[EM] Fwd: Fwd: U/P voting: new name for simple 3-level method.

Tue Sep 13 06:01:40 PDT 2016

Chris is correct. "by most" = "by a majority". Maximum is "*the* most".

Perhaps I should avoid that word, but I was trying to use small words, as
in Randall Munroe's "Thing Explainer".

2016-09-13 6:28 GMT-04:00 C.Benham <cbenham at adam.com.au>:

> Kevin,
>
> I take "downvoted by most" to mean down-voted  by most of the voters,
> meaning down-voted on more than half the ballots.
>
> Your interpretation would be "the most downvoted".
>
> Chris Benham
>
>
>
> On 9/13/2016 2:56 PM, Kevin Venzke wrote:
>
> Hi Jameson,
>
> "Downvoted by most" means the candidate with the single greatest number of
> downvotes? This could be the (voted, unique) majority favorite couldn't it?
>
> How does this violate "irrelevant ballots"? I must be misunderstanding it.
> Does "max amount of upvotes" mean 100% of the voters, or just the greatest
> number of upvotes that occurs?
>
> I do like antiplurality mechanisms.
>
> Kevin
>
>
> ------------------------------
> *De :* Jameson Quinn <jameson.quinn at gmail.com> <jameson.quinn at gmail.com>
> *À :* Kevin Venzke <stepjak at yahoo.fr> <stepjak at yahoo.fr>;
> electionsciencefoundation <electionscience at googlegroups.com>
> <electionscience at googlegroups.com>
> *Cc :* EM <election-methods at lists.electorama.com>
> <election-methods at lists.electorama.com>
> *Envoyé le :* Lundi 12 septembre 2016 20h37
> *Objet :* Re: [EM] Fwd: Fwd: U/P voting: new name for simple 3-level
> method.
>
> Here's a new proposed variant of U/P with a simple default:
>
> Voters may rate each candidate as "unacceptable" (downvote), "preferred"
> (upvote), or "acceptable" (neither). Default is neither.
>
> Any candidate downvoted by most, or with fewer than half the max amount of
> upvotes, is disqualified, unless that would disqualify everyone. The winner
> is the remaining candidate with the most upvotes.
>
> The "fewer than half the max" rule prevents dark-horse winners, without
> resorting to strange defaults. It has no effect on a two-way chicken
> dilemma. Though in theory it could affect an evenly-balanced three-way
> chicken dilemma (in a four-way race), I think there's a negligible chance
> that such a scenario would be so balanced.
>
> I know that Chris doesn't like this method's violation of "irrelevant
> ballots". Myself, I think that no voters are irrelevant; even if they don't
> express an opinion between the two frontrunners, they may have one. (True,
> they may not; but that's not the first assumption I'd make.)
>
> 2016-09-12 20:22 GMT-04:00 Kevin Venzke <stepjak at yahoo.fr>:
>
> Hi Jameson,
>
> I think it is a positive thing that the MTA B/C majority coalition can
> give their sincere preferences (!), while using the strategy they're
> expected to use (i.e. middle slot as tiebreaker given multiple majorities),
> without risk of this strategy backfiring. (Voters can accidentally elect
> the less preferred of B or C, but that is the inescapable chicken dilemma,
> I would say.)
>
> I have some sympathy for your claim that C should not be able to win with
> few top ratings. But that sympathy is not tied to Borda counts, it is based
> on wanting to reduce the truncation incentive for the B voters. This, U/P
> does not really do, because the B>C voters would be taking a large risk
> that they are helping to put C (alone) over the threshold of majority
> approval.
>
> So I don't think either of these ballot sets is likely under U/P, and it
> sounds like you agree with that and think it is good (because it deters a
> pathological ballot set)? Do you have a stance (or at least, see use in
> determining a stance) on how U/P voters in these scenarios should be voting?
>
> Kevin
>
>
> ------------------------------
> *De :* Jameson Quinn <jameson.quinn at gmail.com>
> *À :* EM <election-methods at lists. electorama.com
> <election-methods at lists.electorama.com>>
> *Envoyé le :* Dimanche 11 septembre 2016 1h51
> *Objet :* [EM] Fwd: Fwd: U/P voting: new name for simple 3-level method.
>
>
>
> 2016-09-10 21:26 GMT-04:00 C.Benham <cbenham at adam.com.au>:
>
> On 9/11/2016 5:02 AM, Kevin Venzke wrote:
>
> 43: A
> 24: B>C
> 23: C>B
> 10: D
>
> Under MTA the B and C voters are being completely reasonable: They hope
> for majority approval but can still hope for a win if they
> don't get it.
>
> Strategy is less likely to produce these ballots under U/P because the B
> and C voters are taking a gamble. To get a similar outcome
> they have to vote B=C. Anyone who doesn't is functionally defecting!
>
>
>  C: A very good example!   Assuming MTA and MCA use Top Ratings scores to
> break Approval ties, they both elect the Condorcet winner B.
>
>
> But both could be shifted to C with a single C-only ballot, even if the
> B:C ratio were 46:1 instead of 24:23.
>
>
>
> U/P's under-use of  the middle ratings slot means that it relies more on
> its "majority disqualification" mechanism which seems to make it more
> vulnerable to irrelevant ballots, as in the example.
>
> Under U/P, without the irrelevant D ballots, A and D are disqualified and
> B is the glorious winner. With them, B and C and D are disqualified and
> (without needing
> any others to be disqualified) A wins.
>
> This causes me to reject U/P as clearly worse than MTA and MCA. Of the
> three I (again) rate MTA as the least bad.
>
>
> I think MTA is pretty darn good. I still prefer U/P.
>
> I think that scenarios like the above are fundamentally pathological; any
> possible winner has only minority approval, so that even assuming all
> ballots are semi-honest, any of them could be a true Condorcet loser. Thus,
> I believe that it's more important for a system to try to avoid scenarios
> like the above, than to try to find a perfect winner in such a scenario. In
> fact, in the related scenario:
>
>
> 43: A
> 40: B>C
> 6: C>B
> 1: C
> 10: D
>
> ... I think that a case can be made for either A or B. After all, they'd
> be tied if we try to approximate Score by using truncatable Borda here. But
> no serious case can be made for C or D, even though C wins MTA and MCA.
>
> Anyway, I think U/P does a better job trying to discourage the kind of
> strategy that would lead to a scenario like the above. And part of that is
> the default rule which Chris has criticized.
>
> One possible alternative default rule: ballots alternate between
> defaulting to "acceptable" and to "unacceptable". Each ballot clearly
> states which default it uses, and there is a place on the ballot to
> globally change that default. (I doubt Chris will like this idea, but it is
> at least straightforward, explicit, and easy to describe.)
>
>
> Chris Benham
>
>
>
>
>
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