[EM] Trying to have CD, protect strong top-set, and protect middle candidates too

[Michael Ossipoff]

I said:

"But, especially if the method wouldn't always be used in that way, MDDA
would be a lot safer from an embarrassing & bad result due to its poor
protection from burial."

I meant:

"...a lot safter from an embarrassing & bad result like the one that could
happen in MDDTR, due to its poor protection from burial."

Michael Ossipoff

On Wed, Nov 16, 2016 at 9:21 PM, Michael Ossipoff <email9648742 at gmail.com>
wrote:

> Alright, thanks!  That answers my question about how one of your
> Approval/Pairwise proposals (Pairwise-Sorted Approval)  relate to these
> goals, and it means that, there's a good,brief and natural definition
> that's equivalent to Smith//Approval.
>
> That's briefly-defined enough to be in the list of methods that should be
> offered to the public and to the initiative proposal committee when a
> voting-system reform is being considered.
>
> Your other Approval/Pairwise method that I remember, the Approval
> Cover-Ladder method, is probably too complicated though.
>
> I'm looking at some of the old proposals, including MDDA, MDDTR, MAMPO,
> MMD-Bucklin, etc, that might do well by the standards that I spoke of.
>
> I personally prefer MDDTR to MDDA, if people only use below-top ranking
> when absolutely necessary in a chicken-dilemma situation. ...because I'd
> rather have CD than routine use of middle ranking.
>
> But, especially if the method wouldn't always be used in that way, MDDA
> would be a lot safer from an embarrassing & bad result due to its poor
> protection from burial.
>
> Michael Ossipoff
>
>
>
> On Wed, Nov 16, 2016 at 5:30 PM, Forest Simmons <fsimmons at pcc.edu> wrote:
>
>> Here's a simple method that is essentially Smith//Approval without having
>> to mention the Smith set:
>>
>> List the candidates in order of approval, highest to lowest, top to
>> bottom.  While any candidate pairwise beats an adjacent candidate higher in
>> the list, switch places of the two lowest out of order adjacent members.
>>
>> When there remains no out of order adjacent pair, elect the candidate at
>> the top of the list.
>>
>> Note that the winner will automatically be a member of the top cycle, and
>> if it is a cycle of three, it will be the most approved member of the cycle.
>>
>> Also notice that it yields an unambiguous social order, and that there
>> can be no second place complaint.
>>
>> On Tue, Nov 15, 2016 at 5:19 PM, Michael Ossipoff <email9648742 at gmail.com
>> > wrote:
>>
>>> When I started my current EM participation, I was saying that 3-Slot ICT
>>> was my favorite method.
>>>
>>> That doesn't conflict with saying that I consider Approval the best,
>>> because I regard 3-Slot ICT, or unlimited-rankings ICT (when used
>>> approval-like) as an Approval version without chicken-dilemma.
>>>
>>> Later I realized that MDDTR is better than ICT, because it gives better
>>> protection to middle candidates.
>>>
>>> I measure that protection by how well they'd be protected if they were
>>> CWs.  ...what it would take to protect their win, and how well it's
>>> protected.
>>>
>>> I define "middle candidates" as candidates you rank or rate below top
>>> and above bottom.
>>>
>>> ICT gives no protection to middle candidates, against burial, or even
>>> against innocent, non-strategic truncation--the two things that threaten a
>>> CWs in pairwise-c0unt methods.
>>>
>>> MDDTR gives full truncation-proofness to middle candidates, but
>>> (contrary to what I earlier believed), its protection of middle candidates
>>> against burial can only be called "shabby".
>>>
>>> By the way, I no longer think that ICT or MDDTR needs to be 3-slot.
>>> 3-Slot would be fine with me, because I believe that ICT or MDDTR should be
>>> used as Approval, and that middle rating or ranking should only be used
>>> when seriously needed to deter chicken-dilemma defection. When middle is
>>> used in an unlimited-ranking MDDTR or ICT, it should probably consist of
>>> 2nd-place ranking, if you want to give the demoted candidates the best
>>> protection.   ...but maybe you'd rather rank them with respect to
>>> eachother, at different middle levels, as I probably sometimes would.
