[Election-Methods] USING Condorcet

[Kevin Venzke]

Hi Juho,

--- En date de : Mar 1.7.08, Juho <juho4880 at yahoo.co.uk> a écrit :
> De: Juho <juho4880 at yahoo.co.uk>
> > I don't entirely agree. I would rank below my
> strategically-determined
> > approval cutoff (if I suppose the same election could
> be held also  
> > under
> > Approval), but I wouldn't rank that much lower,
> and I don't think  
> > other
> > voters should either.
> >
> > Two reasons for this.
> >
> > 1. If you rank everybody and are predictably sincere,
> burial strategy
> > by other voters is more likely to succeed against you.
> People who  
> > would
> > use this strategy need to have doubt about what
> you're going to do.
> > Truncating at the (strategically determined) approval
> cutoff is  
> > good at
> > this: The main effect is that voters don't rank
> all the frontrunners,
> > and burial strategy works basically by assuming one
> frontrunner will
> > get support from another.
> 
> Also heavy truncation is dangerous since that could lead
> even to  
> extensive bullet style voting (and all the benefits of
> Condorcet  
> would be lost).

I don't suggest truncating any higher than the approval cutoff. It should
be safe to truncate somewhat lower than that.

Anyway, whether truncation is a danger to the quality of the results of
the method is quite a different question from whether truncation is a
danger to a specific voter. I think a voter would hardly ever be harmed
by truncating where I suggest (you're withholding support from options
that you shouldn't need unless your information is bad), while they help
(over time) to create a deterrent to burial.

> I also think that the probability of successful strategic
> voting in  
> large public elections is very small in Condorcet.

It doesn't have to be successful. Backfiring strategy is a problem too. A
given voter simply being able to imagine how the strategy could work is a
problem.

If everyone is giving full rankings I think the latter is too easy. Don't 
worry about the Wikipedia election, just take a simple scenario with two 
frontrunners and a third, weak, undesirable niche candidate. If I think 
everyone will give full rankings, then the only reason for me to not use 
burial against the worse frontrunner is the possibility that his 
supporters will be using this strategy against my candidate.

I should not be able to contemplate such a strategy just because of the 
presence of a third, unviable candidate!

In such a scenario, ranking all the alternatives would and should 
accomplish nothing (unless you support the third candidate). The only 
reason to ask these voters to do that is that it would be nice if we could 
say it worked. As strategy advice in this scenario I think it is poor.

Kevin Venzke



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