Any scheme at all is always going to be vulnerable to false negatives. There are companies that have multiple-stage recruitment, with skill tests, psychometric tests, multi-person interviews, background checking - and still end up with a few duds.

But if you can use a bunch of proxies (like StackOverflow, GitHub, and LinkedIn), and know the value of each of those proxies, then you can more efficiently match a person with a role. Sure, there'll be lots of mistakes, but it's hard to see a better alternative.