Fwd: Fwd: U/P voting: new name for simple 3-level method.
Ok. It took me a little while to conclude that "most" was intended to be the end of that noun phrase. I saw that it had to be, but also wondered whether there was a missing word or something.
This method is sort of like a ratings version of my disqualified plurality method (on a "vote for and against" ballot), which also disqualifies only if there's a full majority. But my method can only elect either the first- or second-place candidate (by "for" votes).
I imagine most voters wouldn't use the middle slot in this method.
Kevin
De : Jameson Quinn <jameson.quinn@gmail.com>
À : C.Benham cbenham@adam.com.au
Cc : Kevin Venzke stepjak@yahoo.fr; EM election-methods@lists.electorama.com
Envoyé le : Mardi 13 septembre 2016 8h01
Objet : Re: [EM] Fwd: Fwd: U/P voting: new name for simple 3-level method.
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@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@gmail.com>
À : Kevin Venzke stepjak@yahoo.fr; electionsciencefoundation <electionscience@googlegroups. com>
Cc : EM <election-methods@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@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@gmail.com>
À : EM <election-methods@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@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 "majoritydisqualification" 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
Election-Methods mailing list - see http://electorama.com/em for list info
Election-Methods mailing list - see http://electorama.com/em for list info
Election-Methods mailing list - see http://electorama.com/em for list info
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7797 / Virus Database: 4649/13003 - Release Date: 09/12/16
Election-Methods mailing list - see http://electorama.com/em for list info
Election-Methods mailing list - see http://electorama.com/em for list info