[EM] Multiple Winner Elections

[Bart Ingles]

Subject: 
            Re: [EM] Multiple Winner Elections
       Date: 
            Mon, 19 Feb 2001 14:20:37 -0800
      From: 
            Bart Ingles <bartman at netgate.net>
        To: 
            "Moe St. EverGreen" <evergreen at lovemail.com>
 References: 
            1





"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.

Approval isn't really recommended for multi-seat elections, at least not
where some degree of proportionality is desired.  STV and other methods
seem to me to be overkill for a two-seat election.

Cumulative voting should actually be quite simple in this situation: 
Each voter has two votes, and is free to give both to a single
candidate, or to give one each to two candidates.  There is no need for
fractional votes with only two seats, and with only two seats voter
strategy should be quite manageable.

The only thing simpler (at least administratively) would be Single
Non-Transferable Vote (SNTV), actually the minimal form of Limited
Voting.  Here each voter gets one vote, period.  With ideal voter
strategy, this method is actually mathematically equivalent to
Cumulative Voting.  So with two factions, of 65% and 35% respectively,
both are guaranteed a seat provided all of the smaller factions's voters
vote for the same candidate (the smaller faction should only run one
candidate to prevent vote-splitting).  If the factions were sized
70%/30%, then the larger faction could in theory run two candidates,
with half of the voters voting for each candidate, and win both seats
with 35% each, and the smaller faction would be excluded with only 30%
(the same as with other proportional systems).

Both Cumulative Voting and SNTV might be worth considering.  CV is a
little more complicated administratively (but not much), while SNTV puts
more of a burden on voters & candidates to determine best strategy.  Not
much more of a burden, though -- so long as the largest faction does not
outnumber the second largest by 2:1, then all voters under CV should
give both votes to a single candidate, making CV functionally (as well
as mathematically) equivalent to SNTV.

If there is a single faction with more than a 2:1 advantage, SNTV might
indirectly favor a smaller group (compared to cumulative voting) by
making it more difficult for the large faction to allocate their votes
among two candidates.  You will need to decide whether this is desirable
or undesirable.


As for the larger ExComm, I think it depends what you mean by "large". 
If something like 5 or 7 seats, then Cumulative voting would still be
somewhat feasible; much larger than that you will definitely need a
different system.

Bart Ingles


> 
> 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.