[EM] "we only get one shot" (Re: RCV Challenge)

[Richard Lung]

Yes, Robert, Condorcet methods are not my specialty.

But 'What is "an exclusion count"?  Or "an election count?"' That is a good question, not at all pedantic. 
Roughly speaking, existing voting methods are election counts helped out by ad hoc exclusion rules. All traditional stv, including Meek, works this way, by getting rid of the candidate least in the way, when the transfers of surplus votes run out. -- "Premature exclusion."
It is also true of party list systems or their hybrids. So, the German MMP is designed to give full party proportional representation, with half the seats going to list candidates. But inconsistently has a 5% threshold defeating that purpose. As a result, the Liberal Democrats, dipping insignificantly in their per centage vote, lost all 40 seats, from one election to the next.

The point is that existing elections are essentially election counts, helped out by ad hoc exclusion rules, missing an exclusion count, in its own right.
The election count, I use (in Binomial STV) is Meek method use of keep values. Meek only uses keep values for candidates elected to a quota or more (because the virtue of Meek method is that it continues to count the later preferences to already elected candidates, requiring the services of a computer program).
Binomial stv also counts the keep values of candidates in deficit of a quota. Why? Because the binomial stv result depends on an exclusion count, as well as an election count.
The difference between election count and exclusion count is simply that an exclusion count is of the voters orders of preference in reverse order. Their respective counts are symmetrical, exactly the same process. Indeed, there is no reason why one persons preference order is not another persons unpreference order. So, there is no logical reason for not having an exclusion count as well as an election count.

The bottom line is that an exclusion count, as well as an election count, makes greater use of the preference information. My old statistics teacher taught us over half a century ago, that the best statistical test is the one that makes most use of the information from the data.

Regards,
Richard Lung.



On 1 Jan 2022, at 6:41 pm, robert bristow-johnson <rbj at audioimagination.com> wrote:



> On 01/01/2022 10:59 AM Richard Lung <voting at ukscientists.com> wrote:
> 
> 
> As far as I know (which isn't far) Condorcet methods are means of cross-checking given methods, rather than a method in their own right.
> 

Uhm, Richard, that's something that, at least some of us are trying to change.  I am trying to make Condorcet a method in Vermont.

In my vocabulary, a "Condorcet method" in it's own right, is any method that is Condorcet-consistent.

And some methods that requires a "Condorcet completion" method (in the vocabulary of https://condorcet.ca/ ) begins with a straight Condorcet method where every pairing of candidates is examined and losers are marked.

> By the way, the point is that an election method should make use of an exclusion count, as well as an election count.

What is "an exclusion count"?  Or "an election count?"

(My pedantry showing again.)

--

r b-j . _ . _ . _ . _ rbj at audioimagination.com

"Imagination is more important than knowledge."

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