[EM] FBC, center squeeze, and CD

Sat Nov 5 15:20:37 PDT 2016

The use of "pairwise-beats" instead of "has more unconditional approvals"
is something to check out.

How does Conditional Approval violate FBC?  Example?

By the way, I'd like to change (unless someone points out why not to) my
rule for giving a conditional vote in Conditional(u) Bucklin, in rounds
after the 1st round:

In rounds after the 1st one (which means at ranks below the 1st one):

A ballot that conditionally ranks a candidate at that rank gives a vote to
hir only if that vote-receiving candidate has a higher vote total (as of
just before that round) than any candidate ranked over hir on that ballot.

Michael Ossipoff

On Sat, Nov 5, 2016 at 5:20 PM, Jameson Quinn <jameson.quinn at gmail.com>
wrote:

> How about this one:
>
> Voters can give approval, conditional approval, or secret approval, or
> disapproval.
>
> Conditional approval is extended to a candidate C on a ballot that
> approves A and B if C pairwise beats both A and B, counting
> approval>conditional approval>secret approval or disapproval.
>
> Highest total wins, where total is approval, conditional approval that's
> extended, and secret approval.
>
> ....
>
> I'm including secret approval above because without it, conditional
> approval violates FBC. I'm using "pairwise beats" rather than "higher
> unconditional approval" because it handles center squeeze.
>
> I realize that explaining why secret approval is a thing makes this system
> impractical as a concrete proposal. But then, you're the one who says FBC
> is non-negotiable.
>
> 2016-11-05 15:41 GMT-04:00 Michael Ossipoff <email9648742 at gmail.com>:
>
>> Because it's so brief, let me state the conditional(u) option, for
>> Approval, and for Bucklin:
>>
>> Approval:
>>
>> If a ballot conditionally approves a candidate, then it gives an approval
>> to that candidate only if that vote-receiving candidate has more
>> unconditional approvals than does any candidate unconditionally approved by
>> that ballot.
>>
>> Bucklin:
>>
>> 1. At 1st rank:
>>
>> In the 1st round, if a ballot gives conditional 1st ranking to a
>> candidate, that 1st ranking is given only if that vote-receiving candidate
>> is unconditionally 1st-ranked on more ballots than is any candidate
>> unconditionally 1st ranked on that ballot.
>>
>> 2. At any rank other than 1st:
>>
>> In a round, at some non-1st rank, if a ballot gives a conditional vote to
>> a candidate, then that ballot gives that candidate a vote in that round
>> only if that vote-receiving candidate has a higher vote-total (as of just
>> before that round) than any candidate unconditionally 1st-ranked on that
>> ballot.
>>
>> Michael Ossipoff
>>
>>
>>
>> On Sat, Nov 5, 2016 at 3:28 PM, Michael Ossipoff <email9648742 at gmail.com>
>> wrote:
>>
>>> Hi Jameson--
>>>
>>> The choice among the 3 goals you name is a subjective choice, with no
>>> wrong choice of goal.
>>>
>>> So we can amicably prefer differfent goal-choices & different solutions
>>> to achieve them.
>>>
>>> To me, FBC is essential.
>>>
>>>  ...because...
>>>
>>> 1.  Many people won't consider not fully helping some compromise (maybe
>>> a really odious "compromise" like Hillary).  At least let them also fully
>>> support their favorite, and other better candidates when doing so.
>>>
>>> 2. Because of the importance of the strong top-set, and maybe the
>>> ordinary top-set too, it's important to always allow the option of
>>> fkully-effective strategically optimal approval-votilng, equal top rating
>>> or ranking.
>>>
>>> #1 applies mostly just to current conditions. #2 applies in any
>>> conditions.
>>>
>>> As you said, reliably electing the CWs (& in rank-methods, the CWv) is
>>> incompatible with FBC. Therefore I reject the Condorcet Crirerion (CC) as a
>>> goal. As you or Chris mentioned, the center-squeeze concern is closely
>>> related to CC.
>>>
