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

Mon Nov 21 15:38:58 PST 2016

Yes, the definition of Simmons' method, MDDA(pt/2) should be added to
Electowiki.

Should Forest get the first option to do that?

Michael Ossipoff

On Mon, Nov 21, 2016 at 6:29 PM, Monkey Puzzle <araucaria.araucana at gmail.com
> wrote:

> Forest, Michael, Chris:
>
> It seems that you are converging toward consensus on a modified version of
> ICA that is equivalent to MDDTR(pt/2), if
>
> Both these methods have scattered definitions on the list that go back
> years, and the current discussion has moved toward something different than
> the ICA description here:  http://wiki.electorama.com/
> wiki/Improved_Condorcet_Approval .
>
> Would it be possible to have a concise restatement/correction of the
> method(s) somewhere, preferably on electorama?
>
> Thank you!
>
>  Frango ut patefaciam -- I break so that I may reveal
>
> On Mon, Nov 21, 2016 at 3:03 PM, Michael Ossipoff <email9648742 at gmail.com>
> wrote:
>
>> "Just the knowledge that a failure of Mono-add-Plump  is theoretically
>> possible could reduce people's enthusiasm for voting and make it more
>> likely that those who like to vote by just plumping for their favourite
>> will stay home."
>>
>> ...or make you rank your favorite last instead of first in IRV because
>> ranking hir first instead of last could make hir lose?
>>
>> ...or just not vote because you know that IRV can act oppositely to
>> changes in your vote?
>>
>> Michael Ossipoff
>>
>> On Sat, Nov 19, 2016 at 12:18 AM, C.Benham <cbenham at adam.com.au> wrote:
>>
>>> On 11/19/2016 3:14 AM, Michael Ossipoff wrote:
>>>
>>> If the more embarrassing Mono-Raise failure doesn't give IRV any
>>> acceptance or enactment problem, then why should the less embarrassing
>>> Mono-Add-Plump failure of MDDTR give MDDTR an acceptance or enactment
>>> problem?
>>>
>>>
>>> Because what you consider more or less "embarrassing" I am sure isn't in
>>> accord with what most people would find unacceptably ridiculous.
>>>
>>> With MDDTR, if your plump for X makes X lose, it's because you added a
>>> ballot. It has nothing whatsoever to do with the fact that you voted
>>> favorably to X.
>>>
>>>
>>> That's right. "You" should have found some way to vote for X without
>>> adding a ballot. Unfortunately removing someone else's ballot when you are
>>> in the
>>> polling station is usually impossible or legally risky.
>>>
>>> Anyway, if IRV is so widely used and successful, then why would
>>> nonmonotonicity be a problem for MDDTR?
>>>
>>>
>>> Because IRV has a traditional and (for many) intuitive algorithm, and a
>>> solid "maximal"  set of criterion compliances and MDDTR doesn't.
>>>
>>> Earlier you attempted to ridicule my observation that MDDTR fails
>>> Irrelevant Ballots Independence by suggesting that might indirectly
>>> motivate a higher
>>> turnout.  Well, just as some might have an interest in promoting that
>>> (for voters who'll ignore the competitive/viable candidates) so as to wash
>>> away
>>> an otherwise likely majority-defeat disqualification so would opposed
>>> forces have an interest in doing the opposite.
>>>
>>> In fact you could have post-election recriminations reminiscent of those
>>> that were aimed at Nader and those who voted for him supposedly allowing
>>> Bush to
>>> win a few years ago. "Those idiots weren't even really interested in who
>>> won, why didn't they just stay home?!" could be the lament.
>>>
>>> Just the knowledge that a failure of Mono-add-Plump  is theoretically
>>> possible could reduce people's enthusiasm for voting and make it more
>>> likely that those who like to vote by just plumping for their favourite
>>> will stay home.
>>>
>>> Whereas IRV doesn't just meet mono-add-plump. It also meet Mono-add-Top.
>>>
>>> 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".
