35 PST 2016

On 11/7/2016 6:18 PM, Michael Ossipoff wrote:
>
>
> On Sun, Nov 6, 2016 at 11:24 PM, C.Benham <cbenham at adam.com.au 
> <mailto:cbenham at adam.com.au>> wrote:
>
>     On 11/7/2016 6:07 AM, Michael Ossipoff wrote:
>>     ...someone could say. "You didn't just favor X. You added a
>>     ballot, thereby spoiling a majority. It has nothing to do with
>>     the fact that you voted for X. You could have plumped for any of
>>     various candidates, and the effect would have been exacsly the same."
>
>     "Someone" could /say/ that, but it wouldn't make any sense.
>
>
> But how so?
>

C: Failing mono-add-plump is as stupid as a quasi-"intelligent" device 
can be, in a pure and starkly obvious way, and with the lamest possible 
excuse.

The algorithm/device decides that X should win, and then receives some 
more ballots that contain nothing whatsoever but the pure and simple 
message:
"You are right! X should win" and responds with the bizarre malfunction 
"I've changed my mind, Y should win" and offers the nonsensical excuse 
"Hey those
extra ballots didn't just say that X should win. They also increased the 
total number of ballots!".

> C: What (arguably) desirable properties (or criterion compliances)  
> are incompatible with meeting Mono-add-Plump?
>
> Mike: FBC, CD, & wv-like strategy are evidently require failing 
> Mono-Add-Plump, or having MMPO's Hitler-with-2-votes problem.
>
> With MDDTR, the price of FBC, CD & wv-like strategy is Mono-Add-Plump.

C: There are methods that meet  FBC and CD and mono-add-plump. So your 
proposition boils down to saying that it's worth giving up compliance with
mono-add-plump just to gain "wv-like strategy".

That argument is impossible to make. And it isn't clear to me that 
"wv-like strategy" is even something we should take if it was free.

