How do you know what level to pitch the interview at if you don't know what language features someone understands and how they code?

Where I work we now set a small simple test which is very representative of what colleagues do because we've had so many time wasters. I'm looking to see their style, the fact that they can actually read a simple spec (apparently over half can't), and that they can explain why they approached the solution how they did. If their test is no good, we don't waste each others' time.

If someone has a decent GH account I'll look at that too - if it's sufficiently comprehensive (very rare to see anyone with a GH account at all, let alone their own projects in it) they won't need to do the homework (should take about an hour, less if they're good). This just saves us wasted time.

Remember - you might know you're good. How do you expect strangers to?