>>>
>>>
>>> Chris Benham
>>>
>>>
>>>
>>> On 11/19/2016 3:14 AM, Michael Ossipoff wrote:
>>>
>>> I don't mean that IRV isn't ok. IRV's Mono-Raise failure doesn't bother
>>> me.
>>> Neither does MDDTR's Mono-Add-Plump failure.
>>>
>>> Voting's purpose is probabilistic anyway. You vote to improve the
>>> probability of a better outcome. The possible nonmonotonicity of IRV
>>> & MDDTR doesn't invalidate that.
>>>
>>> My point, in asking about when you make someone lose by raising hir from
>>> last place to 1st place, was just that IRV is popular and widely used. It's
>>> been used in Australia for a long time, and it's used in a fair number of
>>> cities in this country.  ...and now has been adopted by the state of Maine.
>>>
>>> ...in spite of its Mono-Raise failure.
>>>
>>> If the more embarrassing Mono-Raise failure doesn't give IRV any
>>> acceptance or enactment problem, then why should the less embarrassing
>>> Mono-Add-Plump failure of MDDTR give MDDTR an acceptance or enactment
>>> problem?
>>>
>>> There of course have been objections to IRV, some valid, some not. But I
>>> haven't heard any of the IRV critics in the various cities complain about
>>> its nonmonotonicity. They object to implementation complexity. They
>>> invalidly claim voting complexity. They invalidly complain because
>>> supposedly voting is supposed to be by Plurality. They repealed IRV in
>>> Burlington because of the elimination of a CWv.   But none of the
>>> complaints that I've heard, in cities using it or considering IRV, have
>>> been about its nonmonotonicity.
>>>
>>> Why I say that Mono-Raise failure is more embarrassing:
>>>
>>> With MDDTR, if your plump for X makes X lose, it's because you added a
>>> ballot. It has nothing whatsoever to do with the fact that you voted
>>> favorably to X.
>>>
>>> With IRV, if raising X from bottom to top makes X lose, then X lost for
>>> no other reason than because you helped hir more.
>>>
>>> There are 2 kinds of nonmonotonicity:
>>>
>>> Did you make X lose _in spite of_ voting favorably for hir?
>>>
>>> or
>>>
>>> Did you make X lose _because_ you voted hir more favorably?
>>>
>>> Of those 2 kinds of nonmonotonicity the 2nd one is more of an
>>> embarrassment to the method. There, the method is more directly acting
>>> oppositely to your action.
>>>
>>> Maybe it could be said that the 2nd kind of nonmonotonicity is twice as
>>> embarrassing to the voting-system.
>>>
>>> Anyway, if IRV is so widely used and successful, then why would
>>> nonmonotonicity be a problem for MDDTR?
>>>
>>> I now feel that IRV's (mitigated) problem isn't an unusually high price
>>> for CD, isn't more than the "going rate" for CD. IRV & its derivatives are
>>> at the top of my ranking of method-merit for electorates who want &/or need
>>> ranking.
>>>
>>> Michael Ossipoff
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Fri, Nov 18, 2016 at 1:23 AM, Michael Ossipoff <
>>> email9648742 at gmail.com> wrote:
>>>
>>>> Forest--
>>>>
>>>> You wrote:
>>>>
>>>>>
>>>>> But MAI still fails FBC.
>>>>>
>>>>
>>>> Failing both FBC & CD isn't good.
>>>>
>>>>
>>>>>
>>>>> So to me the best proposal is ICA with default approval cutoff at
>>>>> truncation to help punish burial and truncation with an option to raise the
>>>>> cutoff to withstand a CD attack.
>>>>>
>>>>
>>>> But buriers or truncators could raise that approval cutoff too. Someone
>>>> could bury X under Z without having to approve Z. That loses the deterrence
>>>> that would exist if that burier had to approve Z in order to rank hir over
>>>> someone, as would be so if ranking is counted as approval.
>>>>
>>>> So CD still comes at the cost of a lot less protection against burial,
>>>> or, in ICT's case, trunction too.
>>>>
>>>> But that just means that it isn't _better_ than MDDTR in that regard.
