Date: Wed, 17 Sep 2003 23:03:19 -0700 (PDT) From: "Alex Small" <[EMAIL PROTECTED]> Subject: [EM] Extremism
It is sometimes asserted in various places (including, occasionally, this forum) that PR promotes extremism and single member districts (SMD) promote moderation. There's no denying that PR would give representation to small extremist factions. But small extremist factions would still have small caucuses while large centrist groups would have large caucuses. (snip) The result of this incumbent protection is that legislative elections are now decided in the party primaries. Party loyalists are of course more extreme than the rest of us. (snip)
If we had PR, and we were liberated from the tyranny of the party loyalists, (snip)
(JBH) Stephen Hill talks about this in FIXING ELECTIONS. But, Whether PR would be better depends on the type of PR. PR of any kind would limit the representation of extremists to their actual percentage of support among the electorate, but any sort of "party list" PR (i.e. the most common kind) will tend to have each party list reflect the party activists. Whether that is a disadvantage under PR is open to debate; perhaps it is a good thing that each party have a clearly defined and distinct position. But assuming that it is bad, then this argument would tend to favor forms of PR that do not depend on parties, and which give advantage to candidates who can attract second-choice votes. STV is well-known and has been used in real elections for awhile. GB 2.3 would also qualify, theoretically.
I've been wondering if the PR aspect of GB 2.3 could be applied to other voting methods besides Generalized Bucklin. Something along these lines:
1. collect the ballots.
2. count the ballots, calculate the Droop Quota.
3. Use (insert your favorite single-winner method here) to pick a winning candidate.
4. Do any seats remain to be filled? If not, you are finished.
5. identify the DQ strongest supporters of that candidate. Delete their ballots. (If your criteria for measuring strength of support gives you a set of equally-strong supporters larger than the DQ, then multiply all such ballots by the fraction (#supporting-ballots minus DQ)/DQ. )
6. go to 2. (repeating 2 is necessary because of the possibility that some ballots may be exhausted, so the DQ will change.)
Sometime I may get around to the chore of trying this with Ranked Pairs. But I suspect that the procedure above is flawed by itself, regardless of what single-winner method is used in it. Working through examples with GB 2.2, which would be an example of the above PR method, I found that it sometimes gave the "wrong" results. It seems to be better if a PR method picks all, or at least several, winners simultaneously.
Has anyone tried checking whether Ranked Pairs could do satisfactory PR by filling N seats with the N highest-ranked candidates? I suspect it would not; too much bias toward the center.
-- ---------------------------------- John B. Hodges, jbhodges@ @usit.net Do Justice, Love Mercy, and Be Irreverent. ---- Election-methods mailing list - see http://electorama.com/em for list info
