[EM] Test of elimination counts versus proportional counts.
Richard Lung
voting at ukscientists.com
Sun Dec 3 07:52:41 PST 2023
Test of elimination counts versus proportional counts.
The elimination count may be described as the possibility of replacing
one less prefered candidate than another. This is especially the basis
of so-called Instant Run-off Voting, where the idea is that some
candidates may have more general support than another, after the
run-off. This system is also known as the Alternative Vote (AV).
By convention, AV is generally reserved for the single-member
constituency or system case. And the single transferable vote is
confined to multi-member constituency elections. This means that STV is
a broken-backed system, because it does not apply to all constituency
systems, single-member and multi-member constituencies. By the same
token, AV is no more than a special case. It has never gained
multi-member currency, beyond a short lived trial, for instance in
British Columbiain the nineteen fifties. It has its very occasional
reform advocate for a “bottom-up” election system. That is to say for
rank choice in a multi-member elimination count system.
As Enid Lakeman, in How Democracies Vote, pointed out, the lack of a
proportional count means that the overall majority voters may win in not
just a single constituency seat, but in every seat in a multi-member
constituency.
Contrast this by how a proportional count can make the single
transferable vote applicable, not only in multi-member constituencies
but also single-member constituencies. STV, unlike IRV (alias AV), can
be made a consistently proportional count, whereas IRV/AV cannot
maintain a majority count, by elimination methods, in more than a single
seat constituency.
The general rule, to apply beyond the study of election methods, is to
introduce a one-truth condition to any election system.
The worlds existing election systems are two, or more, truth systems. I
won’t attempt to say how many conflicting “truths” the Additional
Members System (alias MMP) stands for. But ad hoc hybrid election
methods are a bad idea, for this reason. (Tho these doubly safe seat
systems may be an inspiration to career politics.)
Given that the elimination count does not produce even a bare overall
majority in multi-member constituencies as well as single-member
constituencies, that leaves the proportional count alternative to
attempt a single-member count as well as a multi-member count.
It is the case of course that there cannot be proportional
representation in single-member constituencies. (Not always appreciated
by politicians, terrified, for their jobs, of any reform in the voting
system.)
It is rightly appreciated, that with a proportional count, the voters
for any candidate who has won votes in surplus of the quota (here, of
one half the voters) cannot have the surplus transferable to the voters
next preferences, because, by definition, there is no other vacant seat
in the constituency.
Nevertheless, a transferable surplus in a single-member constituency is
a measure of that candidates popularity. (It is the “keep value” in Meek
method multi-member elections.)
Now here is the novelty. Use Meek method of surplus transfers in
elections, also as the means of excluding candidates, applied to the
voters reversed preferences. Then, invert the exclusion preferences, so
you have a makeshift second-opinion election. You can legitimately do
this, because one persons preference is another persons reverse
preference. In other words, Meek surplus transfer is as logically
legitimate as an exclusion count as it is as an election count.
Now you have two sets of keep values, election keep values and exclusion
keep values, inverted, to be second opinion election keep values. Hence
their (exclusion count over election count) ratio serves as an average
keep value (actually, the square of their geometric mean).
These average keep values can serve as the election criterion of from
one to many candidates. That is to say this “binomial” count of both
rational election and rational exclusion is consistently applicable to
single member and multi-member constituencies.
There are other considerations, such as the need to count all the
abstentions, to-weigh the relative importance, to the voters, of
electing and excluding candidates, and what to do with any “Schrödinger
candidate” [Forest Simmons] both elected and excluded.
However, STV would be no longer a broken backed system but, for the
first time, a one -truth election system. And this is a criterion that
elimination counts, and official elections in general, fail to meet.
Richard Lung.
.
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