[EM] Multiple Winner Elections

[Forest Simmons]

I would like to make a suggestion for a multiple winner proportional
method that is as good or better than any I have heard proposed so far,
short of the Proportional Approval Voting (PAV) that Michael Welford and I
proposed several weeks ago. (Full strength PAV would involve checking all
of the two candidate subsets, one-by-one on each ballot, so it would
probably be more elaborate than what you wanted.)

The method I recommend is a simple sequential version of PAV:

(1) Have the voters fill out approval ballots (identical to ordinary one
vote per voter ballots with instructions to vote for as many of the
candidates as they would like to support). 

(2) Completely eliminate all of the candidates that get fewer than 30% of
the vote. (Do not even put them back in for step 4 below.)

(3) Pick out the Approval Winner from among the  remaining candidates (the
candidate with the most votes). This is the first winner.

(4) Recount the ballots with this twist: All of the ballots that did NOT
approve of the first winner get counted twice.

The winner of step 4 is the second winner. If one of the winners is to
have special tie breaking privileges or be considered the chair, while the
other is to be considered the co-chair, then no known method is superior
to this one.

It could well be worth designing the chair/co-chair position to fit this
election method, since the method is superior in every way (including
simplicity and ease of implementation) to all of the competing methods for
that kind of arrangement.

Even if the two co-chairs are to be considered equal in every way, this
method is as good as any sequential method (like STV) for getting
proportional (or better) representation, and is more likely to get winners
with broad support than STV or any simple method (short of full PAV in
simplicity).

If you would like step by step examples, or have any questions, I would be
glad to help.

Forest

On Mon, 19 Feb 2001, Moe St. EverGreen wrote:

> What are the best choice(s) of voting system(s)
> for a multiple winner election?
> 
> I can believe there could be more than one depending
> on the type of election.
> 
> For instance, we will have a 2 person co-chair in an organization,
> where the idea is to balance any opposing factions 
> as they will likely occur.
> 
> What would be the best form of election?
> 
> I know Approval could be used (taking the top two), 
> but it seems very easily for a faction to have a strategy
> of running multiple candidates.
> 
> Cumulative seems a little like overkill, and I'm not sure
> how well it stands up against other systems.
> 
> I don't see how we could possibly use any form
> of Proportional for this.
> 
> And I worry that STV is just as bad as IRV.
> 
> The other situation is that we will have a large county executive
> committee, which we want to elect using some form of PR. 
> 
> The idea is that each candidate must choose to run 
> either unaffiliated, or as affiliated with one of our 
> activist groups or neighborhood groups (affiliation being 
> decided by a majority approval of that group).
> 
> Whatever the method of election counting, the seats would be filled
> in the order of any top winning unaffiliated winners first, 
> then the remaining seats would be proportioned out per the total 
> support each group received (with affiliated being a group), with the 
> seats for each group being filled in order of most support to least 
> support.
> 
> Since we are a county political party, we won't have parties within
> ourself, but we will very likely have factions and neighborhood groups
> which will need to have representation.
> 
> Please let me know of the best alternative methods we may use, and
> if we did use the system above, should we rank the votes, or use
> something similar to approval voting, etc., for the actual ballot
> and ballot counting.
> 
> - Moe.
> 
> 
> 
>