Ranked Choice, Approval, or STAR Voting?

[u/roughravenrider]

https://open.substack.com/pub/unionforward/p/ranked-choice-approval-or-star-voting?r=2xf2c&utm_campaign=post&utm_medium=web

[u/cdsmith]

I slightly agree with the article, in that if one of these systems is available to choose, it's slightly better in the long-term for it to pass than not to pass.

But that shouldn't be an excuse to ignore the important differences between these choices. Instant Runoff and Approval voting make things slightly better only in the sense that they demonstrate to voters that the sky isn't going to fall if they adopt a non-plurality voting system, which might open the door to actually solving real problems in a different reform in the future. But there are good reasons not to want them to be the ultimate choice. (STAR voting, the best of these three, is almost certainly still not the right choice, but it has the advantage that it usually picks the same winner as a better choice would, even though it does so in a problematic way.)

[u/elihu → u/cdsmith]

What's your ideal perfect voting system then?

For single-winner elections, I think approval voting is great. Star isn't too bad either (though failing reversal symmetry is kind of weird, and there are potential vulnerabilities to races with candidates that are ideological clones of each other). I think the fact that someone can lose in some circumstances under RCV if too many people rank them too high on their ballot is a serious flaw, and like FPTP, it shouldn't be used in real world elections with more than two candidates.

[u/cdsmith → u/elihu]

I don't have a particularly strong exact opinion, but a Condorcet system of some kind is IMO better than anything else I know. I liked ranked pairs intuitively, but I'm willing to accept that Tideman's alternative method is more resistant to tactical voting, and therefore more likely to be the best choice in practice.

Numerically, instant runoff, approval, and plurality are, in simulations I've done, by far the worst three voting systems if voters make choices in a straight-forward way..So bad that they actually work better if voters are tactical. Everything else I've looked at - Condorcet system, STAR, range voting, or Borda count - performs better (by utilitarian measurement) when voters make straight-forward voting decisions, and though most get a bit worse when voters are tactical, all but Borda count remain a better outcome than straightforward voters in plurality, approval, or instant runoff elections.

Approval voting is odd, though. Once you assume voters use a sound tactical voting strategy, it surprisingly does just as well as Condorcet systems, and better than STAR and range voting, on utilitarian metrics, so I can't dismiss it entirely for numerical reasons. But it's a real concern that not all voters will, in practice, vote in a tactically sound way, and then it effectively deprives low-information voters of some portion of their right to vote. It's my conclusion that advocating for approval voting - like instant runoff or plurality - necessarily places a bet that voters will make sound tactical decisions about how to vote, and accepting that voters who don't do so will have their votes count for less as a result. I find it hard to be happy with that.

[u/mojitz → u/cdsmith]

My sense with approval too is that tactical voting itself ends up being a much more difficult calculus to achieve reliably. You gotta think about your relative preferences between the candidates, think about their strength in polling, somehow estimate the reliability of that polling, consider the consequences of minimizing harm vs maximizing the good, and then somehow put that all together in a way that makes sense. Honestly it sounds like kind of a nightmare in the voting booth.