[EM] Hey guys, look at this...

[Forest Simmons]

Toby,


Thanks for you thoughtful critique!

Do you think  it's worth the extra verbiage of conflating truncation and
bottom rank?

Many times I have conflated them by saying D has "Ballot Bottom Status"
because it outranks no candidate.

But imho leaving the distinction intact is both simpler and totally
harmless ... it just gives voters an optional lever to pull if they want to.

Also in the present context it confers ISDA compliance. Elimination of
Smith dominated candidates does not change the unranked/abstention count of
any remaining candidate, but it may well change the Ballot Bottom Status of
some of them.

One can take the point of view that
the ordinal information is the same on both ballots, but the implicit
approval is different.  The truncation boundary can be considered as an
implicit approval cutoff ... awkward, but better than anything possible
under strict Universal Domain constraints.

With regard to clone dependence ... doesn't it satisfy clone-winner, unlike
any of the other suggestions in this thread?

Doesn't Approval, including implicit approval, satisfy a version of clone
independence? It does under the assumption that true clones are not
interrupted by the virtual approval cutoff candidate (truncation boundary
in this case) any more than they are by other candidates.

Our defeat strength gauge is winning pairwise support plus losing
truncations.

If you replace the defeat winner with a precise clone set ... each member
of the clone set will have the same pairwise support against the loser, so
they will be tied for the strongest victory over the same loser. In
practice, the clone sets are not precise ... but if they were the tie could
easily be broken by applying the method recursively to the tied set ... if
no simpler method existed ... like choosing the tied candidate with the
greatest equal-first count ... another helpful expedient that exists
outside of the strict UD rules.

Another option that makes hardly any difference to the method except to
make its description more wordy, is to gauge defeat strength by winner
implicit approval plus loser implicit disapproval.

Implicit disapproval is already the number of truncations.

And every ballot that pairwise supports the winner over the loser already
contributes to the winner's implicit approval .... so the implicit approval
count will be an increase over the pairwise support.

But is it worth the extra wordiness required ... talking about implicit
approval? We studiously avoided that talk by using "winning votes" a
familiar notion in the context of defeat strength as a proxy for implicit
approval.

Ultimately, if it turns out to make any difference, we should go with the
one that works best .... even if it takes more verbiage.

-Forest


On Mon, Feb 20, 2023, 3:14 AM Toby Pereira <tdp201b at yahoo.co.uk> wrote:

> One thing I'm uncomfortable with is the notion of "unranked" candidates.
> If there are 4 candidates - A, B, C and D - and one ballot has A>B>C>D and
> another just A>B>C, they should be treated as the same. Unranked is just
> (possibly joint) last and I don't see it as having special status.
>
> Toby
>
> On Monday, 20 February 2023 at 01:28:18 GMT, Forest Simmons <
> forest.simmons21 at gmail.com> wrote:
>
>
> I have learned a lot from the "hay guys" thread that spontaneously
> upgraded into this "hey guys" thread.
>
> Colin Champion made some very helpful points and pointers about the
> psychology of what we are involved in. Many similar practical
> considerations contributed by all participants.
>
> Several suggestions have been made about how to complete this sentence:
>
> "Lacking a candidate that defeats every other candidate in pairwise
> head-to-head comparisons, elect the candidate that ..."
>
> I can live with most of those suggestions ... which is neither here nor
> there in the grand scheme of things ... but I hope haven't offended anybody
> or discouraged anybody's contributions to these explorations.
>
> Several people have said, "Why not just ...?"
>
> And I thought, "Why didn't I think of that?"
>
> The most promising idea I am currently thinking along these lines goes
> like this:
>
> Elect the pairwise undefeated champion ... or lacking such a champion,
> elect the winner of the strongest pairwise defeat ... meaning the pairwise
> contest with the greatest sum of winner approval and loser disapproval ...
> winner approval measured by winning votes ... the number of ballots on
> which the winner outranks the loser... loser disapproval measured by loser
> abstentions ... the number of ballots on which the pairwise loser is
> unranked.
>
> So winning votes plus loser abstentions is my proposal for defeat strength
> ... not to be used in Rsnked Pairs ... but just in the first and strongest
> step of RP ... and then only in the absence of a Condorcet Winner.
>
> For now it's just an idea needing an experimental shake down beyond my
> meager manual tests.
>
> But who knows?
>
> -Forest
>
> On Sun, Feb 19, 2023, 10:47 AM Colin Champion <
> colin.champion at routemaster.app> wrote:
>
> I asked Kristofer whether Condorcet+FPTP complied with the Condorcet Loser
> criterion. He replied "probably not" with a sketch proof, and then gave the
> following example.
>
> <quote>
> [preliminary election]
>
> 40: L>C>R
> 42: R>C>L
> 10: C>L>R
>
> R is the Condorcet loser and Plurality winner. (L is the IRV winner.)
>
> Now clone C, the CW:
>
> 40: L>Ca>Cb>Cc>R
> 42: R>Cb>Cc>Ca>L
> 10: Cc>Ca>Cb>L>R
>
> There's no CW, so Plurality elects R, the Condorcet loser. (Incidentally,
> R ties for first in minmax.)
>
> Seems OK. Verified with
> https://web.archive.org/web/20220403135047/http://www.cs.angelo.edu/~rlegrand/rbvote/calc.html.
>
> </quote>
>
> I'd wondered whether Robert didn't have any intellectual commitent to the
> criterion, but had used it in argument against IRV and therefore found his
> options limited.
>
> CJC
>
> On 19/02/2023 17:31, Kristofer Munsterhjelm wrote:
>
> On 2/19/23 16:36, Colin Champion wrote:
>
> "Politicians and the voting public would not accept anything more
> complicated than X" is my own favourite line of argument - but I substitute
> my own value for X(minimax). I know that my judgement is coloured by my
> preferences. There's a surprising degree of dissent over which methods are
> simpler than which, and where the boundary should be drawn. People who deal
> directly with politicians and the voting public can no doubt get closer to
> the truth than people whose interest is predominantly theoretical, but I
> wish there was an authoritative and objective source of information. If
> only some behavioural psychologist was funded to investigate the
> question...
>
> To be finicky, the issue isn't exactly one of simplicity but rather one of
> psychological acceptability, which includes the notions of whether a method
> "makes sense" to the average onlooker, and whether it is seen as conferring
> legitimacy on its winner rather than being an unmotivated piece of jiggery
> pokery.
>
> Notwithstanding all this... you and Robert may well be right.
>
>
> FWIW, I suspect the complexity people are willing to accept depends on
> their trust in the political process in general. For instance, some local
> New Zealand elections use Meek's method, which is complex however you put
> it.[1] And I wouldn't be prepared to explain the pretty messy greedy
> algorithm used to allocate party list top-up seats here (in Norway), but
> people seem to accept it.[2]
>
> I don't think Robert could use minmax because the criterion he's using is
> "if more people prefer X to Y than vice versa, then Y is not elected". That
> seems to imply at least Condorcet loser. I'm not sure, though -- if you're
> particularly critical, you could even say it implies Smith, but I don't
> think Robert had that in mind.
>
> -km
>
> [1] I wonder what the legal language for *that* is... it's basically
> impossible to do by hand.
> [2] IMHO, biproportional apportionment is *much* simpler. I suspect what's
> keeping it from being changed is mostl inertia.
>
>
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