2017 update to the SPI voting algorithm for Board elections [and 1 more messages]
Dimitri John Ledkov
xnox at spi-inc.org
Tue Feb 28 15:33:18 UTC 2017
On 27 February 2017 at 22:30, Barak A. Pearlmutter <bap at debian.org> wrote:
> I am very happy to see SPI adopt a voting system designed for
> proportional representation.
> However I do feel obligated to correct a simple incorrect statement,
> namely that STV, a proportional representation system built upon IRV,
> is in some sense best-of-breed. STV in fact exhibits a variety of very
> serious pathologies, not just in theory but in actual practice. Even
> IRV itself exhibits some serious problems, including most troublingly
> non-monotonicity---meaning that under some not-unusual circumstances
> changing a ballot to rank a particular candidate *higher* can cause
> the candidate to go from winning to losing. STV necessarily inherits
> these pathologies.
> Although poorly formatted, the following case study of an actual
> election, the 2009 Burlington Vermont Mayoral election, shows that the
> IRV system actually used exhibited about the worst imaginable
> pathology: of the three major candidates, it elected the one who lost
> head-to-head to each of the other two according to the ballots cast.
> Details: http://rangevoting.org/Burlington.html
> Burlington subsequently changed its election system away from IRV.
> Similar pathologies apparently happened in the IRV 2006 Peru
> presidential election and the IRV 1970 Chile presidential election.
> Using the Debian leader election data 2001-2005, in one of those five
> elections IRV would have given a different winner than the Condorcet
> method actually used, even though in all cases the Condorcet winner
> beat all other candidates head-to-head. See
> http://rangevoting.org/Debian2003.html for details. In another one of
> the elections there were a variety of IRV pathologies actually
> exhibited. The most interesting of these to me is that there were two
> ballots each of which had the property that, had IRV been used,
> removing that ballot, which prefers A to B, would have changed the
> winner from B to A.
> I don't have a dog in this fight. I'm just interested in the math and
> in Bayesian methods. These have convinced me that Reweighted Range
> Voting (RRV, http://rangevoting.org/RRV.html) and Asset Voting are the
> best proportional representation voting systems currently known. And
> that the problems with STV are not merely academic but occur
> frequently in real elections. Asset Voting does not seem practical for
> SPI---although it would be pretty fun. STV (and even IRV) do not come
> off very well in any of the careful neutral analyses I've seen.
My personal impression about this is that irrespective of the voting
system used, there will always be anomalies. And the proposal here is
to change one set of quirks for another.
Note that unlike the DPL / Mayoral elections we are striving to elect
3 directors for a three-year term every year, such that the board has
continuity and is thus staggered.
So far I have also been impressed with the quality of candidates, and
(semi-jokingly), I could even be in favor of using urandom() algorithm
to pick winners.
If the proposed algorithm picks an underdog as one of the directors I
would be fine with that, since that adds entropy to the election
results which imho is exciting and fun =)
ps. I might actually use urandom() next time I need to cast a ballot
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