Say we have an organization or government that wants to use a better
type of two-round runoff than top-two Plurality. What kind of
distribution should the candidates for the second round have?
To be a little more specific, and to make the concept a bit easier to
think about, consider a top-n runoff with Approval ballots in both
rounds. Furthermore, to not have to deal with differences in cloning
problems, say that each group has at least n candidates, so you have at
least n centrists, n left-wing candidates, n right-wing candidates and
so on.
Then what candidates should the runoff method pick for the second round?
It could pick according to ordinary Approval. If we consider the
electorate to be centrist, that would lead to n centrists being elected
to the second round. The lack of variety might keep the voters from
bothering to turn up in the second round. On the other hand, because
they're all similar, it might lead to a more detailed discussion of
different shades of centrist policy, thus informing the voters more and
letting them make better choices in the second round.
On the other extreme, the method could pick the candidates for second
round using minmax Approval. This would produce a great variety of
candidates, so the second round decision would probably seem more
meaningful to the voters. On the other hand, because the ideological
positions are so clearly defined and the n candidates would be spread
across the spectrum, it would be easier for say, a right-wing candidate
to say "that guy over there is a leftist; vote for me if you like
capitalism" (or whatnot) instead of discussing the more subtle aspects
of politics.
Between these extremes, we have selection by proportional
representation. For Approval, that would be PAV or one of the
combinatorial methods (biweight, etc). This approach is not as focused
on the candidates everybody agrees are good (as in ordinary Approval)
not on the candidates at least someone thinks is very good (as in minmax
Approval), and thus, basically, is a combination of both.
Which do you think would be best? What kind of discussion would give the
best candidates in the long run -- one of subtleties in centrist policy,
of breadth among a very wide variety of positions, or proportional
representation?
I suppose TTR lies somewhere around the PR choice, selecting candidates
by SNTV. But SNTV is not a good proportional representation method, n=2
doesn't give a great variety of candidates anyway, and TTR may be set up
the way it is to fix problems in Plurality, not just to let the voters
get a second look at the most suited candidates.
----
Election-Methods mailing list - see http://electorama.com/em for list info
