Something i've seen a couple of times is giving a take-home exercise, then working on it further in the on-site interview. The first stage filters out people wh

Something i've seen a couple of times is giving a take-home exercise, then working on it further in the on-site interview. The first stage filters out people who can't get things done even given as much time and help as they want, the second stage filters out people who can't get things done at a reasonable pace without a helping hand. I think it's common for an on-site interview to include a reasonable chunk of programming, and using a continuation of the take-home to do that is good because it means the candidate isn't starting from scratch. Coming in warmed up should minimise noise from nerves, unfamiliarity with tools or context, etc.