[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.

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

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