Dave Ketchum wrote:
Runoffs: Essential with FPTP unless one candidate receives a majority vote, for there is too great a chance for best-liked to not receive the most votes. Top-two runoff weakness is the chance for FPTP to have seen true best-liked as third. Of less value for methods that let voters better express their desires.
You might want to add that the second round of the runoff is strategy free, as there are only two candidates. Thus a runoff may have advantages beyond other methods if people strategize a lot (e.g. in small council elections). The strategy would then involve making the "wrong" top two survive to the second round, so the first round would have to use a method that is fairly resistant to strategy.
One (complicated) idea I've suggested earlier is to have a runoff with two Condorcet methods: the first surviving candidate is the winner of a good "honest voters'" method, while the second surviving candidate is the winner of a burial-resistant (though perhaps nonmonotonic, etc) method. If the voters are honest, the first winner prevails; if the voters strategize heavily, at least they can get no worse than what the second method provides.
It's probably overkill for a public election, but might be useful in small or intermediate size scenarios.
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