Brian Olson wrote:
http://bolson.org/voting/sim_one_seat/20090810/
I think a few of these plots show Single Transferrable Vote behaving
badly in the same ways IRV does, with discontinuities and irregular
solution spaces.
I also ran Condorcet and IRNR using combinatoric expansion. Combinatoric
variants of single winner election methods adapt to multiwinner
situations by enumerating all possible winning sets of the available
choices and using a simulated voter's preferences on the choices in each
set to determine a preference for each winner-set. Voting on the
n-choose-k preferences for winner-sets then procedes as for a
single-winner election.
How does the combinatorial expansion work? The way you describe it, it
seems like it's general purpose - that you could combine it with any
single-winner method.
Do you have the source for this program, as well?
I think based on this I'm going to have to think more about making
native multiwinner methods. Combinatoric expansion gets pretty expensive
for large numbers of choices or seats to elect. I had been kinda
resigned to STV being the state of the art in multiwinner methods, but
we seriously ought to be able to do better.
You could try implementing my DAC/DSC-based method (see
http://www.mail-archive.com/[email protected]/msg04001.html
) or Quota-Preferential by Quotient (QPQ, see
http://www.votingmatters.org.uk/ISSUE17/I17P1.PDF ), even if the latter
is nonmonotonic (to my knowledge).
It may also be that the construction of the voter preference profiles
(Gaussian centered on a particular point) means that the ideal maps will
look like Condorcet majoritarian elections. If so, they won't help
distinguish proportional methods from disproportional ones, only show
errors like clone problems.
----
Election-Methods mailing list - see http://electorama.com/em for list info
