[EM] IRV and Brown vs. Smallwood

[Juho Laatu]

Sorry, fifth line was wrong, should be:

25: Dr>Dm>Rm>Rr
20: Dm>Dr>Rm>Rr
05: Dm>Rm>Dr>Rr
05: Rm>Dm>Rr>Dr
20: Rm>Rr>Dm>Dr
25: Rr>Rm>Dm>Dr

Juho


--- On Thu, 9/4/09, Juho Laatu <juho4880 at yahoo.co.uk> wrote:

> From: Juho Laatu <juho4880 at yahoo.co.uk>
> Subject: Re: [EM] IRV and Brown vs. Smallwood
> To: election-methods at lists.electorama.com
> Date: Thursday, 9 April, 2009, 7:39 PM
> 
> --- On Thu, 9/4/09, Kristofer Munsterhjelm <km-elmet at broadpark.no>
> wrote:
> 
> > Juho Laatu wrote:
> > 
> > > Actually it may be a quite good strategy in
> > > IRV not to rank those favourite candidates
> > > that do not have a chance but to rank only
> > > those candidates that have a chance. This
> > > increases the probability that one's most
> > > favoured candidates with chances of winning
> > > the election are not eliminated too early
> > > (assuming that they might win if they could
> > > stay in the race until the end).
> > 
> > That's also the strategy in Plurality - don't vote
> for
> > those candidates that don't have a chance. But if
> everybody
> > thinks like this, you end up with the "lesser of n
> evils".
> 
> Yes, it is true that if people do not rank
> the lesser candidates they will never grow
> and become major candidates. It may be more
> important for many to try to influence the
> future elections than to try to eliminate
> some small risks in this election. And of
> course in many cases one can vote also for
> the lesser candidates without problems. The
> described strategy is just a safe bet that
> eliminates risks in these elections.
> 
> (Psychological factors are an important
> topic that should be covered too.)
> 
> > One of the points of ranked voting is that you don't
> have to
> > do that - you can vote X > Y > Z so you say "I
> like X,
> > but if I can't have X, I'd have Y before Z".
> 
> It seems that in IRV it is the safest
> strategy not to rank the weak candidates
> (if one only aims at winning this election
> in question), but not a necessary strategy
> for all situations to guarantee an optimal
> vote.
> 
> >    If this ability
> > is compromised by that voting for unpopular
> candidates
> > dilutes the vote so much one should rather not, then
> why
> > have ranked voting in the first place?
> 
> Words "so much" are important. Polls are
> inaccurate, people do believe in the
> chances of their favourites, there will be
> changes in support, there is a need to
> show support to the "so far unpopular"
> candidates, and the risks involved in this
> strategy may be small. As a result I don't
> think people should and people will apply
> this strategy generally in IRV elections.
> 
> There are however cases where the risks
> are very real. The original example was
> one. Here is another with moderate and
> radical Democrats and Republicans.
> 
> Approximate support:
> 25: Dr>Dm>Rm>Rr
> 20: Dm>Dr>Rm>Rr
> 05: Dm>Rm>Dr>Rr
> 05: Rm>Dm>Rr>Dr
> 05: Rm>Rr>Dm>Dr
> 25: Rr>Rm>Dm>Dr
> 
> In this example all four candidates have
> the risk of being eliminated early. If Dm
> or Rm will be eliminated first then the
> other party is likely to win. It makes
> sense to the Dr and Rr supporters not to
> rank their favourite first (although they
> are about as popular within the party as
> the other moderate candidate).
> 
> (From this point of view Condorcet methods
> allow the voters to use more sincere
> rankings than IRV.)
> 
> Juho
> 
> 
> 
> 
> 
> 
>       
> 
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