>>> It's possible to get CD & FBC. Therefore, a genuinely _best_ method
>>> should have both.
>>>
>>> Because MMPO must reluctantly be abandoned (Chris finally convinced me)
>>> because of its "Hitler with 2 votes" problem, then:
>>>
>>> The best methods are Conditional Approval & Conditional(u) Bucklin.
>>>
>>> ...But I repeat that the choice among your 3 goals is subjective and
>>> individual, and that there's no wrong choice. I'm just stating my own
>>> choice.
>>>
>>> Of course, for a first proposal, for a first reform from Plurality,
>>> brief definition is essential. Also, the easiest possible implementation,
>>> without any new balloting-equipment or software, might be advantageous,
>>> making Approval the best first proposal.
>>>
>>> But, if people want rankings (and many do, and many likely need them, to
>>> soften their voting-errors), then Bucklin has the advantage of relative
>>> brevity, and use-precedence.
>>>
>>> Or, if new balloting & software is feasible (as would be necessary for
>>> Bucklin, then Conditional Approval could be considered.
>>>
>>> Conditional(u) Bucklin, adding some to the definition-length of Bucklin,
>>> might or might not be publicly acceptable, by the public's brevity-standard.
>>>
>>> Michael Ossipoff
>>>
>>>
>>>
>>>
>>>
>>> On Sat, Nov 5, 2016 at 2:32 PM, Jameson Quinn <jameson.quinn at gmail.com>
>>> wrote:
>>>
>>>> We've had some productive discussions recently about methods that
>>>> attempt to deal with FBC, center squeeze, and chicken dilemma. (Note that
>>>> "deal with chicken dilemma" could mean one of two things: punish betrayal,
>>>> or avoid a slippery slope. There are differing opinions as to which of
>>>> these is better.)
>>>>
>>>> But there is a fundamental tension between these three characteristics.
>>>> After all, center squeeze is really just a special case of the Condorcet
>>>> criterion; and FBC and Condorcet are well-known to be incompatible.
>>>>
>>>> Why are those two things incompatible? Because in a Condorcet cycle,
>>>> with a Condorcet-compliant voting system, if the other two groups vote
>>>> honestly, then your faction can guarantee electing your second choice by
>>>> betraying your favorite. So if you expect your least-favorite to win,
>>>> betrayal is strategically forced.
>>>>
>>>> Essentially, in a cycle of 3, sticking with your favorite is a signal
>>>> for the group who likes your second favorite and hates your favorite that
>>>> your favorite is a threat, and they'd better compromise because you're
>>>> unwilling to.
>>>>
>>>> My various recent proposals have tried to thread this needle in
>>>> different ways:
>>>>
>>>> MAS gets FBC, no-slippery-slope CD, and (with some explicit strategy)
>>>> center squeeze, by having two middle ranks: an upper level to signal
>>>> willingness to compromise even with a smaller faction (as in center
>>>> squeeze), and a lower level to signal the idea that you expect the larger
>>>> faction to be correct (as in chicken dilemma).
>>>>
>>>> PAR gets no-slippery-slope CD, strategy-free center squeeze, and comes
>>>> close to (but fails to reach) FBC, by automating the strategic choice for
>>>> middle votes. Unfortunately, that makes it too close to
>>>> Condorcet-compliant, so that FBC breaks.
>>>>
>>>> PAR-prime is basically the same compromise as PAR, but slightly extends
>>>> the cases where center squeeze works, at the cost of a bit more complexity
>>>> of description.
>>>>
>>>> QQQ gets FBC, no-slippery-slope CD, and handles the more clear-cut
>>>> cases of center squeeze, at the cost of EXTREME complexity of description,
>>>> by barely sipping the strategic information from other votes, so that the
>>>> drops of strategic information that your vote leaks to opposing factions
>>>> can be equalled by an ideal FBC-compliant ballot.
>>>>
>>>> Other proposals (ICT, IBIFA, conditional approval, etc.) have other