>>>
>>> But, as I've been saying, activists & organizations seem to like
>>> rankings, and some people--overcompromisers & rival parties--might very
>>> well need rankings to soften their voting errors.
>>>
>>> And it seems to me that there's no particular reason not to rank, in
>>> order of preference, your middle candidates, if some of them are better
>>> than others, or if the voters of some of them are less trustworthy than
>>> others.
>>>
>>> So, that's if you want CD, in addition to FBC, and good protection for
>>> middle candidates
>>>
>>> Even if you're using the method as Approval, you still want your demoted
>>> candidate(s) to be well protected. Just because you don't trust hir voters
>>> doesn't mean you want to throw her to the hounds and thereby lower Pt, the
>>> probability of electing from your strong top-set.
>>>
>>> Anyway, so far, this is all referring to CD methods.
>>>
>>> Of those, I like MDDTR best. As a rank method, it (as i said) gives only
>>> shabby burial-protection to a middle candidate. But evidently (please tell
>>> me it isn't so) you can't have FBC, CD, and good protection of middle
>>> candidates.
>>>
>>> I consider CD more important to how well protected middle candidates
>>> are. Yes, FBC + CD give poor protection to middle candidates, and that
>>> lessens the value of their CD. But non-CD methods don't have CD at all, and
>>> that's worse.
>>>
>>> So I prefer MDDTR to methods that give better protection to middle
>>> candidates, but don't have CD.
>>>
>>> So, where I used to say that my favorite method is 3-Slot ICT, now I say
>>> that my favorite method is MDDTR. Preferably with unlimited rankings.
>>> (Though one could use only the 1st, 2nd, & bottom positions if one chose
>>> to).   ...regardable as a chicken-dilemma-free version of Approval.
>>>
>>> ------------------------------------------------------------------
>>>
>>> Non-CD methods with better "middle-strategy" than CD methods:
>>>
>>> But, in an election, I'm just one voter, and so, how well-suited the
>>> method is to me is less important, and won't affect the outcome as much, in
>>> comparison to how well-suited the method is to lots of progressives.
>>>
>>> So, what if most progressives would rather have a method that's really
>>> good as a rank method, a method that has good "middle strategy" (strategy
>>> for protecting a middle candidate's win if s/he's CWs).
>>>
>>> That would be important if you knew that all or nearly all, or even most
>>> of them were going to use the method purely as a rank method.
>>>
>>> Bucklin is the traditional FBC rankings-method.
>>>
>>> I distinguish 2 kinds of middle strategy merit:
>>>
>>> 1. How well the method protects top-ranked candidates against
>>> middle-ranked candidates. I call that "Middle1"
>>>
>>> 2. How well the lmethod  protects a middle-ranked candidate against any
>>> candidate you rank lower than hir. I call that "Middle2".
>>>
>>> So, how to get the best middle strategy, with the main goal still being
>>> keeping a good probability, Pt, of electing from your strong top-set?
>>>
>>> MDDTR's middle1 seems better than that of Bucklin. In MDDTR, you're
>>> voting to contribute to a majority for your top against your middle. In
>>> Bucklin, you can protect top against middle by skipping some rating-levels
>>> above the middle candidates. In that way, you can give the top candidates
>>> time to receive the coalescing lower-choice votes that they'll get from the
>>> preferrers of other candidates, before giving anything to the middle
>>> candidates.
>>>
>>> That's a bit more work than just ranking in order of preference. It
>>> requires you to judge where, and how far down in rankings, your top
>>> candidates are going to receive lower-choice votes from.
>>>
>>> So I suggest that MDDTR does better at Middle1 than Bucklin does.
>>>
>>> But Bucklin does better at Middle2.
>>>
>>> In Bucklin, the CWs's win is protected by the people who pretty-much
>>> agree with you, the people of your wing, merely not ranking down too far.
>>>
>>> MDDTR needs that too, but it isn't enough to give MDDTR more than shabby
>>> protection.
>>>
>>> ...And Bucklin's Middle1, though not as convenient or easy as that of
