[EM] MUMA like method with MJ style ballots

Jameson Quinn jameson.quinn at gmail.com
Wed Oct 5 04:35:59 PDT 2016

I think Forest's proposed method is quite a good one in practice. But as
soon as you bring pairwise into the picture, you fall into a trilemma:
1. If you do pairwise between more than two candidates, you need a
Condorcet tiebreaker, and so complexity explodes.
2. If you do pairwise between two candidates selected by different ballot
thresholds, then only one of the chicken-dilemma allies will make it; this
means that the chicken problem will be as bad as in approval.
3. If you do pairwise between the top two candidates at one ballot
threshold (ie, above-bottom), then you encourage cloning.

Forest's proposal falls into 2. Personally, I think 3 is the best of those
options. For instance, I'd like a 3-slot "pairwise winner of the most
acceptable" (PWMA) method: 3-slot ballots, elects pairwise winner between
the two with fewest explicit bottom-ranks.

Or, for a system that falls into 1, "pairwise MUMA": eliminate as in MUMA,
choose the CW if one exists, otherwise fall back to MUMA (most upvotes).

I think any system falling into 1 or 3 will in practice get results as good
as MUMA. In fact, slightly better: it helps deal with center squeeze.

I have my doubts about 2; it could spoil over chicken strategy.

Also, a minor point: any method that brings a pairwise race into account is
n²-summable, not n-summable. This has implications for ballot-counting

All in all, though, I still favor MUMA as the simplest robust system that
beats approval.

2016-10-04 20:52 GMT-04:00 Forest Simmons <fsimmons at pcc.edu>:

> How about Grade style ballots as in Majority Judgment, but simple MUMA
> style counting:
> Each voter assigns grades A, B, C, D, or F to each of the candidates.  A
> blank counts as an E, between D and F.
> Elect the pairwise winner between the candidate with the greatest number
> of votes above C (pretty good), and the greatest number of votes above D
> (not too bad)
> It seems to me that this simple method would be even more apt than MJ to
> elicit sincere ballots.  In fact, if the pretty good (PG) and not too bad
> (NTB) marks were not strictly required to be consistent with the grade
> marks, then there would be no incentive to vote insincere grades or to
> collapse preferences beyond the built in resolution constraint
> corresponding to only six levels.
> It would be fun to see if voters did vote their grades consistent with
> their PG and NTB marks when not required to.
> For more resolution in the pairwise comparison allow grades with plus (+)
> or minus (-) attached.
> And while we're proposing simple methods, don't forget basic single winner
> asset voting as first advocated by Charles Dodgson (aka Lewis Carroll).
> Forest
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