[EM] Approval-based replacement for jungle primary

Ted Stern dodecatheon at gmail.com
Thu Nov 29 13:27:03 PST 2018

Hi Rob,

The thread I was referring to was actually one that included the following
comment, which introduced a complementary approval candidate similar to
your own:


But my later suggestion was related, so no problem.

Regarding your modification suggestion, I'm not sure that you fixed
anything.  Including everyone above 50% approval potentially creates an
over-crowded ballot.  However, as Chris Benham states in the included post
above, Approval Winner plus complementary (or, as I like to call it,
*excluded*) approval winner could lead to Condorcet violation.

Let's imagine a Condorcet-like election with a score ballot with more than
two ratings, so it's not just approval.  Say 0 to 3, with any score above
zero indicating approval.

Infer rankings from the ratings (higher score ranks above lower score), and
tabulate the pairwise array.

Then advance the following candidates to the general election:  the Smith
set, plus the Approval winner, plus the AW-complement.  This group is
guaranteed to include the Condorcet winner, plus at least one other
candidate.  If desired, according to your criterion above, you could also
include the AW-runner-up.

On Thu, Nov 22, 2018 at 1:12 AM Rob Lanphier <robla at robla.net> wrote:

> Hi Ted,
> Hmm....I have a tweak to the proposal to run by you.  More below...
> On Wed, Nov 21, 2018 at 5:31 PM Ted Stern <dodecatheon at gmail.com> wrote:
> > I like the MAF proposal. I've posted in favor of PR approval based
> runoff methods before, almost exactly 2 years ago, in fact.
> Thanks!  My proposal comes with a bit of naivety about prior
> proposals.  In the past, I've sent an "oh, I have an idea" post it to
> this list, and then someone replies "you mean Coombs?" and I ask
> "what's Coombs?" and then someone (possibly after emitting a heavy
> sigh) composes a very educational email detailing what Coombs is.
> I'm assuming the proposal you're talking about is this one:
> http://lists.electorama.com/pipermail/election-methods-electorama.com/2016-November/001054.html
> I just read it, and I concur.  Applying proportional-style approval
> voting to electoral college selection is a neat idea.  The MAF step 2
> in my proposal seems to use a very similar mechanism to the one you
> describe.  My proposal below might be even more similar...
> > My only caveat would be that there is a theoretical possibility that
> including everyone who gets more than 50% approval could introduce a clone
> crowding effect.  Do you want any limits on the number?
> The clone problem has been in the back of my mind for a while; I'm
> glad you brought it up.  A solution that just occurred to me: what if
> we generalized the MAF step 2 mechanism.  So, here's the MAF rules in
> my blog post yesterday (er...make that Tuesday):
> 1. The candidate who receives the highest approval rating qualifies
> for the general election
> 2. If less than 75% approve of the leading candidate, then a second
> candidate (the “complementary candidate”), who maximizes the approval
> of the electorate, also qualifies
> 3. All candidates who receive over 50% approval also qualify for the
> general election
> For a dominant party like the Democratic Party in California in 2018,
> under this system, their motivation would be to run as many Democrats
> as possible, and hope they all make it to the general election.
> What if instead, for all candidates who qualify via step 1 or step 3
> (getting between 50% and 75% of the vote), an opposition candidate is
> chosen?  If the left-wing/right-wing model persists for a while, it
> basically means that every Democrat/Green/PeaceAndFreedom candidate
> who advances by getting 50% approval, there could be a
> Republican/Libertarian/AmericanIndependent who also advances.  If the
> Republican and Democratic parties remain dominant, there would
> probably be an R for every D, but of course, once people start getting
> comfortable approving an army of clones, it could be that clone
> coalitions form that bring in these third parties. For reference,
> here's the certified political parties in California:
> https://www.sos.ca.gov/elections/political-parties/qualified-political-parties/
> (and don't hold me to my assessment that
> "Democrat/Green/PeaceAndFreedom" == "left" and
> "Republican/Libertarian/AmericanIndependent == "right"...I'm a little
> uninformed about the nuances of our third parties, and also realize
> that, for example, Libertarians would balk at being called "right
> wing" in the left/right model)
> Advancing an army of clones invites an army of complementary
> candidates, so I suspect that would motivate partisan voters to be
> stingy about approving an army of clones, and to motivate
> parties/coalitions to thin their ranks a little before the primary and
> publish focused endorsements, and to motivate candidates to drop out
> before the primary if the field is too crowded.
> Perhaps a way of formalizing this mechanism would be to change to this
> set of rules:
> 1. Select the candidate who receives the highest approval rating.
> This is the "top candidate" and qualifies for the ballot
> 1a. If the top candidate (and any other candidate) receives greater
> than 75% approval, add these candidates to the "highly-approved
> candidate pool"
> 1b. If the top candidate receives less than 75% approval, add the top
> candidate to the "majority candidate pool"
> 2. If the top candidate has been added to the "majority candidate
> pool", also add a candidate to the “opposition candidate pool”.  To be
> added, this candidate must be the candidate which maximizes the
