[EM] book recommendation
John B. Hodges
jbhodges at usit.net
Thu Jul 3 14:05:06 PDT 2003
Greetings- I am still "educating myself" about all these issues. I
asked for book recommendations and got websites instead, which is OK
but I find that websites are shallower than books, almost by
necessity since as a practical matter they are much shorter. At any
rate, I have found exactly the sort of book I was looking for, and
thought I would mention it.
MAKING MULTICANDIDATE ELECTIONS MORE DEMOCRATIC, by Samuel Merrill
III, Princeton University Press, 1988, our library has it catalogued
at JF 1001 M47 1988 (there were many other books in this general
subject area at JF 1001).
Merill is investigating (only) the question of single-seat elections
with more than two candidates. He looks at primarily at seven
systems: plurality, top-two runoff, IRV (Hare), IRV (Coombs),
Approval, Borda Count, and Black's Condorcet Completion method
(Condorcet winner if one exists, otherwise Borda.) In the Preface,
Merrill writes: "My inquiry focuses on the performance of these and
other voting procedures with regard to criteria involving the
legitimacy of the outcome, the tendency of the procedures to choose
centrists or to select candidates of high intensity of support, the
opportunities for manipulation of the outcome, and the stability of
the political system. Since all systems violate one or more of these
criteria under some circumstances, the practical constitutional
problem is to assess for different voting procedures the extent of
these violations and their political implications."
In other words, no system is perfect, so we have to get some measure
of how well each proposed system performs in practice. For example,
it has been proved that every system that allows more than two
candidates will be vulnerable to manipulation, by individual voters
or coalitions, at least some of the time. How easy is it, how often?
He uses computer simulations, "Monte Carlo" methods under varying
assumptions, to get a measure. Likewise with "condorcet efficiency",
how often does a method select the Condorcet winner if one exists?
This list, if I may be so bold, seems to have been established as
part of a drive to defeat one particular reform that seems to be
gaining political momentum, the Instant Runoff method (Hare, or
"Australian" ballot.) The commentary here seems to put down IRV with
extreme predjudice. Merrill finds that IRV-Hare is a major
improvement over Plurality on all measures. Fans of the Condorcet
criterion, which is basically a measure of the tendency of the method
to select centrists, should note that IRV seems to do that quite a
bit better than Plurality. Whether IRV is the best method possible is
open to debate; but it ain't all THAT bad. C'mon, people.
Merill's analysis of the effects of strategic or "insincere" voting,
IMHO, eliminates Borda and IRV-Coombs as serious contenders. IRV-Hare
seems resistant to manipulation.
Approval voting gets a thorough look. It is vulnerable to
manipulation, different rules having different effects; in assorted
scenarios it usually but not always ranks better than IRV on
Condorcet efficiency. I haven't yet finished reading those sections,
which get rather technical.
Oddly enough, even Condorcet-completion methods cannot be relied on
to select the Condorcet winner, once you take into account the
incentives for and effects of insincere voting.
That ends my comments on this particular book. Of course to get a
good handle on the subject one must read more than one book. Enough
for today, Caio.
John B. Hodges, jbhodges@ @usit.net
The two-party system is obsolete and dysfunctional.
Better forms of democracy: www.fairvote.org
REAL CHOICES, NEW VOICES, by Douglas J. Amy
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