You need to ask questions that you can solve in something like a quarter of the time you're allocating for the interviewee, not just the same time. Even if you'

You need to ask questions that you can solve in something like a quarter of the time you're allocating for the interviewee, not just the same time. Even if you're interviewing someone with your exact skill set and domain knowledge (and you aren't) there's just a bunch of inherent overhead in presenting someone else with a problem to solve.