[EM] Resume: Proportional multi-winner ranked voting methods - guidelines?

[VoteFair]

 > ...
 > The LCR example is a concrete example that giving the
 > first seat to the CW makes the method fail Droop
 > proportionality.

I do not regard Droop proportionality as an important criteria to meet. 
It is based on looking at each ballot one candidate at a time, right?

Looking at one candidate at a time is what instant-runoff voting does, 
and we know how unfair that can be.

Richard Fobes


On 6/4/2017 1:18 AM, Kristofer Munsterhjelm wrote:
> On 06/04/2017 10:07 AM, Juho Laatu wrote:
>>> On 04 Jun 2017, at 07:55, VoteFair <electionmethods at votefair.org>
>>> wrote:
>>>
>>> Yes, "proportional multi-winner Condorcet" has no clear,
>>> unambiguous meaning beyond the criteria for identifying the winner
>>> of the first seat.
>>
>> Yes, it is not easy to say which methods should fall in the
>> "proportional multi-winner Condorcet" category. I also note that even
>> if it would be a requirement that the first seat shall go to the
>> Condorcet winner, if one exists, it is quite possible that the
>> Condorcet winner would not be elected if there are two seats. (e.g.
>> when there are two big parties, left and right, and one small
>> centrist party with a Condorcet winner)
>
> The LCR example is a concrete example that giving the first seat to the
> CW makes the method fail Droop proportionality. E.g.
>
> 43: L>C>R
> 41: R>C>L
>  6: C>L>R
>
> number of voters = 90, Droop quota for two seats = 30, so both L and R
> should be elected, but C is the CW.
>
> For larger assemblies, it might still be a good idea to give a few of
> the seats to winners chosen by a multiwinner method with few seats, or a
> single-winner method. Doing so would make centrists the kingmakers in a
> kingmaker scenario, rather than minor parties on one wing.
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