>>>> It doesn't mean that it's worse.
>>>>
>>>> And it doesn't have Mono-Add-Plump failure.
>>>>
>>>> So, the method has CD as MDDTR does, and trades truncation-proofness
>>>> for Mono-Add-Plump.
>>>>
>>>> I value strategy protections more than embarrassment criteria. (But I
>>>> realize that proposal-opponents can use embarrassment criteria criticisms,
>>>> and that proponents aren't likely to be able to afford as much media time,
>>>> to answer the criticisms.)
>>>>
>>>> [Replying farther down] :
>>>>
>>>>
>>>>
>>>>>
>>>>> Here's my version (slightly different from the original):
>>>>>
>>>>> Candidate X strongly beats candidate Y iff
>>>>>
>>>>> the number of ballots on which X is ranked over Y is greater than
>>>>>
>>>>> the number of ballots on which Y is *ranked* equal to or greater than
>>>>> Y.
>>>>>
>>>>> [Note Y is not ranked equal to X if Y is not ranked.]
>>>>>
>>>>> If not all of the candidates are strongly beaten, disqualify all of
>>>>> the ones who are.
>>>>>
>>>>> Elect the most approved qualified candidate.
>>>>>
>>>>> I think that this method has all of the good properties of MDDA with
>>>>> mono-add-plump to boot.
>>>>>
>>>>
>>>> I've only had a preliminary look at it, but it seems to me, right now,
>>>> that the separate approval-cutoff that the voter can raise from the default
>>>> spoils protection from burial & truncation.
>>>>
>>>>
>>>> You wrote:
>>>>
>>>>
>>>>> We still need to explore MDDA with the half power truncation rule,
>>>>> since it would also satisfy mono-add-plump if I am not mistaken.
>>>>>
>>>>
>>>> Yes, it seems to me that a 1/2 power-truncation would get rid of the
>>>> Mono-Add-Plump failure. If, by not ranking a certain 2 candidates, you give
>>>> them each at least half of a vote against eachother, that would bring
>>>> Mono-Add-Plump compliance, it seems to me.
>>>>
>>>> So maybe it would avoid criticism of MDDA.
>>>>
>>>> But, if used with MDDTR, it would spoil CD.
>>>>
>>>> You wrote:
>>>>
>>>>
>>>>
>>>>> I agree with Chris Benham that mono-add-plump failure would be fatal
>>>>> in a public proposal.
>>>>>
>>>>>
>>>> What if you're going to rank X last in your ranking. With all the
>>>> ballots, including yours, X will win. But then you move X to 1st place in
>>>> your ranking, and that makes X lose.
>>>>
>>>> Would that be ok?
>>>>
>>>> Michael Ossipoff
>>>>
>>>>
>>>>
>>>>
>>>>> On Thu, Nov 17, 2016 at 2:12 PM, Michael Ossipoff <
>>>>> email9648742 at gmail.com> wrote:
>>>>>
>>>>>> I meant to ask: Did you say that MTRI doesn't pass FBC? How does FBC
>>>>>> failure happen? In return for FBC, it should beat MDDTR at vulnerability to
>>>>>> burial, and not be vulnerable to truncation.
>>>>>>
>>>>>> Anyway, anything you can tell me about the properties comparison
>>>>>> between MTRI & MDDTR would be helpful.
>>>>>>
>>>>>> MIchael Ossipoff
>>>>>>
>>>>>> On Thu, Nov 17, 2016 at 5:05 PM, Michael Ossipoff <
>>>>>> email9648742 at gmail.com> wrote:
>>>>>>
>>>>>>> For this method, MTRI, the procedural definition is more
>>>>>>> understandable than the recursive definition (though the recursive
>>>>>>> definition's brevity could be useful).
>>>>>>>
>>>>>>> So this is what I understand MTRI's procedural definition to be:
>>>>>>>
>>>>>>> 1. Order the candidates by their top-count score, with higher scores
>>>>>>> at top.
