[shock]

I've done several approaches:

- homework project

- heavy interviewing with plenty of tests and several (3-6 people) giving written feedback on the candidate in the form of 5 points rating on lots of skills

- hire on gut feeling

mixed in various amounts.

In my case, a diploma/certificate doesn't make me feel better. I've seen plenty of incompetents with a diploma, so I don't take it at face value. Testing worked best for me. A diploma/certificate also doesn't tell you anything about the candidate's work style/attitude. A hire with a bad attitude is much more toxic than a hire that lacks technical skills.