>>> MDDTR, isn't as questionable as MDDTR's Middle2.
>>>
>>> So, overall, I'd say that Bucklin's Middle Strategy is better than that
>>> of MDDTR. So, for people who want to use the method purely as a
>>> rank-method, Bucklin is better than MDDTR.
>>>
>>> Bucklin also has the advantage of use-precedent.  MDDT has the advantage
>>> of precinct-summability,but I don't consider that essential.
>>>
>>> For voters using the method purely as a rank method, I'd prefer Bucklin
>>> to MDDTR.
>>>
>>> Chicken dilemma won't happen all the time, probably won't happen often.
>>> But middle-protection will always matter to people using it as a rank
>>> method.
>>>
>>> But it seems to me that, once we give up CD (for voters who need good
>>> middle strategly, because of their rank voting), then it might be possible
>>> to do better than Bucklin.
>>>
>>> It seems to me that methods that use both Approval and pairwise-count
>>> can do better than Bucklin, at middle protection.
>>>
>>> A lot of methods of that kind have been proposed, and I've ignored all
>>> of them because they don't meet CD. But, as mentioned above, for some
>>> electorates, middle strategy could be more important.
>>>
>>> It seems to me that MDDA (also evidently named MPOA) and Smith//Approval
>>> are two methods that might be better than Bucklin at middle protection..
>>>
>>> Using Approval as the cycle-solution is a very powerful idea (if you're
>>> willing to give up CD, for an electorate's needs). But most of you already
>>> knew that, before I paid attention to it (...because I was only looking at
>>> CD methods)..
>>>
>>> MDDA's & Smith//Approval's burial vulnerability doesn't matter much,
>>> when the Approval winner wins the cycle. In fact, Smith//Approval's
>>> truncation-vulnerability could even be regarded as an advantage, for when
>>> your strong top-set doesn't include the CWs.
>>>
>>> MDDA & Smith//Approval look better to me than Bucklin.
>>>
>>> Simpler Middle1.
>>>
>>> Precinct-Summability is an added bonus.
>>>
>>> MDDA seems to have a briefer definition than either Bucklin or
>>> Smith//Approval, and brief definition can be decisive.
>>>
>>> I know of Bucklin being rejected when MDDTR was accepted. MDDA would
>>> almost surely have been accepted too.
>>>
>>> I don't  think Smith//Approval would go over well, with its need to
>>> define the Smith set, which greatly lengthens the definition.
>>>
>>> For an electorate that need good Middle1 & Middle2 more than CD, MDDA
>>> seems the winner so far.
>>>
>>> Smith//Approvsl of course meets Smith.  ...which of course means that it
>>> fails FBC. But does it need FBC?
>>>
>>> It could be argued (but I don't know if it's true) that Smith//Approval
>>> doesn't need FBC, because, though you don't have an efffective Approval
>>> vote at the top, you still can vote Approval, with the approval-cutoff, or
>>> by only ranking your strong top-set.
>>>
>>> So, though Compromise could become pair-beaten by Favorite because you
>>> raise Favorite to top with Compromise, resulting in a cycle instead of a
>>> CWv win for Favorite, the cycle will be judged by approvals, and you're
>>> approved only your strong top-set.
>>>
>>> Of course, just because Favorite was almost the CWv doesn't necessarily
>>> mean that s/he'll win the Approval count. But are you any worse off than
>>> you'd have been with MDDA?
>>>
>>> Forest (but maybe others too) has proposed a number of methods that
>>> combine pairwise-count and Approval. Do any of those beat MDDA &
>>> Smith//Approval by the standards of protecting one's strong top-set, and
>>> Middle1 & Middle2?
>>>
>>> in particular, do any of them do better than MDDA by those standards? Do
>>> any do as well as MDDA by those standards and have as brief a defintion, or
>>> nearly as brief a definition?
>>>
>>> In other words, are there methods that achieve those things better than
>>> MDDA & Smith//Approval, or achieve them better than MDDA and have as brief
>>> a definition?
>>>
>>> In fact, is there a method that meets FBC (or doesn't need it), meets
>>> CD, and does as well by Middle1 & Middle2 as MDDA, Smith//Approval or
>>> Bucklin?
>>>
>>> Michael Ossipoff
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20161117/dbd55d17/attachment-0001.htm>