Dear Kristofer, your argumentation basically is: When some voters rank X higher, then it is not possible that some other candidate Y becomes a member of a solid coalition. My argument basically is: When some voters rank X higher, then it can happen that some other candidate Y who couldn't be elected without violating Droop proportionality can now be elected without violating Droop proportionality. (In example 3 of my paper "On Dummett's 'Quota Borda System'" , X=B and Y=E.) Candidate Y can then kick candidate X out of the winning set. Markus Schulze

I feel compelled to point out that proportionality is not the same as Droop proportionality. Something can fail one particular "brand" of proportionality and still be proportional. On Tuesday, 4 February 2020, 07:48:49 GMT, Markus Schulze <markus.schulze8@gmail.com> wrote: Dear Kristofer, your argumentation basically is: When some voters rank X higher, then it is not possible that some other candidate Y becomes a member of a solid coalition. My argument basically is: When some voters rank X higher, then it can happen that some other candidate Y who couldn't be elected without violating Droop proportionality can now be elected without violating Droop proportionality. (In example 3 of my paper "On Dummett's 'Quota Borda System'" , X=B and Y=E.) Candidate Y can then kick candidate X out of the winning set. Markus Schulze ---- Election-Methods mailing list - see https://electorama.com/em for list info

On 04/02/2020 11.25, Toby Pereira wrote: > I feel compelled to point out that proportionality is not the same as > Droop proportionality. Something can fail one particular "brand" of > proportionality and still be proportional. Yes, you're right :-) What I like about Droop proportionality is that it implies that proportional groups of voters (to some degree) don't have to coordinate to get someone they prefer elected. That is also why something like Warren's "racist"/"color proportionality" doesn't impress me as much, because those proportionality criteria basically say that if everybody who supports a certain party vote all the party members at max and everybody else at min, then the party gets its share. That criterion only tells you what happens if all the voters either coordinate or compromise (give up their chance at deciding who gets to win within the party in order to get the party as a whole to get its share of the seats). Of course, methods that pass DPC might still have a serious coordination or compromising incentive. (The criterion is stronger the more seats there are.) But at least it reduces the need to employ such strategies. Ideally I'd like to have a kind of proportionality that reduces to Webster in the party list case, rather than reducing to LR-Droop, since Webster is much better behaved as a party list method. The only such criteria I've found so far are extraordinarily complex to state, though. Perhaps also something that's to the Smith set what the DPC is to mutual majority. (And obviously, a method passing such a "Webster criterion" would automatically fail the DPC, which is yet another indication of what you say: proportionality isn't the same thing as Droop.)