[Slightly OT] Re: Voting (was Re: PEP 318

Joe Mason joe at notcharles.ca
Wed Mar 24 14:33:52 CET 2004


In article <1060m0593q1uo0d at news.supernews.com>, John Roth wrote:
> I'd support the "Majority Rules" algorithm. See the article in
> Scientific American (March, 2004 edition) If you run the

There's no free version of the article online, but the authors are given
as Partha Dasgupta and Eric Maskin, and googling on the latter led me to
http://www.sss.ias.edu/papers/papereleven.pdf.

I've only skimmed it, but I'm a little confused by his terms in that
paper.  He first starts, it seems, by defining "plurality/majority rule"
as simply allowing everybody to cast a vote for one candidate, and "a
candidate wins if he or she garners, respectively, a plurality or
majority of all votes cast" - in other words, the obvious way.  But
later on he says, "in true majority rule the winner is the candidate who
beats everyone else in a pairwise comparison", which is Condorcet's
Method.

So I'll assume the "Majority Rules" algorithm is yet another dumbed-down
name for Pairwise Voting aka Condorcet's Method, and say that I like it,
but there's not much point using it for a yes/no vote.  If you're saying to
let people vote on several alternate syntaxes plus "reject outright" -
perfect.

> Cycles are, of course, a problem with that method; you just
> have to do something else to break the tie. Almost anything will
> do if you filter the ballots to just include the issues/candidates
> involved in the tie.

There's a fair amount of analysis on the best method, actually.  In this
case, "Guido's choice" is probably a good one.  (Normally it's done by
counting the relative magnitude of each pairwise win and things like
that.  I'm not clear on whether the existance of a cycle means everyone
in the cycle is really a tossup or if it's fuzzier.)

Joe



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