>>>> interesting attempts to resolve this trilemma.
>>>>
>>>> Essentially, if you have a method that deals with center squeeze and
>>>> no-slippery-slope CD, then there are two possibilities. Either it will be
>>>> using some kind of hard threshold to decide which is which, in which case
>>>> it's possible to make scenarios which will fall on the wrong side of the
>>>> threshold naturally, and in which there could be subgroups whose only way
>>>> to fix things would be favorite betrayal; or it will be resolving things by
>>>> placing the strategic burden on the voters.
>>>>
>>>> One idea which I'd like to explore, but haven't managed to make work
>>>> (yet?), is that of "patching FBC". For instance: take a sysem like PAR or
>>>> PAR-prime, and restore FBC by making some way to cast a ballot that
>>>> essentially says "these are my true preferences, but I realize that in
>>>> order to get the best outcome I may have to help deep-six my true
>>>> favorite". Since the true favorite would still be at the top, and since the
>>>> "help eliminate my favorite" would only kick in if it actually helped, this
>>>> would technically restore FBC.
>>>>
>>>> Another avenue that might be useful is to develop some weakened FBC
>>>> criterion. For instance: "If the other ballots combined with your true
>>>> preferences do not include a Condorcet cycle, there is always a
>>>> strategically-optimal semi-honest ballot". In other words, if there isn't
>>>> an honest CC, there's no motive to create a false one. I'd call this
>>>> criterion "non-paradoxical semi-honesty". This is not exactly strictly
>>>> weaker than FBC, but in practice it mostly is; most FBC-compliant methods
>>>> would pass this criterion. But are there any non-FBC methods which meet it?
>>>>
>>>> ....
>>>>
>>>> OK, here's a proposal. It's PAR-like, it solves the same problem as
>>>> PAR-prime does, but it may be technically FBC compliant:
>>>>
>>>>
>>>>    1. Voters can Prefer, Accept, or Reject each candidate. Default is
>>>>    Accept. For each candidate they prefer, they may also check a "secret"
>>>>    checkbox.
>>>>    2. Candidates with a majority of Reject, or with under 25% Prefer,
>>>>    are eliminated, unless that would eliminate all candidates.
>>>>    3. Candidates with a majority of (public reject plus secret
>>>>    prefer), or with under 25% public prefer are given the label "supposedly
>>>>    eliminated", unless all candidates would be "supposedly eliminated".
>>>>    4. Each candidate gets a point for each ballot where they don't
>>>>    fall below any non-supposedly-eliminated candidates. Most points wins.
>>>>
>>>>
>>>> I think this may meet FBC, if you count secret preference as a kind of
>>>> preference. Basically secret preference is a way of saying "I think I may
>>>> be on the losing wing of a center-squeeze situation, but that the opposite
>>>> wing may not be eliminated. Thus, I want the other voters on my wing to be
>>>> ready to compromise, even if our candidate is apparently viable."
>>>>
>>>> This has all the good characteristics of PAR, except for the additional
>>>> complexity it brings.
>>>>
>>>> Secret preference would not be a favored strategy in any simple
>>>> 3-faction scenario; in fact, I think that it requires a minimum of 4
>>>> factions AND 4 "meaningful" candidates (candidates without whom some
>>>> ballots would not be using the full ratings range). If no candidate can be
>>>> alone at bottom-rank unless they're alone at top rank for some faction, it
>>>> may even take at least 5 factions before "secret" is ever a factor.
>>>>
>>>> In other words: secret preference is only a hacked-up patch to restore
>>>> FBC, and not something that I think would be strategically useful in real
>>>> life.
>>>>
>>>> ...
>>>>
>>>>
>>>>
>>>> ----
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>>>> info
>>>>
>>>>
>>>
>>
>
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