[EM] Score Voting and Approval Voting not practically substantially different from Plurality?

[Juho Laatu]

On 25.6.2013, at 18.07, Benjamin Grant wrote:

> On Tue, Jun 25, 2013 at 3:00 AM, Juho Laatu <juho.laatu at gmail.com> wrote:
> On 25.6.2013, at 1.06, Kristofer Munsterhjelm wrote:
> 
> > Remember that criterion compliances are absolute. So a method may fail a criterion yet be perfectly acceptable in real elections.
> 
> I just want to support this viewpoint. It is not essential how many criteria a mehod violates. It is more important how bad those violations are, i.e. if the method likely have serious problems or not. The best method might well be a method that violates multiple criteria, but manages to spread the  (unavoidable) problems evenly so that all of them stay insignificant.
> 
> Hmmm.  I think I would like to be more cautious. I think there are different levels of worries:
> Having a criterion fail often in practice is worse than having it fail more rarely in practice.
> Having a criterion fail rarely in practice is worse than having it fail more hypothetically (than actually).
> Having a criterion fail hypothetically is worse than not having it fail at all
Yes, we should carefully analyze the benefits and problems and to find a good balance.
> Now there are some criteria that aren't important to me at all, that I do not value what the try to protect - and those I factor out.  

I think I don't have any criteria that I'd absolutely require. My approach is pragmatic in the sense that since all methods will have some theoretical problems, I just try to make sure that IN PRACTICE the vulnerabilities do not cause us problems. Most criteria aim at something positive, so one should aim at their targets, byt 100% compliance is not a requirement since we need to make compromises anyway in one place or another.

> But in general, I am going to try to be very aware of the nature and prevalence of the unpleasant results that violating criteria can bring.
> 
> In other words, until a particular system's violation of a criteria is clearly demonstrated to me to be insignificant, I shall instead adopt a worst case approach. ;)

It is possible to approach this problem also from the other direction. One could say that in addition to proving that a theoretical vulnerability exists, one must also present a credible scenario where the vulnerability may cause problems in some real life elections. Only after that one can estimate the seriousness of the problem. (This has also to do with the fact that it is often impossible to prove that there will be no harm in any circumstances, but it is quite easy to demonstrate a practical vulnerability by generating a set of imaginary voter opinions and pointing out how the voters could apply some strategy successfully.)

Juho



> 
> -Benn

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20130626/1a2b796b/attachment-0003.htm>