[Election-Methods] Determining representativeness of multiwinner methods

[Kristofer Munsterhjelm]

Juho wrote:
> On Jun 24, 2008, at 0:34 , Kristofer Munsterhjelm wrote:
> 
>> What do you mean by "methods that allow candidates to form a
>> tree like structure"? Something like delegable proxy, or just
>> preference ballots with parties instead of candidates? Or
>> nontraditional nested democracy (groups elect members to an
>> assembly - groups of assemblies elect members to a second-
>> level assembly, onwards up to global issues)?
> 
> I was thinking about the traditional party structure and proportional 
> methods and how they may provide quite exact proportionality between 
> parties but how they can not provide proportionality in any more 
> detailed level. In this set-up it is possible to split one party e.g. to 
> the green wing and others, and then the green wing could consist of 
> radical and moderate greens. A vote to the radical greens (of this 
> party) would be a vote also to the green wing in general and to the 
> party in general.
> 
> The point was that now you could have even the binary decisions 
> "stacked" in the party hierarchy (at least if the tree would be a binary 
> tree). In this model it would also make a difference if you vote the 
> green wing of the socialists or the socialist wing of the greens (order 
> of priority).

If the parties as well as their respective divisions (and subdivisions) 
were to produce their own party lists, that would be a whole lot of lists.
One might be able to get the effect without all the lists by having a 
candidate ranking option, similar to "voting above the line" but with 
candidates instead of parties. A voter voting for a radical green 
submits an approval or plurality-type ballot for the radical green, and 
the system substitutes this with "RadicalGreen1(Party F) > 
RadicalGreen2(Party F) > ModerateGreen1 > .... > Mainstream1(Party F) > 
... > Whoever(Party X) > SomeoneElse(Party Y)". That is, the nesting is 
done implicitly in the ranking substitution, after which the ranked 
votes are input into your favorite multiwinner method.

The substituted ranks (candidate-individual automatic how-to-vote cards) 
would nest outwards, from the small wings to the increasingly larger 
ones within the party itself, then on to other parties in preference. In 
a sense, they are "lists" of their own, and so the problem isn't 
completely avoided.

In an ideal world, one could argue that if voters assume a candidate is 
acceptable (if not, why would they vote for them?) then they could also 
reasonably assume that the candidate's premade substitute rank can be 
trusted. But in reality one may pick a candidate not because he's 
absolutely trustworthy, but because the others are worse, and the method 
in any case amplifies central power (like closed list PR does, and for 
pretty much the same reason).