[EM] Wikipedia

[James Green-Armytage]

Eric Gorr <eric at ericgorr.net> writes:
>What I was most interested in was his declaration that Condorcet is 
>not a one-person, one-vote system.
>Thoughts?

	So far, I don't fully understand why is IRV a "single vote method", Borda
count a "multiple vote method", and Condorcet a "pairwise vote method",
when they are all ranked ballot single-winner systems that can be
conducted in a single round. There's probably some justification for it,
but at first look I find it to be more confusing than helpful.

	Did Tom actually change the Wikipedia page? I didn't find the changed
page when I looked. I hope that he didn't change it.

	There are plenty of different ways to taxonomize voting systems. Perhaps
the most fully effective way would be on some sort of a multi-dimensional
grid, each dimension for a specific characteristic. That is, single winner
or multiple-winner, one round or more than one round of voting, ranked
ballots limited-rank ballots or rated ballots, and so on. But of course
it's problematic to put something like that in writing, so you have to
come up with a simpler and more linear taxonomy, which involves a choice
as to which characteristics are considered first.

	I think that the single-winner vs. multiple winner distinction is a good
one to make first.

	Then I'd probably go to the ballot type. There's 
1. a choose-one ballot (plurality and runoff), 
3. a ranked ballot (IRV, Condorcet... permissibility of equal rankings
should probably not be considered until later since many ranked methods
have versions that do and do not allow them...), 
4. a rated ballot (cardinal ratings, etc.), 
4. a limited ratings ballot (approval, or any system where the possible
number of "scores" for a candidate is less than the number of candidates)
5. a combined ballot (a method combining different kinds of ballots in a
single election), and then maybe 
6. a miscellaneous category

	Hmmm... I guess that you could call approval either a limited-ranking
ballot (one with only two possible rankings), or a limited-rating ballot
(one with only two possible ratings, 1 and 0). I don't really have a
strong opinion as to calling it one or the other. I don't even know
exactly what distinguishes a rated ballot from a ranked ballot... Is it
the possibility that in a rated there may be several more available
"places" or "scores" then there are candidates? (e.g. 5 candidates ranked
on a 100 point scale.) Or the idea that the number of available places is
independent of the number of candidates in general? If the latter, then I
guess approval would be more of a limited ratings system.

	Anyway, that's what makes the most sense to me now. In my own voting
survey I don't have it grouped quite like that, actually, but it's
relatively close. Here is the current table of contents for that, which
shows the taxonomy I used. Maybe I should update it a bit at some point?...


I. Single winner voting methods
       A. Non-ranked ballot methods
              1. Plurality
              2. Two round runoff
              3. Approval
       B. Ranked ballot methods
              1. Borda
              2. Instant runoff voting / the alternative vote
              3. Condorcet methods
                     a. Minimax
                     b. Smith set + minimax
                     c. Schwartz set
                     d. Schwartz sequential dropping
                     e. Beatpath
                     f. Ranked Pairs
                     g. Other Condorcet methods
                            i. Raynaud
                            ii. Dodgson
                            iii. Kemeny
                            iv. Condorcet completed by IRV 
                     h. A strategy problem
       C. Miscellaneous single winner methods
              1. Candidate withdrawal option IRV
              2. Lowest two elimination runoff
              3. Coombs
              4. Bucklin
              5. Cardinal ratings

II. Multiple winner voting methods
       A. Non-proportional methods
              1. At large plurality / block voting
              2. Other non-proportional systems
       B. Semi-proportional methods
              1. Cumulative voting
              2. Limited voting and single non-transferable vote
       C. Proportional methods
              1. Party list
                     a. Open and closed lists
                     b. Allocation formulas
                            i. Largest remainder
                                   aa. Hare quota
                                   bb. Droop quota
                                   cc. Newland-Britton quota
                            ii. Highest average
                                   aa. Saint-Lagüe divisors
                                   bb. D’Hondt divisors
                     c. Thresholds
              2. Single transferable vote
                     a. Surplus transfer rules
                            i. Random
                            ii. Fractional transfer
                            iii. Meek
              3. CPO-STV
       D. Combined systems
              1. Parallel
              2. Mixed member proportional representation
III. Direct democracy systems
       A. Proxy systems