[EM] Preferential voting system where a candidate may win multiple seats

[Kristofer Munsterhjelm]

On 07/07/2013 10:27 PM, Juho Laatu wrote:
> On 7.7.2013, at 16.16, Vidar Wahlberg wrote:

>> Alternatively, instead of running Sainte-Laguë in each county, you
>> could run SL on the national result (distributing all 169 seats),
>> something which would produce a representation percentage very
>> close to the actual result, and then distribute the seats to the
>> parties in the different counties (keeping the same amount of seats
>> in each county).

> I think this makes sense if you do not like the leveling seat style
> of building proportionality at national level. The last seats will be
> distributed pretty much in the same way anyway, but in this approach
> all seats are in principle seen as "equal". The algorithm may either
> aim at some ideal allocation, or be a practical algorithm that just
> finds a good enough result.

There's a balance between national proportionality and local 
proportionality. So if we're trying to get national proportionality 
while respecting local proportionality, it would make sense to alter the 
local distribution as little as possible while still getting a 
nationally accurate result. That's what biproportional 
apportionment/representation does.

My other suggestion was to have regional MPs, i.e. hierarchical MMP. But 
this raises the question of where the regional MPs should reside. I 
suppose national MMP systems have to deal with that issue as well: how 
do they do it? Where do top-up seats MPs in say, New Zealand, reside?

There's also a combination of these two, which I think Schulze 
suggested. If I remember correctly, it's basically MMP with overhang 
handled by deweighting party votes, thus fixing the decoy list problem 
in ordinary candidate + party list MMP.

> If we want full proportinality, then proportionality should thus be
> counted at national level. Another reason why national level votes
> should be used to count the number of seats for each party is that
> one should guarantee that it makes sense to vote for the small paries
> also in the smallest counties. If there is no such prcedure or
> leveling seats or some other national level leveling algorithms in
> place, it would not make sense to vote for small parties in the small
> counties. this would reduce the support of the smallest parties
> already before the votes are counted.
>
> This kind of balancing mechanisms will lead to electing a
> representative of the small party at least in some county, or maybe
> in this voter's own county, even if the number of votes would not be
> sufficient to win any of the seats, if seats would be allocated
> independently in each county.

I'd also like to note that if one were to use a method that tends 
towards Condorcet when there are few seats, e.g. my "CPO-SL" 
(Sainte-Laguë) method I described in "A more Condorcet-like party list 
PR method", then the local seats will be even less proportional as a 
whole. This is related to that SNTV can work in multi-member elections, 
but "pick the top N ranked candidates according to a Condorcet method's 
social ordering" would not.

So if one wants to moderate the local councils with a method that tends 
towards Condorcet when there are few seats, then it becomes more 
important still to have a compensating mechanism to bring the local 
results more in line with the national result. Otherwise, the centrists 
would enjoy a great advantage at the cost of national level proportionality.

And yes, when one adjusts local outcomes to get greater national 
proportionality, that means that someone who "shouldn't" have won on the 
local level nevertheless does win. Hopefully the difference won't be as 
great as to make the voters complain! Perhaps this is part of the point 
of leveling seats: they start off not being owned by anyone, so giving 
them out to party members may not seem as much a way of overruling the 
local result as if one started with all seats filled and *then* adjusted.