[EM] Truncation (was re: Defeat Strength)

[Forest Simmons]

Well written and well argued!

And each additjonal explanation reveals more clues of how to construct an
algorithm embodying these lofty principles!

On Sat, Sep 10, 2022, 2:33 PM Richard Lung <voting at ukscientists.com> wrote:

>
> Conservation of information requires all preferences be counted. That
> includes abstentions from some or none of the preferences, like a carte
> blanche. Counting non-preferences is a logical implication of allowing the
> voters to exclude, as well as elect candidates, because whether blank
> preferences come early or late on the ballot determines the relative
> importance of election or exclusion, in a (binomial) count.
>
> A binomial count ballot looks just like any other preference vote, 1, 2,
> 3, etc, but is a preference (election) count and a reverse preference
> (exclusion) count. An election of 5 out of 10 candidates would more or less
> elect the first 5 prefered candidates, and less or more exclude the next 5
> preferences. Preference 10 would count as much against a candidate as
> preference 1 would count for. But the voter could abstain from either
> preference, or both.
> Abstentions would go towards an unfilled vacancy, giving voters the power
> to leave a seat vacant from a less than satisfactory candidate line-up
>
> The mathematical significance of such a binomial count is that it
> completes a dimension of choice. There could be a second dimension of
> choice, making possible a vector model, notably from physics. Physics
> observes conservation laws, including of information.
>
> Regards,
> Richard Lung.
>
>
>
>
>
> On 10 Sep 2022, at 2:25 pm, James Gilmour <jamesgilmour at f2s.com> wrote:
>
> I think there is a lot of misunderstanding in this discussion under the
> Defeat Strength heading, now Truncation.  I suspect it may arise from a
> confusion of "IRV" with "preferential voting".  IRV = Single Transferable
> Vote applied to a single-winner election (= Alternative Vote in the UK)
> uses preferential voting, but there are several (many?) other ways of
> counting the votes recorded on ballot papers marked with voters'
> preferences.  You could use a Borda count, or a Condorcet count, or several
> different 'social choice' methods.  All have different implications for the
> "meaning" of preferences and the "meaning" of truncation (i.e. where the
> voter has not marked a preference against one or more candidates).
>
> What we are not at liberty to do is to take some aspect of the imputed
> philosophy of these other methods and say that it applies to IRV, or that
> it should apply to IRV.  IRV is IRV, and there is nothing in the Election
> Rules for an IRV count (attached) that says anything about the "meaning" of
> multiple blanks (no preferences against several candidates) other than that
> voter prefers the marked candidates to all and any of the unmarked
> candidates and that voter has no preference AMONG the unmarked candidates.
> If the count proceeds such that the next IRV exclusion has excluded
> (eliminated) all of a voter's marked candidates, the Returning Officer
> declares that ballot paper 'non-transferable' and that voter takes no
> further part in deciding the outcome of the election.
>
> James Gilmour
>
>
> > -----Original Message-----
> > From: Election-Methods [mailto:
> election-methods-bounces at lists.electorama.com] On Behalf Of Kristofer
> Munsterhjelm
> > Sent: 10 September 2022 10:30
> > To: Colin Champion <colin.champion at routemaster.app>;
> election-methods at lists.electorama.com
> > Subject: Re: [EM] Trunaction (was re: Defeat Strength)
> >
> >> On 9/10/22 10:48, Colin Champion wrote:
> >>> On 09/09/2022 10:31, Kristofer Munsterhjelm wrote:
> >>>
> >>> For truncation in particular, I think equal last means that unranked
> >>> candidates provides information to the method that the voter desired
> >>> those candidates to be considered worse than everybody else, while "I
> >>> don't know" indicates that the voting method shouldn't care at all.
> >>>
> >> I don t agree with Kristofer's statement.
> >
> > I'm not taking a position, I'm just saying that that's what the "equal
> last" interpretation implies, and contrasting that to an interpretation
> where unranked means no opinion (kitten duel example).
> >
> > I'm not entirely sure which I personally think is the better
> first-principles interpretation. Practically speaking, I think Forest is
> right when he says:
> >
> >> As I understand it, the custom of treating truncation/abstention the
> >> same as equal last rank is a practical expedient to ward off dark
> >> horse upsets.
> >
> > That is, counting unknowns as ranked below everybody else is a way to
> prevent a completely unknown candidate from winning, similar to the
> convention of filling in unrated candidates as zero in Range. This suggests
> that if honest performance is what we care about, unranked should be
> considered "no opinion".
> >
> > On the other hand, there's something intuitively appealing about the
> Plurality criterion:
> >
> > "If A is ranked first on more ballots than B is ranked at all, then A's
> probability of winning should be no lower than B's",
> >
> > which is about a sort of cold start problem: if the data indicates that
> some people like A, but the data is less clear about B, then that should be
> taken to be in favor of A.
> >
> > If complexity is no issue, there might be a soft quorum[1] analog that
> both satisfies Plurality and doesn't presume too much about the ranking of
> unknowns. But I don't know what it would look like.
> >
> > -km
> >
> > [1] For range voting: https://rangevoting.org/PuzzDLaplace.html
> > ----
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> info
>
> <ERS-Alternative-Vote-Election-Rules.pdf>
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