[EM] I need an example of Condorcet method being subjected to the spoiler effect if any

[Juho]

Yes, Pareto front is a good way to describe the possibility of  
different methods being best for different needs. It is of course  
difficult to agree what the parameters in this calculation should be  
measured. It may be also difficult even for one person to set the  
parameters. But also use of this type of argumentation in regular  
discussion makes sense. Let's hope people will be more analytical in  
this sense in the future.

Juho


On Jan 23, 2010, at 1:36 PM, Kristofer Munsterhjelm wrote:

> Juho wrote:
>
>> Many of the criteria would be nice to have. One must however  
>> remember that often they have two sides. Winning something in some  
>> area may mean losing something in another area (e.g. the LNH  
>> property of IRV has been discussed widely on this list recently)  
>> especially when trying to fix the last remaining problems of the  
>> Condorcet methods. And if one assumes that strategic voting will  
>> not be meaningful in the planned elections then one should pay  
>> attention also to performance with sincere votes, not only to the  
>> resistance against strategies. Different elections may also have  
>> different requirements, so the question of which one of the methods  
>> is best may depend also on what kind of winner one wants to get  
>> (e.g. in some cases the best winner could be found outside the  
>> Smith set).
>
> That's true. Some of the criteria are mutually exclusive, yet others  
> are not. By picking criteria of "worth", one might build a Pareto  
> front: those methods on the front are those that fulfill as many  
> criteria as possible subject to that some are mutually exclusive.
>
> If we didn't forget notable criteria (and thus exclude from the  
> Pareto front methods that by all means should be there), then the  
> front provides the best methods we can get. It's up to one's  
> judgement which of the criteria count more, i.e. which method on the  
> Pareto front one should pick.
>
> For convenience's sake, I've ignored the problem that criterion  
> compliance might degrade the method's "goodness" when given honest  
> votes, and that we don't know which criteria are mutually exclusive.  
> For the former, we (E-M members) disagree about how to go about  
> measuring how good results a method provides on honest votes, and  
> for the latter, we can still build a Pareto front based on the  
> methods we know so far - but it might be incomplete.