[EM] Effect of Approval on candidate behavior

[Rob Lanphier]

Hi all,

As I've mentioned before, there was a very interesting hypothesis made in
Dr. William Riker's article regarding Duverger's law [1].  In it, he asks
what effects the election system has on the behavior of the candidates,
rather than on the voters.

Does anyone know whether anyone has studied this, and has figured out any
way to quantify this?

Without the data, here's my unsubstantiated hunch.  If I were to place
election methods on a two dimensional spectrum, here's what I suspect
candidates would aim:

	     +          FG/IRV  C/B  FG/IRV                        
Strong	     |      FP                       FP           
Leader	     |                                        
	     |                                        
	     |                                        
	     |                                        
	     |                                        
	     |                                        
	     |                  App                     
	     |                                        
Compromising |                                        
      Weasel |                                        
	     +-------------------+-------------------+
              Left            Centrist          Right
              Wing                               Wing
              
Key: C/B=Condorcet or Borda
     App=Approval
     FG=First-past-the-post/General election
     IRV=Instant Runoff
     FP=First-past-the-post/Primary

My hypothesis is that most voting systems at least give canidates pretty
good incentives to be strong leaders, rather than compromising weasels.
You'll note that I make a distinction between "FG" and "FP", as I think
that first-past-the-post (FPTP) systems lead candidates to have different
behavior between the primary and the general election.

However, Approval voting, it seems to me, leads to centrist weasels. 
Basically, it's the "don't offend anyone" voting method, because that's
how I think candidates will win elections.  It seems that when talking
about electing leaders, anyone who actually gets things done is more
susceptable to criticism than a do-nothing. 

That's why I'm worried about the support for Approval on this list from
Condorcet advocates.  It seems that Approval has been deemed "almost as
good", based on mathematical properties having everything to do with voter
behavior, and nothing to do with candidate behavior.

Perhaps looking at it another way, it can be spun as purely a voter
behavior problem.  Approval is almost as good at finding the center of the
spectrum if the spectrum is one dimensional, but I worry that it fails the
two dimension test.

At any rate, this is all based on a lot of intuition, and I'll be the
first to admit that there's probably something I'm not thinking of.
However, I'm really having a hard time agreeing that Approval is a good
substitute for Condorcet.

Rob

[1]  William H. Riker, The Two-party System and Duverger's Law: An
Essay on the History of Political Science American Political Science
Review, 76  (December, 1982), pp. 753-766.
http://www.jstor.org/cgi-bin/jstor/printpage/00030554/di961007/96p0002q/0.pdf
(This link is only accessible on universities with JSTOR access) 

----
Rob Lanphier
robla at eskimo.com
http://www.eskimo.com/~robla