I noticed on your page that you suspect that all multi-winner methods fail
participation. I don't think that's the case. I would suggest that Forest
Simmons's Proportional Approval Voting passes it. Also I think my versions of
Proportional Approval Voting and Proportional Range Voting pass.
From: Ted Stern <[email protected]>
To: Election Methods <[email protected]>
Cc: Ted Stern <[email protected]>
Sent: Monday, 3 October 2011, 19:45
Subject: Re: [EM] PR approval voting
I'd like to stick my oar in here, to point out that I have an
implementation of Range Transferable Vote, which can be used with
Droop or other quotas, that implements PR.
Code for it is located here:
https://github.com/dodecatheon/range-transferable-vote
It reduces to Approval Transferable Vote in the case of range(0,1).
I had to make one change to it recently to fulfill the Droop
proportionality criterion, which states that if a faction distributes
its votes among L candidates, and has enough votes to elect K <= L
quotas, then the method will elect K candidates from the set of L
candidates.
For RTV, this meant that I had to find a way to elevate range
preferences in the event that no candidate achieves a quota.
The way I implement this is to increase non-zero ratings incrementally
(up to maximum score) until at least one candidate makes quota.
This pushes RTV into the territory of Bucklin-style methods, and
therefore it does not satisfy the Independence from Irrelevant
Alternatives criterion, even in the single-winner case.
Ted
On 01 Oct 2011 09:25:45 -0700, Toby Pereira wrote:
>
> Presumably this could also be used for range voting with a fairly
> simple modification. It would just set a limit on the fraction of
> someone's vote that could be used for each candidate. If you scored
> a candidate 3 out of 10, then no more than 0.3 of your vote could go
> to that candidate, regardless of whether the rest remained unused.
>
>
> From: Ross Hyman <[email protected]>
> To: [email protected]
> Sent: Saturday, 1 October 2011, 5:07
> Subject: [EM] PR approval voting
>
> The following PR approval voting procedure is an approval limit of Schulze STV
>
> A score for each candidate set is determined in the following way: ?? The
> vote of each ballot is distributed amongst the ballot's approved candidates
> in the candidate set.? The score for each candidate set is the largest
> possible vote for the candidate in the set with the smallest vote.? The
> candidate set with the highest score wins the election.
>
> example: 2 seats
> approval voting profile
> 10 a
> ? 6 a b
> ? 2 b
> ? 5 a b c
> ? 4 c
> The possible candidate sets are: {a b}, {a c}, and {b c}.
>
> score for {a b} determined from
> 10 a
> ?11 a b
> ? 2 b
> score for {a b} = 11.5
>
> score for {a c} determined from
> 16 a
> ? 5 a c
> ? 4 c
> score for {a c} = 9
>
> score for {b c} determined from
> ?8 b
> ?5 b c
> ?4 c
> score for {b c} = 8.5
>
> set {a b} wins.
>
>
> Schulze uses a maximum flow algorithm to distribute the votes optimally on
> each ballot for each candidate set.? Here is another algorithm.
>
> v_i,a is the vote assigned to candidate a from the ith ballot.? The optimal
> v_i,a is determined iteratively.
>
> 1) Initially, the vote for each ballot is distributed equally between all the
> candidates in the candidate set that are approved by that ballot.?
>
> 2) The total vote for a candidate in the set is determined from v_a = sum_i
> v_i,a.? The lowest vote is a lower bound for the candidate score.
>
> 3) Form the adjusted vote w_i,a =? v_i,a/v_a.?
>
> 4) The adjusted vote for each ballot is w_i = sum_a w_i,a.
>
> 5) The new v_i,a = w_i,a / w_i.? Proceed to step 2.
>
>
>
> ?? ? ? ??
>
>
>
> ?
>
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>
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