[EM] Bucklin/IRV hybrid? Motivated by MSV strategy

[C.Benham]

On 10/31/2016 7:48 AM, Michael Ossipoff wrote:

> Of course at EM we discuss two completely separate and different 
> method proposal choices:
>
> 1. Proposals to electorates who have only had Plurality.
>
> 2. Later proposals to replace one better voting system with another.
>
> If we're talking about #1, then there are only a few to choose from:
>
> Approval, Score, and Bucklin.

Mike,

A short time ago you were in favour of CD methods (and even crafted the 
criterion) and said that your
favourite method is ICT  (aka 3-slot TTR, Top Ratings).

So what happened to it?    You even seemed ready to tolerate the 
non-FBC  CD methods Benham and IRV.

> For #2, it really takes something with a lot of valuable & 
> otherwise-unobtainable properties, to justify replacing Approval, 
> Score or Bucklin with it.
>
> I suggest that only Plain MMPO qualifies.

Say you ask people who are used to and/or like any of  Approval, Score,  
Bucklin,  or  plurality (aka FPP) or Top-Two Runoff or IRV or Benham:

(a) Would you accept a method that in a 3-candidate election with 20 
million voters can elect a candidate that is voted above equal-bottom
on only two ballots?

x: A
1: C=A
1: C=B
x: B

x = any number greater than 1.   MMPO  elects C.

(b) Do you think it is fair and sensible that a voter who is only 
interested in getting their favourite elected can increase the chance of 
that
happening by fully ranking (below top) all the other candidates at random?

What response do you think you will get?

I don't live in the US, but I would think that most people wouldn't even 
believe that question (a) is serious, and that anyone who tries to
tell them that that example only "looks bad" would blow their credibility.

Chris Benham




> Jameson--
>
>
> On Sat, Oct 29, 2016 at 11:16 AM, Jameson Quinn 
> <jameson.quinn at gmail.com <mailto:jameson.quinn at gmail.com>> wrote:
>
>
>     ....Here's my "ideal characteristics" for a political
>     single-winner election system, more or less in descending order of
>     importance:
>
>      1. FBC
>
>
> Yes, I consider FBC to be #!.
>
>     1.
>
>
>      2. Handles center squeeze (ie, some form of weakened Condorcet
>         guarantee that's compatible with FBC)
>
> But maybe the goal of electing the CWs unnecessarily complicates 
> votiing. Maybe someday, there won't be a bottom set, for most voters, 
> and, with honest elections & honest, open media, it will be clear 
> who's the CWs. But now, Approval's best strategy doesn't require that. 
> Brams pointed out that Approval's results can be better than the CWs.
>
> But, when it's desirable to elect the CWs, and it isn't obvious who's 
> the CWs, then the wv methods, and methods with wv-like strategy (such 
> as MMPO), are the methods that make it easiest to protect the CWs.
>
> Also, it should be noted that you can't be sure how often there will 
> be a CWs, under different and better conditions.
>
>     1.
>
>
>      2. Relatively simple to explain
>
>
> Approval & Score are easy to explain. I've had conversations in which 
> only Approval & Score were accepted as being plain & un-elaborate 
> enough to be acceptable..
>
> You know that SARA & XA are complicated and not easy to explain. I've 
> tried explaining them.
>
> MMPO?:
>
> "The winner is the candidate who has fewest people voting someone else 
> over hir."
>
> {...some same other candidate)
>
>     1.
>
>
>      2. Minimal strategic burden
>
>
> We often hear it said that Approval has a large strategic burden, but, 
> for most people, with our current candidate-lineup, there's nothing 
> difficult about it: Approve (only) the progressive candidates. That's 
> optimal for most people.
>
> And if the time comes when, for most people, there isn't a bottom-set, 
> then that will be a happy circumstance, in which it doesn't matter 
> terribly anyway, which candidate wins.
>
> In such conditions, with honest elections and honest, open media, it 
> will likely be pretty obvious who's the CWs, and, in the absence of 
> tep-set/bottom-set, the best strategy will be to just approve down to 
> the CWs.
>
> And, if there were no bottom-set, and if it happened that it _wasn't_ 
> clear who the CWs was, and it was 0-info, then it would just be a 
> matter of approving down to the expected winning merit-level. Maybe, 
> under those conditions, that would be the candidate-mean.  Or maybe 
> (as now)  the estimated mean merit of what voters want (which can be 
> estimated by the candidates' merit-midrange, if the election is 1D.  
> ....but it might not remain 1D under different and better conditions).
>
> ..but I repeat that, with only your former top-set remaining as 
> winnable candidates, it won't make as much difference which one wins 
> anyway.
>
> People often consider Approval voting more difficult than it is.
>
>
>      1. Summable (ideally O(N), no worse than O(N²) in practice,
>         though I might accept some special pleading for the use of
>         prior polling to reduce to O(N²).)
>      2. Handles CD, or at least, CD offensive strategies don't in
>         practice mess up the center squeeze properties.
>
>
> MMPO meets Weak CD.
>
>     1.
>
>
>      2. Some arguable track record
>
>
> Of course at EM we discuss two completely separate and different 
> method proposal choices:
>
> 1. Proposals to electorates who have only had Plurality.
>
> 2. Later proposals to replace one better voting system with another.
>
> If we're talking about #1, then there are only a few to choose from:
>
> Approval, Score, and Bucklin.
>
>
> I suggest that all 3 of those should be offered to initiative-proposal 
> committees, and that the public should be polled, or consulted in 
> "focus-groups", regarding which of those 3 methods they'd  accept
>
>
> For #2, it really takes something with a lot of valuable & 
> otherwise-unobtainable properties, to justify replacing Approval, 
> Score or Bucklin with it.
>
> I suggest that only Plain MMPO qualifies.
>
>
>
>     1.
>
>
>
>
>      Approval does well on 1,3,4, and 6, is OK on 2, and bad on 4 and 5.
>
>
>
> No. Contrary to what we so often hear, Approval doesn't have a high 
> strategic burden, as I discussed above.
>
> Other than MMPO's CD, improvements over Approval by more complicated 
> methods are illusory.
>
> And your standard #5 was summability and count-complexity. Approval is 
> precinct-summable, and its count is the easiest and least 
> computation-intensive, among voting-systems.
>
> Michael Ossipoff
>
>
>
>
>
>

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