I definitely wouldn't call myself an expert, but in my career I've probably interviewed a few hundred people. I think people way over-complicate this stuff by trying to be too clever.
To me, the most useful question is this: "here is an example project that we'd be likely to do, how would you build it?" Then you just let them walk through the steps they'd take.
From there you can launch into why they made the choices they made, trade-offs, philosophy, etc. When you hear people explain how they would make something real, you start to learn a lot of things about them without even needing to ask, and so you're less likely to get scripted answers. They're also probably in their comfort zone at this point, so you get to see them in a more real way.
I don't necessarily mind "homework" style projects, but I tend to shy away from that sort of thing as it's not always respectful of the candidates time.
Two questions I usually avoid (but see getting asked all the time): puzzle questions, and language trivia. I don't ask puzzle questions because I've never seen it correlate to something useful. Most puzzles require an "aha" moment where your subconscious bubbles up some kind of answer, but the easiest way to short circuit that part of a persons brain is to put them in front of strangers with a time constraint. Puzzles might give you a clue as to a persons overall IQ and confidence, but it won't tell you a lot about how they can do the job.
Puzzle questions are also "expensive", in that they usually put a candidate on edge, and they set off the candidates bullshit detector. Let's keep in mind that we're going to reject the majority of candidates, statistically speaking, but you still want them to think highly of your company. If they feel like they're being rejected for a BS reason, you've just created animosity towards your company. It's important that the people you reject still feel respected.
I don't ask language or framework trivia, as I don't think it's useful. I might lob a softball about a framework just to make sure they've actually used it, but I'm not going to ask something hard.
I always have turned down homework assignments. It just feels insulting and disrespectful. Even whiteboard crap is useless but I'm OK with it considering they've paid for my travel expenses etc.
If you think about it ... homework assignments are a classic case of B's looking for C's. A's wouldn't need to resort to such silliness. They can identify (as an interviewer) and exhibit (as an A interviewee) with just an intelligent conversation.
To me, the most useful question is this: "here is an example project that we'd be likely to do, how would you build it?" Then you just let them walk through the steps they'd take.
From there you can launch into why they made the choices they made, trade-offs, philosophy, etc. When you hear people explain how they would make something real, you start to learn a lot of things about them without even needing to ask, and so you're less likely to get scripted answers. They're also probably in their comfort zone at this point, so you get to see them in a more real way.
I don't necessarily mind "homework" style projects, but I tend to shy away from that sort of thing as it's not always respectful of the candidates time.
Two questions I usually avoid (but see getting asked all the time): puzzle questions, and language trivia. I don't ask puzzle questions because I've never seen it correlate to something useful. Most puzzles require an "aha" moment where your subconscious bubbles up some kind of answer, but the easiest way to short circuit that part of a persons brain is to put them in front of strangers with a time constraint. Puzzles might give you a clue as to a persons overall IQ and confidence, but it won't tell you a lot about how they can do the job.
Puzzle questions are also "expensive", in that they usually put a candidate on edge, and they set off the candidates bullshit detector. Let's keep in mind that we're going to reject the majority of candidates, statistically speaking, but you still want them to think highly of your company. If they feel like they're being rejected for a BS reason, you've just created animosity towards your company. It's important that the people you reject still feel respected.
I don't ask language or framework trivia, as I don't think it's useful. I might lob a softball about a framework just to make sure they've actually used it, but I'm not going to ask something hard.