[Election-Methods] Matrix voting and cloneproof MMP questions

[Markus Schulze]

Dear Kristofer,

you wrote (6 July 2008):

 > I've been reading about the "decoy list" problem in mixed
 > member proportionality. The strategy exists because
 > the method can't do anything when a party doesn't
 > have any list votes to compensate for constituency
 > disproportionality. Thus, "cloning" (or should it be
 > called splitting?) a party into two parties, one for the
 > constituency candidates, and one for the list, pays off.
 > But is it possible to make a sort of MMP where that
 > strategy doesn't work?
 >
 > That MMP method would have to use some kind of reweighting
 > for those voters who got their way with regards to the
 > constituency members, I think, because if the method
 > just tries to find correlated parties, the party could
 > theoretically execute the strategy by running all the
 > constituency candidates as independents. What kind of
 > reweighting would that be? One idea would be to have a
 > rule that says "those with say x about the constituency
 > vote gets 1-x in the list vote". Then vary x until the
 > point of party proportionality is found. No matter what
 > party someone who makes a difference with regards to the
 > constituency candidate chooses, his vote loses power
 > proportionally, and thus decoy lists wouldn't work.

Wow, that's exactly what I have proposed recently for
an STV-MMP system in Berlin. Please read these papers:

http://m-schulze.webhop.net/schulze4.pdf
http://m-schulze.webhop.net/schulze5.pdf

Read especially page 3 of paper "schulze5.pdf".

Markus Schulze