[EM] Holy grail: PAR with FBC?

[Jameson Quinn]

2016-11-10 9:04 GMT-05:00 C.Benham <cbenham at adam.com.au>:

> 1. Voters can Prefer, Accept, or Reject each candidate. Default is Accept.
>
>
> This seems to assume that all the voters are interested in all the
> candidates and like checking boxes, whereas
> I should think that a lot of voters would be only interested in their
> favourite and content to keep voting the
> way they did under plurality (and would presumably continue to do so under
> Approval).
>
> They should be allowed to continue giving the most effective vote possible
> by simply giving a "Prefer" rating to their
> favourite.  In-effect penalising such voters for forgetting to also give
> "Rejects"  to all their non-favourites is unfair
> and dumb.
>
> It will give voters who aren't fans of the new method extra reason to
> resent it.  Suppose that a strong candidate
> from an established party very narrowly loses just because some of his/her
> supporters forgot to give out "Rejects".
> Don't you think that might fuel a movement to dump the method?
>

My thinking was that in most real-world situations, you'd only have to
check one prefer and one reject to get maximum effectiveness, and it would
be obvious which to reject.

But I see your point. So I'm changing the method to: "Default is reject for
voters who do not explicitly reject any candidates, or accept for those who
do."

>
> 2.Candidates with a majority of Reject, or with under 25% Prefer, are
> eliminated, unless that would eliminate all candidates.
>
>
> I don't like arbitrary thresholds.  Obviously this causes failure of
> Irrelevant Ballots Independence. But also there is the problem
> that the final exact number of valid ballots can be disputed and/or take
> quite a while to establish.
>
> Postal votes can take a while to come in, or may be mislaid and later
> found. The validity of certain ballots can be disputed and
> the subject of legal proceedings.  Some people might have initially been
> denied the right to vote, but then succeed in having that
> over-turned and are then allowed to vote.
>
> It is much better if the algorithm just (more-or-less directly) compares
> the candidates with each other rather than measure them against
> arbitrary percentage-of-the-votes thresholds.
>

If the number of uncounted ballots is enough to sway the election using a
threshold, it has every chance of being enough to sway the election without
thresholds. Only under the assumption that all uncounted ballots are
irrelevant does your objection apply particularly to threshold methods.

...

I'm giving up on the method I'd proposed earlier. It's now called "CPAR",
for Complicated PAR. But I do have a new patch to PAR to make it pass FBC:


   1. Voters can Prefer, Accept, or Reject each candidate. Default is
   "Accept"; except that for voters who do not explicitly reject any
   candidates, default is "Reject". Voters can also mark a global option that
   says: "I believe that voters like me should be the first to compromise."
   2. Candidates with a majority of Reject, or with under 25% Prefer, are
   eliminated, unless that would eliminate all candidates. If a candidate
   would have been eliminatable considering all the "prefer" votes they got on
   "compromise" ballots as "rejects", then they are considered "eager to
   compromise"
   3. The winner is the non-eliminated candidate with the highest score.
   Candidates score 1 point for each voter who prefers them, and 1 point for
   each voter who accepts them and prefers only candidates who were eliminated
   or eager to compromise.

The above method meets FBC, except in vanishingly rare cases where multiple
candidates are simultaneously at a threshold (analogous to perfect ties).
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