> Unlike many single-winner methods, instant-runoff cannot accept equal rankings, and must discard ballots with multiple first-preferred remaining alternatives: such ballots would be equivalent to casting multiple ballots in a plurality election
With all-the hubbub on the last election about vote validity, and hanging chads before that, the last thing we need is screw-up-able ballots.
IMHO we should not even consider any methods in which you can violate invariants on a paper ballot. That rules out FPTP, IRV, and any others where the user with pen-and-paper can enter an invalid state.
Err, I guess that rules out 321, which is my new favorite. Simple fix: just count multi Bad/Ok/Good entries toward that total. In the first round, you only look at "good" scores, ignoring ok/bad. Then in the bad round, same thing. This ensures a) you can't produce a bad ballot b) ballot counts stay orthogonal for each category c) multi-entries kinda average out.
E2: well I guess you can manage to screw up ANY style of paper ballot and violate some invariant. I guess it matters the difficulty of screwing it up and whether it's recoverable.
I agree that a likelihood of higher-than-normal percentage of spoiled ballots is a potential problem with IRV, at least with mail-in or in-person paper ballots. Voting machines shouldn't have a problem with it.
Approval is about as simple as it gets. In order to spoil the ballot you'd have to do something pretty strange like tear the ballot in half. Or with mail-in ballots, the usual things like not signing the envelope (assuming that's required in your state) or mailing it too late to arrive on time.
I don't see ballot spoiling as necessarily a show-stopper for using RCV on its own, but there are other compelling reasons not to use it (such as failing monotonicity).
And you've always been able to produce invalid ballots, like voting for two candidates when you're only allowed to pick one.
You're describing a UX problem which has UX solutions. It's not even remotely a justification for selecting a democratic procedure to express the will of the people.
Agreed but that's far from my only gripe with FPTP and IRV.
The main proponent of approval voting seems to be the Center for Election Science, which is a pretty small organization, though I think they've gotten a little bigger over the last few years. There's also some STAR voting groups. None of these groups have huge piles of money to spend.
Then there's news organizations (including the NPR story posted here on HN today) promoting RCV/IRV.
On its face, IRV seems pretty straightforward and reasonable. It's problems are complicated and hard to describe. The examples of non-monotonic results where voters can cause their preferred candidate to lose by ranking them too highly are counterintuitive and hard to follow, and I wouldn't blame anyone for thinking: "What? that doesn't make sense. You must have made a mistake somewhere..."
There's also the common sentiments of "this is an emergency we need to fix right now" and "everyone's already on the RCV bandwagon" and "replacing a broken system with a half-broken system is usually politically more feasible than replacing a broken system with a not-broken system" and "don't let the perfect be the enemy of the good" and so on.
There are also criticisms of the other voting systems. Some people are bothered by approval voting's lack of ordered preferences, for instance, and score voting is susceptible to strategic voting where the most extreme rankings have the most influence. STAR voting mitigates that to some extent, but it's not perfect.
I worry that we'll replace FPTP with IRV, find out later that it didn't live up to expectations, and then when voting reform advocates start pushing for something better like approval voting or STAR, the voters will say, "why should we believe you when a bunch of voting reform advocates promised unicorns and rainbows and we got a system that doesn't work any better than FPTP?" And then they'll either say to heck with all this voting theory nonsense and go back to FPTP or just live with IRV. And that's optimistically assuming that our future selves don't just abandon democracy itself as an unworkable idea (and though I reject that premise I have to concede that there's no lack of evidence pointing in that direction).