[EM] Preferential voting system where a candidate may win multiple seats

Kristofer Munsterhjelm km_elmet at lavabit.com
Mon Jul 22 13:50:09 PDT 2013


On 07/22/2013 05:37 PM, Juho Laatu wrote:
> On 22.7.2013, at 16.43, Vidar Wahlberg wrote:

>> That might produce a sensible result, I'll see if I can modify the
>> code to do something like this.
>
> I think that approach is at least quite easy to explain and justify
> to the voters. A full quota is something that looks pretty much like
> a certain seat, and quota fractions look like possible seats.

Yes, a quota is easier to explain. Just consider my attempts at 
divisor-based STV analogs vs STV itself: the latter is far easier to 
understand.

On the other hand, quota-based systems have some peculiar properties. In 
party list, if you're using a quota method, it might happen that party X 
gains support while party Y loses support, yet Y gains more seats than X.

I guess that for party list, you could explain a divisor method pretty 
easily as well -- or rather, the Webster variant (multiply and round) 
would be fairly easy to explain:

"We would like each party to get a proportional share. So we divide each 
party's number of votes by some constant to get the sum to equal the 
number of seats in parliament.
But this will give fractional results, so we have to round the results 
since there's no such thing as a tenth of an MP.
But now the sum of seats may not add up to the number of seats in 
parliament. So we adjust the divisor."

In other words, it's the least possible change from the ideal situation, 
given that we can't have fractional MPs.




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