[EM] Fwd: Election-Methods Digest, Vol 236, Issue 18

[Michael Ossipoff]

Experience suggests that natural, sincere, top-cycles are,  & likely will
be, vanishingly rare.

Strategic top-cycles?

The wv Condorcet methods, such as RP(wv) & MinMax(wv), strongly deter
offensive strategy.

As I posted yesterday, that deterrence happens in two ways.

1. They meet Minimal-Defense.
2. Additionally, they’re strongly autodeterent.

If the CW’s preferrers refuse to rank anyone that they don’t like, then
burial to elect someone they don’t like will backfire.

But even without that defensive-truncation, burial is 10 times more likely
to backfire than succeed.

Burial, offensive-strategy won’t happen in wv Condorcet, because it’s
well-deterred, in both of the abo-described ways.



On Sun, Mar 17, 2024 at 23:36 Closed Limelike Curves <
closed.limelike.curves at gmail.com> wrote:

>
>
> *Only if there is a cycle involved.  Either the election was in a cycle in
> the first place or if the burial strategy is to push the election into a
> cycle.If there never ever were any cycles, then Condorcet does not fail.*
>
> This is like saying that if there never were any odd numbers, 3 would be
> an even number. If Condorcet cycles were mathematically impossible, that
> would be great. Sadly, they aren't, so we have to deal with them.
>
> For strategy, the mathematical *possibility* of a cycle--not its actual
> occurrence in a set of results--is what matters, because threatening to
> create a cycle is what forces a Condorcet winner's supporters to vote
> strategically.
>
> The system you're proposing--where we make cycles impossible--is Borda,
> not Condorcet. Saari shows that if you delete every subset of ballots that
> forms a cycle, then elect the Condorcet winner, you get Borda. If Condorcet
> is "strategyproof unless cycles are involved," then Borda is *always*
> strategy proof, because it's got none of them--but clearly it's not, and
> the reason why is because what matters is whether you *could*,
> hypothetically, have a cycle, not whether you actually *do*.
>
> In reality, cycles are always involved. Sometimes it's a real cycle.
> Sometimes it's a theoretical cycle that someone *could* create, and that
> threat gives them leverage.
>
> On Sun, Mar 17, 2024 at 1:06 PM robert bristow-johnson <
> rbj at audioimagination.com> wrote:
>
>>
>>
>> > On 03/16/2024 9:11 PM EDT Closed Limelike Curves <
>> closed.limelike.curves at gmail.com> wrote:
>> >
>> >
>> > > We don't wanna burden voters with any pressure to vote tactically, do
>> we? Why are people (equal.vote (http://equal.vote/), CES) promoting
>> methods that, whenever there are 3 or more candidates, **inherently**
>> forces voters to make tactical consideration of how they're going to vote
>> for their 2nd-favorite candidate?
>> > Every method does this. With 3 candidates all Condorcet methods can
>> encourage burial.
>>
>> Only if there is a cycle involved.  Either the election was in a cycle in
>> the first place or if the burial strategy is to push the election into a
>> cycle.
>>
>> If there never ever were any cycles, then Condorcet does not fail.  No
>> spoiler, no incentive to vote other than sincerely.  If you (the voter)
>> lose, it's because you're in the minority.  If your hated candidate wins,
>> it's because no other candidate is favored by more voters than this hated
>> candidate.
>>
>> > > BTW, I posted at r/EndFPTP a derived scenario that shows how STAR
>> fails to disincentivize tactical voting, even with the head-to-head runoff.
>> https://www.reddit.com/r/EndFPTP/comments/1bbq6hu/heres_a_good_hypothetical_for_how_star_fails/
>> > I don't see how that's a failure. There's two possibilities here:
>> > 1. If the votes are honest, I don't see what the problem is. The three
>> candidates are neck-and-neck and there's not much reason to prefer any.
>>
>> The Center candidate is the Condorcet Winner and STAR *only* compares
>> relative *rankings* in the runoff.  So like IRV, if the Condorcet Winner
>> gets into the final runoff, the Condorcet Winner will always beat anyone
>> else there.
>>
>> The voters supporting Center but who liked Left better than Right would
>> have done better (like get their candidate elected) by burying Left.  (But
>> at least 6 of them, had 4 of them buried Left, they would cause Right to
>> win.)  So, by even by scoring Left at merely 1, they actually betrayed
>> their favorite candidate.
>>
>> The voters supporting Right and who liked Center better than Left (this
>> would be normal) would have done better (like preventing Left from winning)
>> by scoring Center a little higher than they did.  Had 2 or 3 or 6 of them
>> scored Center higher, enough for 6 points, then Left would be defeated.
>> But then they have to betray their favorite candidate and the promise of
>> STAR is that you don't have to do that.  Now, what was hard for the Right
>> voters in Burlington to accept was that their candidate was never going to
>> win in *any* pairwise comparison and that their candidate was the spoiler.
>> But that was actually the case.  Alaska was a little different.  Peltola
>> was always in the lead and there was no "come from behind" victory as
>> occasionally happens with IRV.
>>
>> > 2. If the votes are strategic, this seems like terrible strategy on the
>> part of each group.
>>
>> NO VOTER should have to strategize.  But I explained that if your
>> preference is A>B>C, why without sophisticated consideration of the
>> possibilities it makes perfect sense to score your ballot A:5, B:1, C:0.
>> Makes simple sense, particularly with STAR (and assuming only 3 significant
>> candidates).  The problem is when it's a close 3-way race, then, whether
>> it's STAR or IRV, then tactical voting might serve a voter's political
>> interests better than sincere voting.  We should prevent that burden of
>> tactical voting whenever we can.  (And we can with the ranked ballot as
>> long as there is always a Condorcet Winner.)
>>
>> > Why wouldn't you give the center candidate more than 0 stars?
>>
>> I modeled this after real votes in Burlington 2009.  There were 1289
>> Right voters (outa 3294) that bullet-voted for Right.  There were even 568
>> Left voters (outa 2981) that bullet-voted for Left.  That's what they did.
>>
>> Now, unlike STAR, IRV would not have helped the Center voters with any
>> burying strategy.  The problem with both STAR or IRV is with the Right
>> voters who were told that they can throw their full support behind Right
>> and not get burned by it.  That was clearly not true in Burlington 2009 nor
>> in Alaska 2022 with IRV and I don't think STAR would have done better.
>>
>> --
>>
>> r b-j . _ . _ . _ . _ rbj at audioimagination.com
>>
>> "Imagination is more important than knowledge."
>>
>> .
>> .
>> .
>>
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