[EM] STV and single constraints, like gender quotas

[Juho Laatu]

On 27.11.2011, at 12.55, Peter Zbornik wrote:

> Dear all,
> 
> do anyone of you know the best way to incorporate single constraints
> into STV and proportional rankings from STV (see for instance:
> http://www.votingmatters.org.uk/issue9/p5.htm)?
> For instance, the constraint can be that at least 1/3 of the elected
> seats go to candidates of each gender.
> I found some information in the links below, but I wonder if there are
> better or more recent suggestions:
> http://www.votingmatters.org.uk/ISSUE9/P1.HTM
> http://www.votingmatters.org.uk/issue9/p5.htm
> 
> Best regards
> Peter Zborník

I once implemented such a method (brute force and optimizing versions). The implementation was quite straight forward. It just considered results that meet certain criteria better than other results. It included (and started with) proportional raking (planned to elect e.g. chairmen for the group at the same time), and ability to elect certain number of representatives from various (possibly overlapping groups). The implementation fixed the representatives that were elected using proportional ordering (i.e. they were not changed afterwards in the full proportional phase even if there was some more proportional result (resulting iteration could be too complex)).

That was thus a quite straight forward exercise, and I didn't have any other interesting options / criteria in my mind to implement.

One could support at least, exactly or at most certain number of representatives from a certain set. The proportional ranking based group of "chairmen" could also have similar requirements. With multiple groups you could say e.g. that there must be at least 3 blacks, at least 3 women and at least 5 representatives that are either black or women. What other rules would be useful?

Juho