>>>>>>>
>>>>>>> 2. Switch the lowest pair of adjacent candidates whose lower
>>>>>>> candidate pair-beats the higher one.
>>>>>>>
>>>>>>> Repeat till there are no more pairs to switch. The highest candidate
>>>>>>> in the order at that time wins.
>>>>>>>
>>>>>>> -----------------------------------------------
>>>>>>>
>>>>>>> As a CD rank method, this method is a competitor of MDDTR. What are
>>>>>>> the property differences between MTRI & MDDTR?
>>>>>>>
>>>>>>> In particular, how does MTRI compare with MDDTR in regards to
>>>>>>> protection of a CWs against truncation & burial?
>>>>>>>
>>>>>>> Michael Ossipoff
>>>>>>>
>>>>>>>
>>>>>>> On Thu, Nov 17, 2016 at 2:55 PM, Forest Simmons <fsimmons at pcc.edu>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> On Thu, Nov 17, 2016 at 10:54 AM, Michael Ossipoff <
>>>>>>>> email9648742 at gmail.com> wrote:
>>>>>>>>
>>>>>>>>> But wouldn't Smith//Approval, with approval cutoffs in the
>>>>>>>>> rankings, share MDDTR's burial-vullnerability?
>>>>>>>>>
>>>>>>>>> ...with, additionally, vulnerability to truncation, which MDDTR
>>>>>>>>> _doesn't_ have?
>>>>>>>>>
>>>>>>>>> And Smith//Approval trades MDDTR's FBC for Smith, which I consider
>>>>>>>>> an unfavorable trade.
>>>>>>>>>
>>>>>>>>
>>>>>>>> Perhaps make truncation the default approval cutoff, but let voters
>>>>>>>> move it higher as an option:
>>>>>>>>
>>>>>>>> 45 C
>>>>>>>> 30 A>B or A>>B
>>>>>>>> 25 B
>>>>>>>>
>>>>>>>> Voting A>>B would be the chicken defense (where sincere is 25 B>A).
>>>>>>>>
>>>>>>>> Voting A>B would be the truncation defense (where sincere is 45
>>>>>>>> C>B).
>>>>>>>>
>>>>>>>> With this option, MDDA would be an FBC compliant method that is
>>>>>>>> truncation and burial resistant as well as quasi CD compliant.
>>>>>>>>
>>>>>>>> Is there a way to modify MDDA to make it satisfy mono-add-plump?
>>>>>>>>
>>>>>>>> How about incorporating some form of power truncation.  When you
>>>>>>>> plump X and reduce the majority victory of Y over Z to a sub-majority, it
>>>>>>>> would revert to a majority if you counted the common truncation of Y and Z
>>>>>>>> against each other as even half a point.
>>>>>>>>
>>>>>>>> Btw, in case you didn't see it, one of my new favorite non-FBC
>>>>>>>> methods is Most Approved Immune(MAI):  Elect the most approved immune
>>>>>>>> candidate.
>>>>>>>>
>>>>>>>> This means elect the most approved candidate X that is unbeaten
>>>>>>>> pairwise by the candidate that would win (recursively) if the method were
>>>>>>>> applied to the same ballot set with X disqualified or withdrawn.
>>>>>>>>
>>>>>>>> It is the simplest approval based rank method that confers immunity
>>>>>>>> from second place complaints on its winners.
>>>>>>>>
>>>>>>>> It is quasi CD compliant if voters can specify their approval
>>>>>>>> cutoffs above the truncation level when they want to.
>>>>>>>>
>>>>>>>> A top rank version of this method is fully CD compliant:
>>>>>>>>
>>>>>>>> Elect the Most Top Ranked Immune candidate. (MTRI)
>>>>>>>>
>>>>>>>> In other words elect the most top ranked candidate X that is
>>>>>>>> unbeaten pairwise by the candidate that would win (recursively) if the
>>>>>>>> method were applied to the same ballot set with X disqualified or withdrawn.
>>>>>>>>
>>>>>>>> Forest
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>>
>>>
>>
>> ----
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>> info
>>
>>
>
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