[EM] FBC, center squeeze, and CD

[Michael Ossipoff]

In my IRV Mono-Raise failure example:

When I said:

33: A
29: B
30: C

II meant:

33: A
29: B>C
30: C>A

Michael Ossipoff

On Mon, Nov 7, 2016 at 4:47 PM, Michael Ossipoff <email9648742 at gmail.com>
wrote:

> Chris, would your IBIFA interpretation of majority further improve MDDTR,
> by keeping its FBC & CD, while avoiding the (unimportant) Mono-Add-Plump
> failure?
>
> Michael Ossipoff
>
> On Mon, Nov 7, 2016 at 4:44 PM, Michael Ossipoff <email9648742 at gmail.com>
> wrote:
>
>> I should re-state the definition of MDDTR, because we haven't discussed
>> it for a while.
>>
>> Ii don't know who introuced MDDTR. Who introduced it?
>>
>> MDDTR stands for Majority Defeat Disqualification, Top Ratings.
>>
>> MDDTR:
>>
>> Voters can rank as many or as few candidates as they want to.
>>
>> Equal rankings allowed.
>>
>> 1. Disqualify any candidate who has a majority pairwise defeat, unless
>> everyone has one.
>>
>> 2. The winner is the un-disqualified candidate top-ranked by the most
>> voters.
>>
>> [end of definition]
>>
>> MDDTR meets FBC & CD, an has wv-like stratgy.
>>
>> The cost for that is that MDDTR fails Mono-Add-Plump. I've discussed what
>> that is no worse than IRV's failure of Mono-Raise. If IRV can be popular in
>> spite of Mono-Raise failure, and its favorite-burial need, then MDDTR's
>> Mono-Add-Plump failure shouldn't have its importance & badness exaggerated.
>>
>> IRV is popular here. Then there's no reason why MDDTR couldn't or
>> shouldn't be at least as popular.
>>
>> Michael Ossipoff
>>
>>
>>
>> On Mon, Nov 7, 2016 at 4:32 PM, Michael Ossipoff <email9648742 at gmail.com>
>> wrote:
>>
>>>
>>> Chris--
>>>
>>> You suggested that Mono-Add-Plump failure is worse than Mono-Raise
>>> failure because people care more about their favorites, and because
>>> Mono-Raise failure is simpler.
>>>
>>> 1. Caring about favorites:
>>>
>>> a) So you're saying that Mono-Raise failure can't happen when someone
>>> sincerely moves their favorite to top?:
>>>
>>> IRV:
>>>
>>> 31: A
>>> 2: B>A (sincere is A)
>>> 29: B>C
>>> 30: C>A
>>>
>>> 1st round totals:
>>>
>>> A = 31
>>> B = 29 + 2 = 31
>>> C = 30
>>>
>>> C is eliminated & transferss to A
>>>
>>> Now A has a 61 majority and wins.
>>>
>>> But then the 2 B>A voters decide to sincerely raise A to top:
>>>
>>> 33: A
>>> 29: B
>>> 30: C
>>>
>>> B gets eliminated, and transfers to C.
>>>
>>> Now C has a 59 majority and wins.
>>>
>>> b) You care about favorite? What about when you need to rank Comprmise
>>> over favorite to keep worst from winning? We're all familiar with that. In
>>> Burlington, the Republicans didn't do that, and their failure to
>>> favorite-bury elected their last choice.
>>>
>>> Yes, this isn't a monotonicity failure, but you used caring about
>>> Favorite as an advantage of IRV's Mono-Raise failure over MDDTR's
>>> Mono-Add-Plump failure. But obviously IRV has a bigger problem for
>>> Favorite. ...the reason why IRV was repealed in Burlington.
>>>
>>> So please, let's not use caring about Favorite as a reason to prefer IRV
>>> with its Mono-Raise failure
>>> & its favorite-burial need, to MDDTR's Mono-Add Plump failure.
>>>
>>> 2. Simplicity:
>>>
>>> What could be simpler than your need, in IRV, to bury your favorite to
>>> help Compromise beat Worst:
>>>
>>> Sincere:
>>>
>>> 40: C
>>> 25: B>C
>>> 35: A>B
>>>
>>> A voters vote sincerely, and B, the CWv, gets eliminated & transfers to
>>> C. C wins because the A voters didn't favorite-bury.
>>>
>>> Strategic:
>>>
>>> 40: C
>>> 25: B>C
>>> 35: B>A (sincere is A>B)
>>>
>>> Now B wins.
>>>
>>> That's as simple as it gets. Let's not say that MDDTR's look-bad
>>> criterion-failurle is simpler than IRV's serious favorite-burial need.
>>>
>>> Yes, I'm talking about a problem that isn't a monotonicity problem. But
>>> its at least as simple as MDDTR's Mono-Add-Plump problem, and is worse
>>> because it's a practical strategy problem that makes people need to
>>> favorite-bury.
>>>
>>> Michael Ossipoff
>>>
>>>
>>> By sincerely raising A to top, you made A lose.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Mon, Nov 7, 2016 at 2:48 AM, Michael Ossipoff <email9648742 at gmail.com
>>> > wrote:
>>>
>>>>
>>>>
>>>> On Sun, Nov 6, 2016 at 11:24 PM, C.Benham <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?
>>>>
>>>>
>>>>>
>>>>> 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
>>>> thins 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> 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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