> "majority/opposition ballot satisfaction".  "ballot satisfaction"
> generally means voters approve of at least one candidate on a given
> ballot.  "majority/opposition ballot satisfaction" is for a ballot
> that only contains the "majority candidate pool" and the "opposition
> candidate pool".
> 3. For each candidate who receives over 50% approval, but less than
> 75% approval:
> 3a.  Add this candidate to the "majority candidate pool"
> 3b.  Add a candidate to the "opposition candidate pool" who maximizes
> the "majority/opposition ballot satisfaction" of the electorate (as in
> step 2)
> 4.  Eliminate all candidates from the "opposition candidate pool" who
> have an overall approval rating under 25%
> 5.  All candidates remaining in the "highly-approved candidate pool",
> the "majority candidate pool" and the "opposition candidate pool"
> advance to the general election.
> In the original MAF proposal, the "opposition candidate pool" (i.e.
> the "complementary candidate") is no more than one candidate.  In this
> proposal, the opposition candidate pool could grow to two candidates
> if two candidates are added to the majority candidate pool..
> This doesn't seem like a radical departure from the rules I described
> in my Tuesday blog post.  The added complexity bothers me, but this
> seems to solve a problem with the original proposal.  In the old
> proposal, the single complementary candidate is chosen as an
> alternative to the leading candidate, even if a third candidate is
> also added.  In this proposal, it would seem rare to advance just
> three candidates; either there's one candidate in each pool ("highly
> approved", "majority", "opposition") or there as a candidate pruned
> from the "opposition candidate pool" for being under 25% approval.
> My hunch: it would take at least 2-3 election cycles before more than
> two candidates advance to the general.  I suspect bullet voting would
> be common in early elections, and it would take a while before
> sophisticated campaign strategies emerge (e.g. like candidates
> endorsing each other, holding joint events, and advertising for one
> another).  Most elections would result in a single "majority"
> candidate, and an "opposition" candidate.
> I came up with the set of rules above as I was composing this email,
> because I wanted to make the rules fit the examples below.  My first
> draft had rules ensuring that if the majority candidate pool had N
> candidates, the opposition candidate pool would only have N-1
> candidates. In this version, it's possible for the opposition
> candidate pool to have just as many candidates as the majority
> candidate pool.  But it didn't match my examples below, and I liked my
> examples better than I liked my draft rules, so I rewrote the rules.
> Now that I have rules I like, I've tweaked my example scenarios to fit
> the rules:
> Test scenario #1: Let's say that seven candidates qualify to advance,
> and the top candidate only receives 55% approval.  It seems that the
> order that the primary candidates should enter their respective pools
> should be like this:
> #1 - Top candidate - first in majority candidate pool
> #2 - first in opposition candidate pool (complementing the top
> candidate in the majority pool)
> #3 - second in majority candidate pool (with 54% approval)
> #4 - second in opposition candidate pool (complementing the candidates
> above in the majority pool)
> #5 - third in majority candidate pool (with 53% approval)
> #6 - third in opposition candidate pool (complementing the candidates
> above in the majority pool)
> #7 - fourth in majority candidate pool (with 52% approval)
> #8 - fourth in opposition candidate pool (complementing the candidates
> above in the majority pool)
> In my original draft, the candidate with the lowest overall approval
> score would be eliminated from the opposition pool so that the
> majority pool had four candidates, and the opposition pool only had
> three, and thus only seven candidates advanced.  In my current rules,
> it's possible for eight candidates to qualify, but my new rule #4
> above ("Eliminate all candidates from the opposition candidate pool
> who have an overall approval rating under 25%") could knock it down to
> seven.  Or six,  Or even four.
> Test scenario #2: Let's say the top candidate gets greater than 75%
> approval. That's a pretty strong indication that the top candidate is
> the median candidate.  But if three other candidates also get greater
> than 50% approval, it only seems fair to give them a hearing in the
> general election.  Thus, when the top candidate gets greater than 75%
> approval, it seems the order should go like this:
> 1 - Top candidate - first in highly-approved candidate pool
> 2 - first in majority candidate pool
> 3 - first in opposition candidate pool (complementing the first
> candidate in the majority candidate pool)
> 4 - second in majority candidate pool
> 5 - second in opposition candidate pool (complementing the candidates
> above in the majority candidate pool)
> 6 - third in majority candidate pool
> 7 - third in opposition candidate pool (complementing the candidates
> above in the majority candidate pool)
> I originally wrote "I'm pretty sure it'd be possible to write a set of
> rules to achieve this.  I'm just not going to do it tonight".  I
> *think* I pulled it off.  That's why I didn't send this mail a couple
> hours ago.  Now I really should send this email.  :-)
> Rob
> p.s for those of you who prefer reading blog stuff on Medium (or feel
> like clicking on the applause link), here's the Medium version of this
> proposal:
> https://medium.com/@robla/replacing-the-jungle-primary-c1e844a5333b
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