Ask HN: How much of your hiring practice and/or decisions are made from testing?

I don't think anyone underestimates the value of testing candidates to separate wheat from the chaff when finding a candidate to hire into your team. This question just comes from observation and anecdote (with a healthy dose of curiosity on the side), but one of the things I think you can't test-or at the very least test using something other than a computer-is compatibility. The intangibles: communication, attitude, spirit et al yet I've seen so many products popping up to test developers and administrators with coding challenges and exercises.

That prompts me to ask the question in the title: How much of your hiring practices is influenced by test results? Let's go further, how often do you test internally to improve your staff, as well as acquire new talent? Do you see it as adding value? One additional layer of complexity? Have you seen a decrease in candidates but an increase in quality resumes?

Thanks, and happy holidays-whatever you're celebrating!