[Election-Methods] Juho--WV vs Margins

[Juho]

On Jul 26, 2007, at 12:33 , Michael Ossipoff wrote:

> I pointed out on EM
> that, with Margins, sometimes the only outcomes in which a CW is  
> elected at
> Nash equilibrium are ones in which defensive order-reversal is used.
>
> In other words, in some situations, the election of a CW without  
> defensive
> order-reversal has to be a Nash disequilibrium, an unstable outcome.
>
> In contradistinction, with WV Condorcet, and with Approval (and  
> RV), when
> there's a CW, there is always at least one Nash equilibrium in  
> which the CW
> wins without any order-reversal.
>
> But some Margies are die-hards.

Different Condorcet completion methods have different characteristics  
and none of them are without problems. A good argumentation on why  
these described benefits/problems are crucial in practical (large  
scale public) elections would be nice. Stability is something  
positive but elections are typically arranged as one shot events, and  
ranking based methods generally may have preference loops. => Do we  
expect some strategy planning rounds where these properties would be  
needed? In short, a practical example of a situation where the  
methods have problems in real life would help estimating which  
threats/characteristics are needed in real life.

> Juho says that Margins does better when voters are sincere. But  
> I've posted,
> for Juho, examples in which innoncent, nonstrategic truncation can  
> result in
> a violation of majority rule, and create a defensive strategy  
> problem of a
> magnitude that doesn't happen in WV.

Does that mean that there are examples where margins have problems  
but you don't deny that margins generally elects better candidates  
with sincere votes than winning votes does :-)? I btw assume that  
here "innoncent, nonstrategic truncation" means that there is some  
deviation from the sincere opinion of the voter.

I gave some links to cases where winning votes have problems. There  
are some where margins have more problems. Sorry but so far I haven't  
found the winning vote benefits important enough to justify taking in  
its problems. In case of a tie in performance with strategic votes  
I'd favour margins because of its more natural choices with sincere  
votes. I don't think the differences are really fatal since in most  
regular elections the differences between the methods may not be very  
big. I don't have any new additional arguments right now but the  
interested readers can find lots of discussion in the EM archives (I  
already gave some links to cover the margins side too).

Juho




		
___________________________________________________________ 
Now you can scan emails quickly with a reading pane. Get the new Yahoo! Mail. http://uk.docs.yahoo.com/nowyoucan.html