[gdiamos]

I personally hire people I’ve worked with before and I know what they can do.

If I can’t do that, I ask to see their prior work.

Good programmers have usually written a lot of code. Having them walk through and explain it usually gives a good idea of what they can do and how they think.

Sometimes you meet a programmer who only works on proprietary code and can’t share it.

In that case I ask them to explain the design of something similar, and write a modestly sized example of a component of that system. Watching them in their own dev environment for 30 minutes usually tells you all you need to know.