Clinton Mead wrote:
What would be the simplest paper count that will produce a winner in the smith set?

I'm not completely sure how your method works, but how about this?

Count the number of ballots on which each candidate is ranked (in any position). Call each candidate's count his "approval score". Then while there is more than one candidate left, eliminate the pairwise loser of the two remaining candidates with the least approval score.

Eliminating losers won't turn a ranked candidate into a non-ranked candidate (or vice versa), so unlike IRV, you don't have to do a recount for every round.

It should also pick a winner from the Smith set. Say all but one of the Smith set candidates have been eliminated. Then the remaining Smith set candidate will, by definition of the Smith set, beat everybody else pairwise, and so nobody will be able to eliminate him. Therefore, that remaining Smith set member will be elected. QED.

The counting burden isn't that hard, either: you need one pass to calculate the approval scores, and then (n-1) (for n candidates) pairwise counts. I don't think you can do better than (n-1) pairwise counts and still be sure to elect someone in the Smith set.

You could replace the approval count with a Plurality count to get something simpler, but that could also be unfair to Smith set candidates that have few first place votes, and it wouldn't be consistent: eliminating candidates from a Plurality count would mean other candidates could be exposed, and so you'd have to recount as in IRV.

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