>2-8% of rape complaints are false

Complaints is the key here. Obviously, we can't say much about the incidents that don't go reported. If one looks at the conviction rate for rape complaints it's around 2%. So if we take the lower estimate for false complaints, it still means that only 4% of cases are provable one way or the other, and that those which are have a 50/50 chance of being true or false complaints. (I'm looking at '92 stats, at a glance it appears the the rates for both rape and false rape convictions have risen a fair bit since then).

Interestingly, a 2% conviction rate is on par with that of robbery.

https://blogs.findlaw.com/blotter/2017/07/how-often-do-rape-...