[EM] proportional constraints - help needed

[Richard Fobes]

On 2/13/2013 4:51 AM, Peter Zbornik wrote:
> 2013/2/9 Richard Fobes<ElectionMethods at votefair.org>:
 >> ...
>>> 2013/2/6 Richard Fobes<ElectionMethods at votefair.org>:
>> ...
>> The method consists of running VoteFair _representation_ ranking
>> calculations. ...
>> ...
>> Tentatively the five open-list party positions are assigned to the five
>> candidates who are ranked as most representative -- according to VoteFair
>> _representation_ ranking.
>>
>> These results are proportional.  And they are very resistant to strategic
>> voting.  The details are explained at this web page:
>>
>>      http://www.votefair.org/calculation_details_representation.html
>>
>
> Does VoteFair representation ranking fulfil the criterion, that
> candidate for seat number 2 is elected proportionally to the elected
> candidate at seat 1, ...

Yes.

 > ...
  and candidate for seat number 3 is elected
> proportionally to the elected candidates at seats 1 and 2, etc....

This brings up an important point that I was already thinking of 
bringing up.

There is a difference between proportionality when the number of seats 
is known -- which is what STV is designed for -- and proportionality for 
an open-party list where the number of seats that will be won by the 
party is not known in advance.

In this case (regarding the first three positions), if the first three 
candidates were selected so that each represents one-third of the 
voters, and the Green party wins only two seats, then only two-thirds of 
the voters will be represented.  That is not proportional in the 
legislature, even though the first three party-list positions are 
allocated to be very proportional.

VoteFair representation ranking chooses for the third position the most 
popular person from among the remaining candidates.  This is a fair 
approach for the two-seat win, the three-seat win, and the four-seat win.

At about position # 5 there needs to be some additional calculations. 
This is what I referred to when I said that VoteFair _negotiation_ 
ranking has a method that would be useful starting at about position # 5.

Also note that, as Jameson pointed out in a separate post, in order to 
ensure full proportionality beyond the first few seats -- say if ten or 
more seats might be won -- there has to be some additional information 
from the voters in order to select one or two candidates who represent a 
small minority.

> ... as in
> the top-down method of Otten?

I did not find any information about the "top-down method of Otten."  If 
you send me a link to a place that describes it, then I can answer this 
part of your question.

>> If the tentative results already happen to meet the quota for women, then no
>> adjustments are needed.
>>
>> If there are no women in any of the tentatively assigned five positions,
>> then the two women who are the most popular according to VoteFair
>> _popularity_ ranking are moved into positions # 2 and # 4, and the men are
>> shifted down.
>>
>> When the men who tentatively won are shifted down (to make room for the two
>> women), their order is preserved (which in the above case means the men in
>> seats # 4 and # 5 are completely removed, and the man who was in position #
>> 3 is moved to position # 5, and the man who was in position # 2 is moved
>> into position # 3).

> This does not necesarily lead to proportionality within the five candidates.

Imposing a quota, by necessity, amounts to disturbing carefully balanced 
results.

In other words, if the calculated results achieve proportionality, then 
imposing a quota will disturb the proportionality of 
otherwise-proportional results.

Also this involves the issue mentioned above, namely that getting 
proportional results for a specific number of seats makes it difficult 
(impossible?) to add to, or remove from, the list and still also get 
proportional results for a different number of seats -- without making 
adjustments to earlier positions in the list.

I assume that the Green party is not allowed to submit multiple party 
lists and specify that "this party list is used if we win one seat, and 
this different party list should be used if we win two seats, and here 
is yet another party list that should be used if we win three seats, etc."

>> ...
>> Why is the second woman moved into position # 4 instead of position # 5?
>> Because presumably half of the Green-party voters are women, and presumably
>> you want proportional results if your party should win 4 seats.  (If the
>> quotas are met without needing any adjustments, then the second woman might
>> end up in position # 5, and this would be fair because the results imply
>> that quotas are no longer necessary to override other political priorities.)

> Both presumptions are wrong.

In this case the second woman should be moved into position # 5 -- which 
is the minimum quota-based requirement -- rather than moving her into 
position # 4.

Thank you for your questions.

Richard Fobes