[EM] Anti-defection strategy device for IBIFA

[Jameson Quinn]

Could you state Conditional 3-slot Bucklin as you would define it for
somebody who didn't know what "Bucklin" was?

2016-11-04 11:15 GMT-04:00 Michael Ossipoff <email9648742 at gmail.com>:

> I'd said that, like 3-Slot ICT, Conditional Bucklin doesn't let you give
> full protection to the distrusted voters candidate, or to any candidate
> that you merely approve, because you aren't helping hir get a majority.
>
> But then, in a later posting, i said that the favorite-designation
> shouldn't give anything in the points-count, because that would create a
> strategic need to give that favorite designation to a compromise, or to the
> distrusted voters' candidate.
>
> So the favorite designation would be distinct from the ratings that give
> points, such as an Approval ballot, or the 1st rank of a Bucklin ballot.
>
> Well, my 2nd comment fixes the problem that I mentioned in my 1st comment.
>
> Have a favorite-designation that doesn't count for points in any way, and
> whose only use is for determining whether the conditional approval should
> be given.
>
> Below that is the Approval ballot, or the Bucklin ballot, starting with
> its 1st rank position.
>
> Then, the method is Conditional Approval, or Conditional Bucklin, with a
> favorite-designation used only for determining whether the conditional
> approval will be given.
>
> In Conditional Buckllin,  every vote given by a ballot, at every stage of
> the count (or every vote other than the the one given in the 1st round),
> can be conditional, if the voter so marks it.
>
> A special case of that would be 3-Slot Conditional Bucklin, in which, in
> addition to the favorite-designation, the ballot has a 3-Slot Bucklin ballot
>
> As I said last night, at any particular round of Conditional Bucklin, the
> conditional vote would be given if the vote-receiver's vote total, just
> before that round is greater than that of the giving ballot's designated
> favorite with the highest vote total at that time.
>
> But maybe it would be better to only allow a ballot to designate one
> favorite, partly to simplify the count rule, shortening the definition,
> making it easier to propose.
>
> So: Conditional Approval, or Conditional Bucklin--which would include
> Conditional 3-Slot Bucklin.
>
> As I said, no doubt Chris's improved interpretation of majority is indeed
> an improvement, but it's too complicated for a first reform from Plurality.
> It would be a good refinement for later.
>
> When there are two or more candidates getting a majority in a round, or
> when there are no majorities at the end of the count, I prefer declaring
> the winner based on vote-total, rather than top-count.
>
> For one thing it results in a briefer definition.
>
> And it makes the votes given at the various non-top stages of the count
> more effective, which seems more in keeping with Bucklin's purpose..
>
> And it chose D in Forest's example that I was discussing last week.
>
> I understand that using the top-count instead of the vote-total helps the
> chicken dilemma situation some, but it doesn't eliminate the chicken
> dilemma..That's especially ok if the chicken dilemma problem is eliminated
> by Chris's conditional vote option.
>
> Michael Ossipoff
>
>
> On Thu, Nov 3, 2016 at 8:53 AM, C.Benham <cbenham at adam.com.au> wrote:
>
>> I normally don't like explicit strategy devices, and (beyond considering
>> it desirable to elect from the
>> voted Smith set) don't care very much about the "center squeeze" effect.
>>
>> (I like truncation resistance, so I'm happy with some of the methods that
>> meet the Chicken Dilemma criterion.)
>>
>> Nonetheless here is  version of  IBIFA with a device aimed at addressing
>> the Chicken Dilemma scenario.
>>
>> * Voters mark each candidate as one of  Top-Rated, Approved,
>> Conditionally Approved, Bottom-Rated. Default is Bottom-Rated.
>>
>> A candidate marked "Conditionally Approved" on a ballot is approved if
>> hir Top Ratings score is higher than the highest
>> Top Ratings score of any candidate that is Top-Rated on that ballot.
>>
>> Based on the thus modified ballots, elect the 3-slot IBIFA winner.*
>>
>> ("Top-Rated"  could be called 'Most Preferred' and "Bottom-Rated" could
>> be called 'Unapproved' or 'Rejected').
>>
>> To refresh memories, IBIFA stands for "Irrelevant-Ballot Independent
>> Fall-back Approval", and the 3-slot version goes thus:
>>
>> *Voters rate candidates as one of  Top, Middle or Bottom. Default is
>> Bottom.  Top and Middle is interpreted as approval.
>>
>> 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
>> with the highest Top-Ratings score wins.
>>
>> Otherwise the most approved candidate wins.*
>>
>> http://wiki.electorama.com/wiki/IBIFA
>>
>> 35: C
>> 33: A>B
>> 32: B (sincere might be B>A)
>>
>> In the scenario addressed by the Chicken Dilemma criterion, if all  (and
>> sometimes less than all) of A's supporters only "conditionally"
>> approve B then the method meets the CD criterion.  Otherwise it meets the
>> Minimal Defense criterion.
>>
>> http://wiki.electorama.com/wiki/Chicken_Dilemma_Criterion
>>
>> http://wiki.electorama.com/wiki/Minimal_Defense_criterion
>>
>> Of course it meets the Plurality criterion and doesn't have any
>> random-fill incentive.
>>
>> The downside is that the use of  Conditional Approval can cause a
>> vulnerability to Push-over strategy.
>>
>> 48: C
>> 27: B
>> 25: A>>B
>>
>> 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
>> 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
>> and then C wins.
>>
>> 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
>> they were foolish not to conditionally approve A. If they'd done that
>> then the attempted Push-over would have just elected A.
>>
>> (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
>> or Benham that allows above-bottom equal-ranking, but that would have
>> broken compliance with FBC.)
>>
>> Chris Benham
>>
>>
>
> ----
> Election-Methods mailing list - see http://electorama.com/em for list info
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20161104/1f3ad815/attachment-0001.htm>