[EM] Why is wikipedia so biased pro-IRV?

[Kevin Venzke]

Hi Bob,

--- En date de : Jeu 24.2.11, Bob Crossley <bobc1ethelred at btinternet.com> a écrit :
The problem here in he UK is that in many seats we 
do have 3 big parties, and in Scotland and Wales, where there are nationalist 
parties included also, there are sometimes 4. (Northern Ireland has even 
more!) In these cases not voting tactically under AV may have the reverse effect 
to the voters intention. 
 
Faced with examples of instances where AV can fall 
prey to voter strategy, the contention of the more thoughtful members of 
the Yes campaign is that, tactical voting may theoretically be possible under 
AV, but only in very rare circumstances, or that AV makes it so difficult 
to vote tactically that in practice no-one will bother. These are difficult 
claims to counter by example alone.
 
There is a bit of research supporting that 
view which is quoted in the Wikipedia piece "John J. Bartholdi III, James B. 
Orlin (1991) "Single transferable vote resists strategic 
voting,"" I can't say my understanding of it 
is all that great, but it seems to be based on computer modelling of elections 
to find out how often tactical voting can make a difference. My questions are, I 
suppose, how good is this research? Is there other research with computer models 
that contradicts this result? How well can we quantify the 
differences?
 I don't think IRV opponents will criticize that IRV is vulnerable to strategic voting. It's more likely that they will suggest that the characteristics that make IRV resistant to strategy, also can make its results displeasing even when no one uses strategy. I believe James Green-Armytage's recent models suggest that this can produce a nomination disincentive. (Compare FPP's treatment of multiple candidates: If people don't trust the method to give a fair and sensible outcome, the voters or nominating forces can reduce the number of candidates to confuse the method less.)

Or else IRV opponents can criticize non-monotonicity or other things. But, I don't usually see people argue that non-monotonicity will be exploited by strategic voters.

Kevin



      
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