I already don't want the job because of the interview process. Talking to someone about code they have written and the decisions and thinking around their own code is so much more respectful and gives better signal. You should be doing everything you can to put the candidate on their own turf and letting them shine. I have a lot of advice about interviews but one of the best I've heard over the years: whatever impression you have of the candidate try to prove yourself wrong. Using that advice, I've found a lot of great programmers that other companies skip over. Some people who are great at coding are bad at interviews and bad at live problem solving with an audience. If you really feel the need for a test, a paid take home coding assignment will give you the best signal.