[EM] Election methods in student government...

[Chris Benham]

Tim Hull wrote:

> So far, all I have came up with which seems to potentially be a good 
> method is a variant of sequential proportional approval voting.  Under 
> the system, single winner elections would be simple approval voting.  
> However, for multi-winner elections each student would begin with a 
> set number of "points" equal to the number of seats to be elected.  
> Votes would be counted as in normal SPAV, and each weighted according 
> to the number of points each student has remaining.  Every time a 
> voter elects one of their choices, they would "use up" one of their 
> points.  This seems a little more understandable than standard SPAV, 
> and it hurts groups that share some preferences with the majority less.


Tim,
Your gives voters a very big incentive to not vote for someone who they 
believe will win anyway.
In the extreme case there could be a very popular candidate X that fails 
to be elected because everyone "knew" that X would win the first seat,
so didn't vote for X to avoid losing ("using up") a point.

Take this election for 4 seats.

11: ABCD
05: D
09: EF

By my calculations with your  suggested method, it elects  DEAF. The ABC 
faction erred by approving D.

11: ABC
05: D
09: EF

Now the winners are AEBF.  That isn't a proportional or fair result. D 
has a Droop Quota and should be elected (or squeezed out in a tiebreaker,
but here the EF "list" easily wins the last seat). The winners should be 
D, two from ABC and one from EF.

For a good single-winner method, I suggest DMC(Ranking). Voters rank 
candidates they approve, equal-ranking allowed. Elect the Condorcet winner
if there is one. Otherwise eliminate the least-approved candidate until 
one of the remaining candidates X is pairwise undefeated by any of the other
remaining candidates. Elect the first X to appear.

I also very much like the "full" version of DMC (that allows voters to 
rank among unapproved candidates by entering an approval cutoff/threshold).
Even  "3-slot DMC" that uses a 3-slot ratings ballot, top two slots 
interpreted as approval and default placement  in bottom slot, is in my 
opinion
better than Approval or any other 3-slot method.

http://wiki.electorama.com/wiki/DMC

I might have some PR suggestions in a later message.

Chris Benham