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My criticism of RCV is more basic: in RCV, ranking someone too high can in some cases cause them to lose. That's really weird, and we probably shouldn't use an

by elihu 6y ago

My criticism of RCV is more basic: in RCV, ranking someone too high can in some cases cause them to lose. That's really weird, and we probably shouldn't use any voting system that has that property (i.e. it fails the monotonicity criterion). Problems generally arise when there is a third candidate who is competitive with the other two. Generally, it's safe to vote for your preferred candidate if they're either in a strong position and will probably win or they have no hope of winning. In between those poles, you might be harming your candidate if you put them first in a 3-way (or more) contest. Approval voting solves the third party spoiler problem better than RCV does, and it doesn't introduce any weird new problems. Therefore, I think it's a better option than RCV for anyone considering a switch from first-past-the-post. (Range voting and STAR voting are also pretty good.)

ruytlm 6y ago
Perhaps I am suffering a failure of imagination, but in what circumstance does "ranking someone too high .. cause them to lose"? Edit: Found this[0] talking about it; what remains unclear to me is whether this should be seen as "this hurts my candidate" over "this result better reflects the electorate". [0]: https://www.youtube.com/watch?v=JtKAScORevQ https://www.youtube.com/watch?v=JtKAScORevQ
- elihu 6y ago
  That's an example. One can argue about whether the "bad" candidate should have actually won in that scenario, but what's strange is when you have a situation where the "good" candidate would have won if only some group of voters hadn't put them first. I think at the root of it is that removing the candidate with the least number of first-place votes is kind of an arbitrary way of eliminating candidates. Maybe that candidate should have been eliminated, but maybe they were an ideal compromise candidate, tolerated by most voters even if not their first choice. Perhaps RCV might be significantly improved if one were to eliminate by borda count instead of least-first-place-votes, but that's not the system that's been advocated widely in recent years.

by elihu 6y ago

ruytlm 6y ago

Perhaps I am suffering a failure of imagination, but in what circumstance does "ranking someone too high .. cause them to lose"? Edit: Found this[0] talking about it; what remains unclear to me is whether this should be seen as "this hurts my candidate" over "this result better reflects the electorate". [0]: https://www.youtube.com/watch?v=JtKAScORevQ https://www.youtube.com/watch?v=JtKAScORevQ

elihu 6y ago
That's an example. One can argue about whether the "bad" candidate should have actually won in that scenario, but what's strange is when you have a situation where the "good" candidate would have won if only some group of voters hadn't put them first. I think at the root of it is that removing the candidate with the least number of first-place votes is kind of an arbitrary way of eliminating candidates. Maybe that candidate should have been eliminated, but maybe they were an ideal compromise candidate, tolerated by most voters even if not their first choice. Perhaps RCV might be significantly improved if one were to eliminate by borda count instead of least-first-place-votes, but that's not the system that's been advocated widely in recent years.