> I suppose at some point it stops being a secret election because the number of voters sharing all attributes becomes too small, or the parliament would get unwieldily large trying to represent every hyperspecific constituency.
I'm not sure about that. Maybe I'm being too optimistic, but I'd like to think such a procedure could be run with a legislature of any fixed size, at the cost of the proportionality being increasingly inexact for smaller demographics. Furthermore, I suspect the representatives from any demographic would be elected partly with votes from other demographics. Anyway, the number of voters would presumably be thousands of times the number of representatives - see https://en.wikipedia.org/wiki/Cube_root_law - so any voting demographic with dedicated representation would at least be thousands of voters.
> I suppose at some point it stops being a secret election because the number of voters sharing all attributes becomes too small, or the parliament would get unwieldily large trying to represent every hyperspecific constituency.
I'm not sure about that. Maybe I'm being too optimistic, but I'd like to think such a procedure could be run with a legislature of any fixed size, at the cost of the proportionality being increasingly inexact for smaller demographics. Furthermore, I suspect the representatives from any demographic would be elected partly with votes from other demographics. Anyway, the number of voters would presumably be thousands of times the number of representatives - see https://en.wikipedia.org/wiki/Cube_root_law - so any voting demographic with dedicated representation would at least be thousands of voters.