# [EM] Fwd: (3) MJ -- The easiest method to 'tolerate'

Tue Sep 6 13:07:35 PDT 2016

```On 9/7/2016 1:21 AM, Jameson Quinn wrote:

> Let's take a case where IBIFA and DA disagree.
>
> 40: D>...>A,B
> 35: A>B>D
> 25: B>...>A,D
>
> IBIFA elects A; DA elects B.

C:I assume comma means = and ... means one skipped grade.  I suppose,
since "DA" uses 3-slot ballots. that the ballots explicitly mention the
unapproved (bottom-rated)
candidates. In that case I would translate this as:

40: D
35: A>B
25: B

But then IBIFA elects B.   No candidate X's Top-Rating score is higher
than any candidate Y's approval (i.e. above-bottom rating) score on
ballots that don't top-rate X, so
IBIFA elects the most approved candidate, B.

> Obviously, one could tweak these numbers to try to make one or the
> other system look better or worse.

C: Well then I am very curious to see any example where IBIFA "looks
worse" than DA.

> What I'm saying there is that 200:B>>A>C is actually shorthand for
> 180:B>>A>C, 20:B>>C>A.

C: That is very useful and clarifying "shorthand".

>     What is the default rating?
>
>
> There is a complex rule for this.

C:I greatly prefer a very simple rule: the default rating is Bottom
(i.e. the lowest possible).

The rule regarding "the following election" I consider arbitrary and
very undemocratic.

> This is the case where a candidate wins despite the fact that the
> majority of the electorate put them at bottom. If they are to win a
> second term, they must do so as a write-in.

C:That is just ridiculous and unfair and arbitrary. The rule as I read
it didn't just refer to the winner (not that I can accept either
version). A lot can happen in the years between
elections. Why should a candidate be severely disadvantaged because of
how s/he went in the last election?

> Note that AD is pretty similar [to MTA], and arguably farther in the
> direction you're favoring.

I assume "AD" is  a typo and means DA.  Compared with MTA, DA is
needlessly complicated and too (IMO) too focused on the bottoms of the
ballots.

Chris Benham

> Sorry; I sent a premature version of this response to Chris alone.
> This is the same as that, except for this paragraph. The one thing I
> wanted to reemphasize here is that I'm not trying to make this into a
> battle between good systems. IBIFA, Smith//Approval, Schulze, and
> Approval do not belong to the class of single-winner methods I call
> "best" (though IBIFA almost does); but I still consider all of those
> methods extremely good, and would enthusiastically join a campaign for
> their use in some jurisdiction.
>
>
> 2016-09-06 8:56 GMT-04:00 C.Benham <cbenham at adam.com.au
>
>     On 9/6/2016 6:00 AM, Jameson Quinn wrote:
>
>         It's really hard to respond point-by-point as a third party in
>         a discussion like this. However, I'd like to say in general
>         that I believe that Majority Judgment, and more-generally, the
>         class of "median" or "graded Bucklin" systems which includes
>         MJ, MCA, GMJ, ERB, DA, etc., are the best non-delegated
>         single-winner systems for a potentially-strategic electorate,
>         in terms of outcome.
>
>
>     C: How are they better than IBIFA?  Or, say, Smith//Approval?
>
>     http://wiki.electorama.com/wiki/IBIFA
>     <http://wiki.electorama.com/wiki/IBIFA>
>
>
> First off: IBIFA is similar to MCA, and thus almost a member of this
> class. So I definitely consider it to be a very good system.
>
> Second, I think that DA may be better than IBIFA, not in outcomes, but
> in ease of explanation. This may, in practice, impact outcomes;
> something that's easier to understand may make people marginally more
> likely to vote.
>
> In terms of outcomes: I think that IBIFA does the wrong thing when it
> fails to find a "top-rating" winner. Falling back to "most
> above-bottom" rankings brings the chicken dilemma into the choice of
> whether to rank above bottom. That's why, in DA, in the case where all
> candidates are majority disqualified, the winner is the one with the
> most top ratings, not the most non-disqualified (above-bottom) ratings.
>
> As to Smith//Approval: also a very good method. But it does include
> incentives for non-semi-honest strategy, which rated Bucklin systems
> don't.
>
>
>
>         To me, the toughest realistic election scenario is the chicken
>         dilemma. For instance, consider the following 900-voter scenario
>         300: A>B>>C
>         200: B>>A>C
>         400: C>>B>A
>
>         (where ">>" indicates universal agreement, and ">" at bottom
>         indicates 90% agreement and 10% reversal)
>
>
>     C:  How is this a "chicken dilemma" scenario? In this context, I
>     don't understand what the words "agreement" and "reversal" mean.
