[EM] PR-STV with approval based elimination

[Kristofer Munsterhjelm]

Jonathan Lundell wrote:
> On May 1, 2009, at 6:02 AM, Raph Frank wrote:
> 
>> 2009/5/1 James Gilmour <jgilmour at globalnet.co.uk>:
>>> One problem with abandoning LNH is that it opens the way for 
>>> strategic voting, that is, when a voter ranks the candidates in
>>> some
>>> order other than the sincere 'first to last' order of preference 
>>> because the voter knows that some feature of the voting system will
>>> enhance the changes of the real high preferences being elected if the 
>>> rankings marked on the ballot are distorted in a particular
>>> way.
>>
>> Unfortunately, strategy is often a part of methods that encourage 
>> compromise.
> 
> Part of the point of PR, it seems to me, is to represent the voters, or 
> groups of voters with similar views, as accurately as possible, and to 
> push compromise to the resulting legislative body, where compromising 
> can be worked out dynamically one decision at a time, with discussion 
> and analysis.
> 
> Forcing the voters to make a rather "blind" compromise in advance 
> through strategic voting may be a necessary evil for single-seat 
> elections, but I don't agree with the notion that we ought to encourage 
> it in a PR system.

Any PR system would have elements both of compromise beforehand and 
compromise in the legislative body. That is, since there are a limited 
number of seats, it's not possible to give everybody a seat perfectly 
representing their opinions.

Inasfar as the groups are large enough that the method can represent 
them in the assembly without compromising a larger group, there can be 
direct representation; but when that is not possible, there has to be 
compromise. Also, when picking the representatives within each group, 
there has to be compromise.

If there are two seats and the "left" and "right" factions are of equal 
size, and both have respective centrists, the outcome should have a 
"left centrist" (which is close to the median voter of the left faction) 
and a "right centrist" (which is close to the median voter of the right 
faction). That there is one member of the left group and one member of 
the right group in the outcome is explicit proportional representation, 
but that each representative is a centrist within his group is compromise.