[EM] STAR

[Forest Simmons]

It turns out that electing the highest score Landau candidate fails mono
raise. Same thing for Banks, which is why it is non trivial to get
monotonic Landau and Banks efficient methods.

On Mon, Aug 21, 2023, 5:42 AM Toby Pereira <tdp201b at yahoo.co.uk> wrote:

> By the way, if you started with the score winner, would it just be
> Landau//Score?
>
> Toby
>
> On Saturday, 19 August 2023 at 21:37:23 BST, Toby Pereira <
> tdp201b at yahoo.co.uk> wrote:
>
>
> Forest
>
> I'm not sure it would be undiplomatic to start with the score winner. The
> top two run-off in STAR is the second stage to complete the method after
> doing score voting. By saying that it needs further completion is doing
> away with STAR's completion anyway, and to have three stages seems
> unnecessarily unwieldy and more likely to throw out strange results. STAR
> is also not clone independent, so this goes against your stated preference.
> This is just another way to complete the method instead of STAR, so I think
> it makes sense to start with the score winner, rather than the STAR winner.
>
> Toby
>
> On Sunday, 13 August 2023 at 00:12:21 BST, Forest Simmons <
> forest.simmons21 at gmail.com> wrote:
>
>
> That would be simpler, but not as diplomatic.
>
> You could initialize the chain with the winner of anybody's favorite
> method, but ideally it would be a monotone clone independen method.
>
> Pairwise Dominate is another (more descriptive way to say "cover" ...
> which I defined as the opposite of not being Pairwise Dominated.... we want
> our winner to be undominsted pairwise ... which can be easily checked as I
> suggested by the existence of a short return beatpath to any challenger.
>
> On Fri, Aug 11, 2023, 5:19 AM Toby Pereira <tdp201b at yahoo.co.uk> wrote:
>
> Wouldn't it be simpler (and better?) to start with the score winner rather
> than the STAR winner?
>
> What do you mean by pairwise dominate in this context? I presume from the
> context (when you talk about Copeland) it's not the same as pairwise beat.
> Are you talking about covering in the Landau sense?
>
> On Friday, 11 August 2023 at 01:19:30 BST, Forest Simmons <
> forest.simmons21 at gmail.com> wrote:
>
>
> Score Then Automatic Runoff (STAR) elects the pairwise winner between the
> two candidates with the highest score totals.
>
> One of the biggest problems with this method is that there is an
> appreciable likelihood that the winner W will be a candidate that is
> pairwise dominated by some other candidate C, which means that C not only
> scores higher than W on more ballots than not, but if there even exists  a
> beatpath from W back to C, it will take at least three steps.
>
> Most other extant methods have this same defect, but almost all of them
> are hard to fix compared to STAR. This fact makes it easy for a tweaked
> version of STAR to become arguably superior to any of these other methods.
>
> 1. Initialize a set S of candidates with the STAR winner.
> 2. If any candidate pairwise dominates the newest member of S, from among
> such candidates add in to S the one with the highest score.
> 3. Repeat step 2 until the set S cannot be enlarged any further in this
> way.
> 4. Elect the last candidate to be added to the set.
>
> Usually step 2 will be invoked only one or two times if at all ... so this
> is not a big tweak.
>
> With this tweak STAR becomes arguably superior to any method currently in
> use.
>
> The only other method currently in use that always elects pairwise
> undominated candidates is Copeland.  But Copeland suffers from two fatal
> defect that STAR does not have ... Copeland is neither Decisive nor Clone
> Independent.
>
> Will STAR proponents take advantage of this opportunity? ... or will they
> pass it up?
>
> fws
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