"Can you tell me about a hard problem you've solved?" is usually enough to kick off a good dialogue. It gives you a little peek into their approach to solving p

"Can you tell me about a hard problem you've solved?" is usually enough to kick off a good dialogue. It gives you a little peek into their approach to solving problems, but also tells you what they think is hard. If you ask good follow up questions, you'll very quickly have a solid understanding of their current experience levels and a rough gauge of their aptitude. A lot of it comes from intuition and experience interviewing and hiring. Building out a great team is more art than science, and you won't ever hone that craft by throwing coding challenges at your applicants - you just end up with a group of people who are a bit more likely to be very good at jumping through arbitrary hoops.