[EM] Real IRV Election, Disputable Result

Anthony Duff anthony_duff at yahoo.com.au
Tue Mar 21 04:06:50 PST 2006

I, like James, have thought about this.  It is particularly relevant in the common
Australian electorate, where the voting pattern is (with A left, B squeezed
centre, C right, extreme and other random candidates ignored):

45 ABC
45 CBA

Even though with IRV, burying your favourite’s greatest perceived opponent has
little purpose, people do it.  One reason is that your favourite recommends it,
another is that it is psychologically satisfying.  People do this, even though
they can barely decide between A and C.  

If IRV were quietly substituted by a condorcet method, then B type candidates
would be elected.

I don’t think that this would be such a bad thing.  Sure, it would be a shock, as
few seriously considered B before, but these centrist candidates in my opinion
tend not be dangerous extremists.  The other thing to remember is that its only
three years to the next election.  At the next election, B is going to be much
more seriously considered, so the problem will not be a long term problem.

I think it is just an implication of the feature that condorcet may favour the
centrist while IRV punishes the centrist (through the centre-squeeze effect).


--- James Gilmour <jgilmour at globalnet.co.uk> wrote:
> Jan Kok Sent: Monday, March 13, 2006 4:07 AM
> > Yes, I agree that the election rules affect how people vote.  
> > But, unsophisticated IRV supporters are not aware that there 
> > can be incentives to vote insincerely in IRV elections, or 
> > may believe that IRV and Condorcet will always, or almost 
> > always, choose the same winner.  If we can find a 
> > counterexample (even if somewhat flawed because the ballots 
> > were intended to be counted by IRV and not Condorcet), it may 
> > wake up some IRV supporters and get them to at least 
> > question, "If these two methods can get different results, 
> > which method gives the better result?"
> The answer to this question, for most electors, will almost certainly be context
> dependent.  Suppose we have a Condorcet
> winner who is not the IRV winner, because that candidate is placed third in
> first preference votes but is "everyone's
> second choice".  If that CW is only a little way behind the two front-runners
> (35%, 34%, 31%), the CW would probably be
> politically acceptable to most electors.  But if that CW has very little first
> preference support compared to the two
> front-runners (48%, 47%, 5%), I suspect the CW would not be politically
> acceptable to most electors.  I can see merits
> in both IRV and Condorcet, but this is a practical aspect of voting reform that
> very few advocates of Condorcet methods
> have attempted to address.
> James Gilmour

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