>
>
> What I'm saying there is that 200:B>>A>C is actually shorthand for
> 180:B>>A>C, 20:B>>C>A.
>
>
>
>         DA: "Double Approval" or "Disqualify/Approve" voting. Voters
>         can rate each candidate preferred, neutral, or disqualified.
>         (Both preferred and disqualified is also legal and counted,
>         though it's strategically nonsensical.) Winner is the
>         most-preferred among those not majority disqualified. If all
>         candidates are majority-disqualified, winner is simply
>         most-preferred. Any candidate who is majority-disqualified is
>         prohibited from appearing on the ballot for the same office in
>         the following election.
>
>         Lately, I favor DA,
>
>
>     C: Why is rating a candidate both approved and "disqualified"
>     "legal and counted"?
>
>
> Two reasons:
> 1. Even though it doesn't make any sense strategically, it avoids
> throwing away the ballot as spoiled. In general, for most candidates,
> only one of the two kinds of votes is going to matter; and insofar as
> the voter meant either of the marks, it seems more likely that they
> mean the one that matters.
> 2. This makes the system meet the Frohnmayer balance criterion.
>
>     What is the default rating?
>
>
> There is a complex rule for this.
>
> There are three check mark spaces per ballot, for approve, explicit
> neutral, and disqualify. Explicit neutral, when it's in combination
> with another mark or marks, has no meaning. For blank lines, use the
> following rules, in order:
>
> 1. If a voter has used any explicit neutral rankings, any blank
> rankings they include are considered "semi-explicit" disqualify
> ratings. (This is a case where I think intent is pretty clear.)
> 2. If the top two candidates by approvals both have a majority of
> explicit or semi-explicit disqualify ratings, then neutral rankings
> are all counted as implicit disqualify ratings. (This helps prevent
> unintentional "dark horse" wins. It's also a statistical view of
> intent: if voters tend to be negative with their explicit votes, then
> implicit votes should be considered negative too.)
> 3. If neither of the above hold, then blank lines are considered as
> neutral grades. (As above: if voters aren't too negative with explicit
> votes, then I think their intent is most likely not negative with
> implicit ones.)
>
>      The rule regarding "the following election" I consider arbitrary
>     and very undemocratic.
>
>
> This is the case where a candidate wins despite the fact that the
> majority of the electorate put them at bottom. If they are to win a
> second term, they must do so as a write-in.
>
> "NOTA" is a popular proposal. I consider it wrong-headed as part of
> plurality, but I understand the sentiment, and so I think the above is
> a reasonable compromise.
>
>
>     In all these Bucklin/MJ/MCA methods the strategic incentive for
>     the voters to just cast approval-type votes (i.e. only use the top
>     and bottom slots/grades) is in my view
>     far too strong.  The least bad of them is 3-slot MTA (where if
>     more than one candidate exceeds the majority threshold in the
>     second round the winner is the one of those with the
>     most Top Ratings), which is simple and slightly reduces the
>     truncation incentive.  It didn't make your list.
>
>
> That was not intentional. Note that AD is pretty similar, and arguably
> farther in the direction you're favoring.
>
>
>     All them absurdly fail Irrelevant Ballots independence and (unless
>     you have a fetish for strict compliance with Later-no-Help) are
>     completely dominated by IBIFA.
>     The IBIFA winner will always pairwise beat any different winner
>     that any of these methods come up with.
>
>
> Let's take a case where IBIFA and DA disagree.
>
> 40: D>...>A,B
> 35: A>B>D
> 25: B>...>A,D
>
> IBIFA elects A; DA elects B.
>
> Obviously, one could tweak these numbers to try to make one or the
> other system look better or worse. But I think that this scenario is
> more or less a neutral example of its class.
>
> The main question is: are the B voters being honest? If they truly
> feel that A is unacceptable, then I think that B should win. If they
> are using a chicken strategy and hiding their true preference for A
> over D, then A should win.
>
> My feeling is that this kind of situation, where the strategic
> symmetry between the A and B factions is badly broken, is more likely
> to occur through some honest difference rather than through strategy.
> After all, if their sizes are similar, their strategic incentives are
> relatively symmetric; and if the A group is highly dominant, then it's
> likely that A voters would disqualify B, given that even a minority of
> A voters would be enough to do so.
>
> So, while I think that this is a legitimately hard kind of scenario
> and there is some argument for the IBIFA answer, I still feel that DA
> is not only undominated by IBIFA, it's actually better here.
>
>
>     Chris Benham
>
>
>
>
>
>
>
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