[EM] Strategy-free criterion

Closed Limelike Curves closed.limelike.curves at gmail.com
Thu Jun 13 18:16:55 PDT 2024


>
> I am grateful for your work and I still think about how to encode the
> Schulze method into concise legislative language.  I can do it for MinMax,
> sorta do it for Ranked Pairs, but decently concise legislative language in
> English for Schulze is elusive.  If the language appears impenetrable to
> policy makers, it ain't gonna get anywhere in legislation.  That's one
> reason I decided that "straight-ahead Condorcet" with a "completion method"
> is the most likely sell.

Schulze generalizes Condorcet very simply by allowing *indirect* beats to
be counted as well as direct ones. The definition is actually very
intuitive and easy to describe in words:
1. A candidate has a *direct win* over another candidate if the first
candidate is ranked higher than the second by a majority of voters.
2. An *indirect win* or *chain *is a series of direct wins going from one
candidate to another.
3. The *strength* of a direct win is equal to the number of votes for the
candidate preferred by a majority of voters.
4. The *strength* of an indirect is equal to the strength of the weakest
link in that chain (c.f. a chain is only as strong as its weakest link).
5. One candidate *defeats* another if the first candidate has a
stronger chain going to the second candidate than vice-versa.

However, there's some real problems here. The biggest is that legislators
and voters are not competent or intelligent enough to follow simple
instructions. I give a 30% chance that, *even if you hand them a prewritten
bill*, the legislators will muck around with it and accidentally implement
Schulze(margins), i.e. turkey-winning Schulze; or Schulze(pairwise
opposition), i.e. Schulze with plurality failure.

Second, even if they didn't, I don't trust them enough to expect whatever
software lets them calculate the results will be thoroughly tested. "But
there's plenty of free, open-source, off-the-shelf implementations of
Schulze! It can't be that hard to just pick one and—" *is exactly what I
used to say about IRV*.

Finally, even if the legislators get it got it right, I don't really trust
voters to use it correctly. In particular, I'm starting to doubt that
voters have the intelligence or understanding needed to play good
strategies that elect the Condorcet winner in Schulze or RP, because
they're not immediately obvious. *Maybe* they can work it out if you make
the strategy blatantly obvious with implicit approval, but I doubt they
could otherwise. I'll send an email with more details soon.

On Thu, Jun 13, 2024 at 12:15 PM robert bristow-johnson <
rbj at audioimagination.com> wrote:

>
>
> > On 06/13/2024 11:20 AM EDT Markus Schulze <markus.schulze8 at gmail.com>
> wrote:
> >
> >
> > Hallo,
> >
> > in 1997, I proposed the following version for the
> > strategy-free criterion:
> >
> > *************************************************
> >     "X >> Y" means, that a majority of the voters prefers
> >     X to Y.
> >
> >     "There is a majority beat-path from X to Y," means,
> >     that X >> Y or there is a set of candidates
> >     C[1], ..., C[n] with X >> C[1] >> ... >> C[n] >> Y.
> >
> >     A method meets the "Generalized Majority
> >     Criterion" (GMC) if and only if:
> >     If there is a majority beat-path from A to B, but
> >     no majority beat-path from B to A, then B must not
> >     be elected.
> > *************************************************
>
> Okay, this is elegant (once the notion of a beat-path is understood).
> Now, if there is a cycle, isn't there a majority beat-path from B to A?
> Can the set of candidates, C[], be empty, so that it's simply B >> A?
>
> > See:
> >
> http://lists.electorama.com/pipermail/election-methods-electorama.com/1997-October/001570.html
>
> Wow, I knew you were around back in the olden days, Markus.  I just didn't
> know it went back to the previous millennium.  And I did not know MO's
> participation also goes back to the 90s.  I only started in 2009 just after
> the Burlington IRV election.  A FairVote apologist in Burlington, Terry
> Bouricius (https://en.wikipedia.org/wiki/Terry_Bouricius), told me about
> the EM list.  (He has recently authored a new book plugging sortition:
> https://democracycreative.com/The-Trouble-With-Elections )
>
> I am grateful for your work and I still think about how to encode the
> Schulze method into concise legislative language.  I can do it for MinMax,
> sorta do it for Ranked Pairs, but decently concise legislative language in
> English for Schulze is elusive.  If the language appears impenetrable to
> policy makers, it ain't gonna get anywhere in legislation.  That's one
> reason I decided that "straight-ahead Condorcet" with a "completion method"
> is the most likely sell.
>
>
> https://legislature.vermont.gov/Documents/2024/Docs/BILLS/H-0424/H-0424%20As%20Introduced.pdf
>
> That one is Condorcet-Plurality (because that was the simplest completion
> method), but I think next time around, I'll try to convince them to do
> Condorcet-TTR which is, for three significant candidates, identical to
> Condorcet-IRV.
>
> --
>
> r b-j . _ . _ . _ . _ rbj at audioimagination.com
>
> "Imagination is more important than knowledge."
>
> .
> .
> .
> ----
> Election-Methods mailing list - see https://electorama.com/em for list
> info
>
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