[Election-Methods] Determining representativeness of multiwinner methods

[Juho]

On Jun 21, 2008, at 1:09 , Kristofer Munsterhjelm wrote:

> Hello all,
>
> (says the newcomer.)

Welcome.

> First, set that there are n binary issues. Each of the voters then  
> have an issue profile which consists of n booleans.

How do see the role of parties here? Do you use e.g. a binary  
decision between left wing and right wing? Or maybe support or no  
support to party P? Or maybe you don't measure party support at all  
but just separate binary questions.

> However, this presents a problem. How does one aggregate the  
> difference on each issue into a single score? Is a one-percent  
> difference on a single issue better than 1/n percent difference on  
> all issues? One way to solve this is to just settle on an  
> aggregation measure (like root-mean-square) and hope the results  
> can be generalized across;

Any opinions on how to treat different levels of importance of  
different criteria to the voter (and to the candidates)?

> Best of all were the "proper" methods implemented: STV (with  
> Senatorial rules) and QLTD-PR, which uses Woodall's QLTD instead of  
> IRV as its basis: it adds fractional votes until someone gets above  
> the quota, then reweights the voters who contributed to that one,  
> basing the weighting on the candidate's surplus.

How about traditional party list based multi-winner methods? I find  
methods that allow candidates to form a tree like structure (instead  
of the typical flat party structure) where different branches reflect  
different opinions on different key questions interesting from this  
proportionality point of view.


One more observation. Nowadays many methods actually try to meet two  
kind of proportionality requirements, political/ideological  
proportionality (typically based on the party structure) and regional  
proportionality (typically implemented by mandating all to vote at  
their own home district for the local candidates there). These  
scenarios may be out of the scope of the proposed metric because of  
the mandated nature of the regional representation, but regional  
proportionality is one interesting and maybe also measurable  
criterion for proportionality.

Sorry about being "speculation oriented only" instead of making some  
more concrete proposals/claims :-).

Juho






		
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