On Thu, May 3, 2012 at 11:25 PM, Aaron Hamlin <aaronham...@gmail.com> wrote:
> Question: Is it possible for a voting system to pass both Favorite Betrayal
> AND Later No Harm criteria?
> I think this is an important question for purposes of rhetoric.
Minimax (Pairwise Opposition) passes both (but unlike most minimax
methods, fails Condorcet).
On Friday, May 4, 2012 9:54:27 AM UTC-7, Dale Sheldon-Hess wrote:
> Minimax (Pairwise Opposition) passes both
But *only* with rank equalities permitted. See Wikipedia:
When the *pairwise opposition* variant is used, Minimax also does not satisfy the Condorcet criterion<https://en.wikipedia.org/wiki/Condorcet_criterion>. However, when equal-ranking is permitted, there is never an incentive to put one's first-choice candidate below another one on one's ranking. It also satisfies the Later-no-harm<https://en.wikipedia.org/wiki/Later-no-harm> criterion, which means that by listing additional, lower preferences in one's ranking, one cannot cause a preferred candidate to lose.
On Friday, May 4, 2012 12:25:49 AM UTC-7, Aaron Hamlin wrote:
> I think this is an important question for purposes of rhetoric.
I know where you were headed with this, but you can still point out that basically every sensible voting method fails one or the other.
But I go even further and argue that satisfying Later-no-harm is actually a *bad* thing, because it forces a system to ignore an arbitrarily large increase in support for Y vs. X, among an arbitrarily large number of voters — so long as those voters still prefer X to Y (even by the tiniest amount).
Would other methods originally designed to be Condorcet (e.g. Schulze)
pass these if pairwise opposition was used intstead of e.g. winning
votes (or margins in other cases)?
On May 4, 5:54 pm, Dale Sheldon-Hess <d...@sheldon-hess.org> wrote:
> On Thu, May 3, 2012 at 11:25 PM, Aaron Hamlin <aaronham...@gmail.com> wrote:
> > Question: Is it possible for a voting system to pass both Favorite Betrayal
> > AND Later No Harm criteria?
> > I think this is an important question for purposes of rhetoric.
> Minimax (Pairwise Opposition) passes both (but unlike most minimax
> methods, fails Condorcet).
> Would other methods originally designed to be Condorcet (e.g. Schulze)
> pass these if pairwise opposition was used intstead of e.g. winning
> votes (or margins in other cases)?
> On May 4, 5:54 pm, Dale Sheldon-Hess <d...@sheldon-hess.org> wrote:
> > On Thu, May 3, 2012 at 11:25 PM, Aaron Hamlin <aaronham...@gmail.com>
> wrote:
> > > Question: Is it possible for a voting system to pass both Favorite
> Betrayal
> > > AND Later No Harm criteria?
> > > I think this is an important question for purposes of rhetoric.
> > Minimax (Pairwise Opposition) passes both (but unlike most minimax
> > methods, fails Condorcet).
> > Would other methods originally designed to be Condorcet (e.g. Schulze)
> > pass these if pairwise opposition was used intstead of e.g. winning
> > votes (or margins in other cases)?
> > On May 4, 5:54 pm, Dale Sheldon-Hess <d...@sheldon-hess.org> wrote:
> > > On Thu, May 3, 2012 at 11:25 PM, Aaron Hamlin <aaronham...@gmail.com>
> > wrote:
> > > > Question: Is it possible for a voting system to pass both Favorite
> > Betrayal
> > > > AND Later No Harm criteria?
> > > > I think this is an important question for purposes of rhetoric.
> > > Minimax (Pairwise Opposition) passes both (but unlike most minimax
> > > methods, fails Condorcet).
On Sun, May 20, 2012 at 7:31 AM, Toby Pereira <tdp2...@yahoo.co.uk> wrote:
> So minimax with pairwise opposition is the only system that satisfies
> both criteria? What strategy would be optimal with this system?
That's a good question, but not one with an easy answer.
I think this whole discussion has only served to convince me that, as
nice as FBC is from a voter's perspective, passing IIA is where it's
really at.
I'm just trying to work out what passing favourite betrayal and later
no harm allows a voter to do. I think it only passes if equal ranks
are allowed. So if A is your favourite and B your favoured likely-to-
win candidates, does ranking A=B instead of A>B never causes A to
lose?
On May 21, 6:40 pm, Dale Sheldon-Hess <d...@sheldon-hess.org> wrote:
> On Sun, May 20, 2012 at 7:31 AM, Toby Pereira <tdp2...@yahoo.co.uk> wrote:
> > So minimax with pairwise opposition is the only system that satisfies
> > both criteria? What strategy would be optimal with this system?
> That's a good question, but not one with an easy answer.
> I think this whole discussion has only served to convince me that, as
> nice as FBC is from a voter's perspective, passing IIA is where it's
> really at.
On Fri, May 25, 2012 at 11:15 AM, Toby Pereira <tdp2...@yahoo.co.uk> wrote:
> I'm just trying to work out what passing favourite betrayal and later
> no harm allows a voter to do. I think it only passes if equal ranks
> are allowed. So if A is your favourite and B your favoured likely-to-
> win candidates, does ranking A=B instead of A>B never causes A to
> lose?
I think yes, but also ranking A=B>C instead of A=B will never cause A
or B to lose.
Yes, certainly ranking A=B>C instead of A=B should never cause A or B
to lose in a system that passes later-no-harm. I think this system
only passes favourite betrayal if equal ranks are permitted, which
suggests to me that the optimum strategy is likely to be to top rank
your favourite along with your favourite among the likely winners (in
fact it's beginning to sound like approval strategy).
By ranking A (your favourite) and B (a likely winner) equal, then if
it did cause B to win over A, then this system could still be said to
pass later-no-harm in some technical sense because you aren't actually
ranking B later than A. But then approval voting would also pass and
as far as I understand it's generally regarded as not passing -
http://en.wikipedia.org/wiki/Later-no-harm#Approval_voting.
On May 25, 8:22 pm, Dale Sheldon-Hess <d...@sheldon-hess.org> wrote:
> On Fri, May 25, 2012 at 11:15 AM, Toby Pereira <tdp2...@yahoo.co.uk> wrote:
> > I'm just trying to work out what passing favourite betrayal and later
> > no harm allows a voter to do. I think it only passes if equal ranks
> > are allowed. So if A is your favourite and B your favoured likely-to-
> > win candidates, does ranking A=B instead of A>B never causes A to
> > lose?
> I think yes, but also ranking A=B>C instead of A=B will never cause A
> or B to lose.
