[EM] Single Non-Transferable voting + Approval (or Approval Sorted Margins) as a primary

Ted Stern dodecatheon at gmail.com
Fri Sep 18 15:24:07 PDT 2020

Hi Chris,

Taking your points in reverse order:

Direct democracy would be great, but in the US, at least, it's a long way
off until we can elect representatives who will put us on the path to get

I wouldn't call STAR an abomination, but it doesn't seem to have a firm
foothold in either utilitarian or majoritarian philosophies, and IMO it
fails to find the centroid of voter sentiment even in an idealized
framework like Yee plots.

The proposed method was intended to be a winnowing election in the case
that there are more than 7 candidates, and remove some clone-type of
duplication of candidates at the same time.  So yes, it would replace all
party primaries.  Robert Bristow-Johnson points out that California has an
open primary. Yes, I am aware of that -- Washington State's is similar. It
is a top two single vote primary.  The problem with that is, as pointed out
by Robert and Richard, that some parties might not be represented. Hence
the winnowing primary, allowing more candidates to represent a larger
portion of the electorate.

STV is an interesting idea, although in the sense you describe it, it looks
more like extended IRV. I would like to see someone implement that, but the
other aspect of my testbed script is that it uses score ballots, and I
don't see an easy way to do that.  But STV at least has the virtue of being
hand-countable. I would run it until the smallest candidate total is above
5%, though, up to a max of 7 candidates instead of 6.


On Fri, Sep 18, 2020 at 9:48 AM C.Benham <cbenham at adam.com.au> wrote:

> Ted,
> I haven't been thinking very much about this topic lately.  But I have one
> or two ideas.
> Abolish the party primaries and just have one big "primary".   Use  STV to
> one-at -a-time eliminate candidates until the remaining candidate with the
> fewest votes has a tally that is at least X (say 15)%
> of the total of the unexhausted ballots (i.e. those that show some
> preference among uneliminated candidates).
> In the "general election" this should limit the field to a manageable
> number (no more than 6).
> ("STAR" is an abomination.)
> At least as important in the current period  is election integrity and
> thinking of ways to use technology to implement direct democracy or some
> hybrid of direct and representative democracy.
> Chris
> On 18/09/2020 6:13 am, Ted Stern wrote:
> I've implemented the primary idea I proposed last month. It's available in
> my github repository as *winnow.py*. The repo is located at
> https://github.com/dodecatheon/approval-sorted-margins/
> The code is designed to be used as a test bed for several
> score-ballot-based methods.
> The default method for advancing candidates is Preference Approval Sorted
> Margins.  It's basically Approval Sorted Margins, but I interpret any
> non-zero score as approval, so I'm calling the higher level of approval
> "Preference". As I proposed before, any ballots approving (non-zero score)
> of the currently advancing winner are removed completely, then tallies are
> done on the remaining ballots until no more candidates remain or 95% of the
> ballots are used up, or a maximum number of candidates (default 7) has been
> reached.  In each candidate advance round, candidates with remaining
> approval below the threshold (default 1%) are dropped.
> Approval, Score, STAR, Vote 3-2-1, and Score Sorted Margins are supported,
> and just for the sake of completeness, I also include Preference (like
> approval but using explicit "preference" cutoff), and Top-rating.
> It is designed to be used on a linux command line with python 3.7+ that
> includes numpy.  I recommend getting the Anaconda (or mini-conda) package.
> There are a lot of commandline options.
> From the standpoint of practicality, say in the event of a 100+ candidate
> jungle primary, this type of primary would be relatively simple to
> implement for Approval, Score, Preference or Top-Rating.  Slightly more
> difficult would be STAR or Vote 3-2-1.  Finally, any method that requires
> the pairwise array, such as PASM or SSM, would be most complicated, and
> would probably require some sort of candidate pruning below an approval
> threshold (to get the number of candidates below 20 or so) to be at all
> feasible.
> On Fri, Aug 7, 2020 at 2:33 PM Ted Stern <dodecatheon at gmail.com> wrote:
>> Over the years a number of people on this list (e.g. Rob Lanphier, myself
>> and others) have proposed various methods for using Approval in primary
>> elections.
>> There are arguments to be made for using other PR methods, but it seems
>> to me that SNTV is ideally suited to be a primary method, since it resists
>> pushover and doesn't tend to overrepresent parties.
>> Using Approval as a base method, single non-transferable approval voting
>> would look like
>>    - Advance Approval winner and Approval runner-up
>>    - Deweight to zero all ballots approving of AW.
>>    - Repeat until some threshold (e.g. 90%) of ballots have been used up:
>>       - Advance approval winner on the current remaining ballots
>>       - Deweight ballots approving of latest winner to zero
>> The advantages here are
>>    - Relative simplicity -- No complicated reweighting algorithms, so
>>    each recount for the next approval winner is faster than the previous, and
>>    can even be done by hand.
>>    - Each winner (other than the first approval runner-up) will tend to
>>    be from a different party or faction of a party.  There may be some overlap
>>    from also advancing the overall Approval runner-up, but if the total AW and
>>    ARU are from the same party, it gives them an advantage under Approval to
>>    have a similar candidate for comparison.
>>    - Most groups will be represented in the General election.
>>    - Pushover strategy is disincentivized by complete deweighting, so
>>    parties should not be threatened by strategic promotion of their worst
>>    candidate. There is some possibility that voters would do that regardless,
>>    but the effect should be no worse than in current top-two elections.
>>    - Modifications could include:
>>       - Stop advancing candidates when the highest approval on remaining
>>       ballots drops below a threshold. For example, if the total deweight
>>       threshold is 90%, if the latest winner has less than 5% approval on
>>       remaining ballots (half the complement of 90%), break the loop.
>>       - Stop when a certain number of candidates have advanced. For
>>       example, if using the 5% rule above, it is possible that 10 to 15
>>       candidates could advance to the General, defeating the winnowing purpose of
>>       a primary. It seems reasonable to stop at 5 or 6 candidates.
>>       - Use a different method other than simple Approval.
>> I would be perfectly satisfied to have SNTAV as a primary method, but if
>> one can handle a bit more complexity (say in smaller groups), it would be
>> reasonable to use Approval Sorted Margins as the base method:
>>    - Use Ranked or Rated ballots with explicit Approval Cutoff. If not
>>    explicitly specified, cutoff is at zero-rating or last ranking.
>>    - Advance Approval Sorted Margins winner to general election
>>    - Deweight to zero all ballots approving of AW.
>>    - Repeat until some threshold (e.g. 90%) of ballots have been used up:
>>       - Advance ASM winner on the current remaining ballots
>>       - Deweight ballots approving of latest winner to zero
>> For public elections, I think the SNTAV approach I outline above, with a
>> 90% threshold, 5% minimum remaining approval, and limited to 6 candidates
>> (4 approval winners and 1 top approval runner-up) gives enough room to
>> enable more parties to develop.
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