[EM] Rethinking Burial Detection Runoff

[Forest Simmons]

It looks like James Green Armytage's adaptation of Dodgson and Hare boils
down to going as far as possible with repeatedly eliminating non- Smith
candidates during rounds of negotiations and voluntary candidate
withdrawals. Then that process stalls, knock it off dead center by
eliminating the candidate with the fewest first place votes, before
resuming the negotiations, reballotings, candidate withdrawals, etc,
punctuated with additional IRV style Elimination steps when necessary.  If
that process goes on beyond some established number of steps, then you
finish off with IRV or Benham applied to the remaining candidates.

It sounds messy and complicated, but with any luck the original Smith set
will be small, and the negotiations and withdrawals with satisfactorily
resolve things with only one or two sets of ballots.

Armitage is making a heroic effort to resolve the top cycle without going
outside the Universal Domain except for informal, low pressure negotiation
sessions encouraging candidates to withdraw and voters to reconsider their
votes.

He never mentions Dodgson's simpler and more elegant method that we call
Asset Voting or Candidate Proxy ... because that would be a much more
radical departure from Universal Domain.

For the same reason he makes no mention of his previous progress with
Pairwise principles applied to Score/ Range style ballots.

I think that just plain Benham with a one time candidate withdrawal option
would get most of the benefit of the proposal without the perceived
complexity.

Here's an idea that came to me while reading the paper:

At every stage eliminate the pairwise loser PL of the two remaining
candidates with the smallest minimum pairwise support ... along with every
candidate defeated by PL.

When there is only one candidate left, elect the sincere winner between it
and the last PL candidate.

Indignant voters can say, "Thank you very much, but I always vote
sincerely," while admitted sinners can include a second set of ballots for
use in the sincere binary runoff.

I suggest using min PS instead of first place votes because transferred
first place votes require additional passes through the ballots, while min
Pairwise Support counts do not, since all of the necessary information is
in the initial pairwise support matrix ... and the fewer the uneliminated
candidates, the more accurately the minPS values reflect the first place
transferred vote counts.

fws

On Thu, Jun 15, 2023, 2:48 AM Kristofer Munsterhjelm <km_elmet at t-online.de>
wrote:

> On 6/15/23 07:47, Forest Simmons wrote:
> > Chris,
> >
> > I like your new Condorcet method, and consider it to be a much more
> > practical suggestion than any of my sincere CW finder ideas currently in
> > progress.
> >
> > The ballot profile you provided to illustrate your LV Sorted Margins
> > burial resistant method, ended up electing A, which we considered to be
> > better than electing B, because we thought that with some positive
> > probability the ballot profile might be a result of the B faction's
> > insincere order reversal .... changing sincere 44 B>A to 44 B>C, i.e.
> > the B faction burying A under C ... so that electing B, like just about
> > every other method under the sun, would encourage bad behavior.
> >
> > Is it insulting to voters to build in safe guards that make insincere
> > truncations or burials less likely to pay?
> >
> > Is it insulting to lock your front door when leaving town for a few dsys?
>
> > Going outside the strict Universal Domain by allowing truncations, equal
> > rankings, approval cutoffs, or other levers, offer additional
> > expressiveness that can reduce incentives for burial, compromise, etc.
>
> James Green-Armytage has another suggestion for deterring burial:
> https://www.jamesgreenarmytage.com/dodgson.pdf
>
> I haven't read it in detail, so perhaps the devil's in the details about
> "plausible assumptions about how candidate decide". But what do you
> think of that method?
>
> >
> > I've been experimenting with how far we can get with two sets of ballots
> > ... one possibly strategic set, for the purpose of determing the
> > finalists and runoff order ... and the other set dedicated solely to the
> > kind of runoff that elects the sincere CW whenever there is one.
>
> This is still an interesting venue, of course. I've updated the
> Electowiki page about Condorcet loser to include information that a
> manual runoff method always passes honest Condorcet loser (assuming no
> drop in turnout).
>
> At some point I would like to do a minimum strategy evaluation of
> methods with two rounds, but I've currently been occupied with cleaning
> up some other code in my election simulator quadelect so that I can
> automatically check for clone failures, monotonicity, etc. the same way
> I can check for strategy failures; and so that I can classify strategy
> failures as burial, compromise, or other.
>
> Maybe, eventually!
>
> -km
>
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