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

Mon Nov 21 15:29:44 PST 2016

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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