Chris Benham

>
>
>>     But you can't say anything like that to to explain why X lost
>>     when I raised hir in my ranking. In that instance, making the
>>     ballot-set more favorable to X is the _only_ thing that I'm doing.
>
>     Increasing the turnout is generally regarded as a good thing.  If
>     the method used was one of the mono-raise failing methods I like
>     (such as IRV and Benham), I would say:
>
>     "Unfortunately it isn't possible for voting methods to have every
>     desirable property (because some of those properties are mutually
>     incompatible), and this method economises
>     by not meeting mono-raise.
>
>
> Exactly. The more properties, important desirable ones, a method 
> provides, the more of a cost there is, in terms of "embarrassment 
> criteria", "could-look-bad".
>
> So it's a matter of what you're getting in terms of the 
> "could-look-bad", and whether that could-look-bad could be bad in a 
> practical way. As you suggested, MMPO's "Hitler-with-2-votes" would be 
> bad news, and, as you suggested, is more than a "look-bad".
>
> But the Mono-Raise failure of Benham, Woodall & IRV is only a 
> could-look-bad. It never bothered me, and never stopped me from saying 
> good things about those methods.
>
> Likewise the lesser look-bad of MDDTR, when it fails Mono-Add-Plump.
>
> MDDTR meets FBC & CD, and it has wv-like strategy.
>
> ...the same advantages that MMPO has.
>
> ...at the cost of Mono-Add-Plump.
>
> You like IRV, Benham & Woodall. Lots of people here love IRV. I don't 
> reject those methods, though they aren't my main proposals, because of 
> FBC, and the fact that there's nothing the CWs's voters can do to 
> protects hir from losing, and the fact that Benham & Woodall are 
> pairwise-count methods very vulnerable to pairwise-count offensive 
> strategy, and innocent, nonstrategic truncation.
>
> If you aren't majority-favored, the elimination of the CWs is 
> disadvantages for you. But, in Bucklin, sometimes it might not be 
> known who the CWs is, and s/he might not defenseiveliy plump, and so 
> s/he (& you too) lose anyway, even though it isn't IRV. I don't know 
> that the Bucklin failure that I just described will be rarer than the 
> IRV failure that I just described. And IRV brings some big advantages 
> for people who are majority-favored...MMC, CD, LNHa, LNHe.
>
> If your candidate is big enough to eliminate the CW, then s/he's big 
> enough that s/he's fairly well-known, and that CW's voters would know 
> something about hir, and would be unlikely to reject hir & transfer 
> the other way when s/he's close enough to what you want that you'd 
> prefer to elect hir.
>
> So I don't reject IRV--I just don't emphasize it as a proposal.
>
> Anyway, as I said, lots of people here love IRV, and its Mono-Raise 
> failure doesn't seem to hurt its popularity. You like IRV, and its 
> Mono-Raise failure doesn't put you off from it. I agree with you on that.
>
> And, for the same reason, we needn't & shouldn't be put off by MDDTR's 
> Mono-Add-Plump failure.
>
>
>
>     But generally speaking people care most about their favourites
>
>
> True.
>
>     , and IRV meets not only mono-add-plump but also mono-add-top.
>     It's true that after the election
>     some of losing candidate X's supporters could complain "If we
>     hadn't top-ranked X, then X would have won" but that is unlikely
>     to be noticed and of course isn't
>     true of all (or anything like all) of X's supporters. So the X
>     supporters as a whole could complain "If we had been well informed
>     and coordinated we could have
>     used a mixed strategy (with not all of us voting the same way) and
>     elected X."
>
>     But if voters accept the method as fair and legitimate then that
>     "complaint" won't be taken seriously or get much sympathy.
>
>
> ...as with MDDTR.
>
>
>     Just as no quasi-intelligent device should be so "stupid" as to be
>     confused by the very simple and spectacular MMPO failure example,
>     neither should it be
>     confused by the very very simple mono-add-plump scenario.
>
>
> ...or the fact that in IRV you can make someone lose by ranking them 
> higher?
>
>
>     What (arguably) desirable properties (or criterion compliances) 
>     are incompatible with meeting Mono-add-Plump?
>
>
> FBC, CD, & wv-like strategy are evidently require failing 
> Mono-Add-Plump, or having MMPO's Hitler-with-2-votes problem.
>
> With MDDTR, the price of FBC, CD & wv-like strategy is Mono-Add-Plump. 
> That's a very small price, arguably less than IRV's Mono-Raise failure 
> (though I note that you mentioned that Mono-Add-Plump is about a 
> favorite).
>
> Michael Ossipoff
>
>
>     Chris Benham
>
>
>>     Ok, thanks, Chris, for settling that matter. I guess we have to
>>     reluctantly give up Conditional Bucklin.
>>
>>     But it would have been strategically great!
>>
>>     Now, here's a question on a related topic:
>>
>>     Say I arrive at the polling-place late. Before I arrive X is
>>     winning. I show up & plump for X, and that causes X to lose.
>>
>>
>>     ...is that worse than if I raise X in my ranking, and that causes
>>     X to lose?
>>
>>     If so, why?
>>
>>     It seems to me that the latter is worse than the former.
>>
>>     I if show up late and plump for X, I'm doing two things: I'm
>>     adding a ballot, and I'm voting that ballot in a way that clearly
>>     should favor X.
>>
>>     If i angrily complain, "Hey, how come, when I arrived and plumped
>>     for X, that made X lose??!"
>>
>>     ...someone could say. "You didn't just favor X. You added a
>>     ballot, thereby spoiling a majority. It has nothing to do with
>>     the fact that you voted for X. You could have plumped for any of
>>     various candidates, and the effect would have been exacsly the same."
>>
>>     But you can't say anything like that to to explain why X lost
>>     when I raised hir in my ranking. In that instance, making the
>>     ballot-set more favorable to X is the _only_ thing that I'm doing.
>>
>>     So plainly violating Mono-Raise is worse than violating
>>     Mono-Add-Plump.
>>
>>     Michael Ossipoff
>>
>>
>>
>>     On Sun, Nov 6, 2016 at 10:27 AM, C.Benham <cbenham at adam.com.au
>>     <mailto:cbenham at adam.com.au>> wrote:
>>
>>         The example I just posted of  "IBIFA with an anti-defection
>>         device"  failing FBC I'm afraid also works for both Mike's
>>         suggested
>>         "Conditional Bucklin" and Forest's suggested "TopMiddleBottom".
>>
>>         20: F=C >>B
>>         07: F > C=B   (or, for the sake of Forest's method
>>         suggestion, F >> C=B)
>>         25: B
>>         48: W
>>
>>         All three of these methods elect W, but if the 20 F=C >> B
>>         voters change their rating of F from Top to Middle or Bottom
>>         then the winner changes to B.
>>
>>         Chris Benham
>>
>>
>>
>
>
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