[EM] Another PAR, inspired by "conditional approval"

[Jameson Quinn]

I find cbenham's "conditional approval" idea interesting. It inspired me to
the following modification of PAR, which I'm temporarily calling PAR-prime:


   - Voters can Prefer, Accept, or Reject each candidate. Default is Accept.
   - Candidates with a majority of Reject, or with under 25% Prefer, are
   eliminated, unless that would eliminate all candidates.
   - The winner is the remaining candidate who has the most points, where X
   scores one point for each ballot where there are at least as many remaining
   candidates rated below X as there are above X.

This is the same as PAR if, as I suspect will be the most common case, only
1 or 2 candidates are not eliminated. But in a center-squeeze situation
where 3 candidates remain, the center candidate will get the points from
both sides, as they should. Also, in a simple Condorcet cycle with just 3
voting blocs, the minimax candidate will win.

This system has some strange turkey-raising possibilities, but no one
faction can profitably create a turkey from nothing; the only case where
turkey-raising works is if your faction likes the turkey the least, so it's
a strategy that's best avoided unless you know exactly how the rest of the
ballots will come out.

This system doesn't meet FBC if there is a voted Condorcet cycle; in that
case, it is good for the minimax loser faction to eliminate their true
favorite (though of course it's even better for them to trick the faction
which puts their favorite second to do so). But it does meet FBC in all the
non-cyclic scenarios I can construct, including chicken dilemma and center
squeeze, so I think favorite betrayal will not be a problem in practice.

So in practice, I think this is the most strategy-free system I know of
besides SODA. I suspect that with some work, I could find a better wording
for step 3. It's a good system, but I'm not sure it's worth it over
standard PAR.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20161104/b3176336/attachment.htm>