Most organizations use a really flawed methodology to hire people in the first place (some combo of phone scree, behavioral, technical screen, team interview). Whether you know the area you're interviewing for or not... you aren't going to figure out if someone knows their shit in 3 hours of talking to them anyway because the only way to know for sure if someone can do something is to have them actually do that thing. Unfortunately most companies don't like this concept (this is not a reference to take home projects...)<p>Assuming you want to skip actually working with the prospect and you want to try to assess via an interview format, you're looking for one thing: Will this person help your company make money? I.E. will they get results.<p>While you can never answer that question for sure, looking for human beings that are results oriented is a reasonable first step. Machine Learning as an example is typically a project based type of work. Ask about their projects, how it went, and what was the result. If you talk to enough people about the results of their work, someone will stand out (maybe many people)... then you can move along to what normal hiring managers do anyway: hire who they like the most or pick out of a hat.<p>The other thing you can do is get expertise in the area.
Similar to how I'd interview someone who is smarter than me in my area of expertise.<p>Try to flip the roles. Treat the applicant like a consultant/mentor. Tell them about actual problems that you need solved. See how they solve them or improve on your solution. Compare between different applicants.<p>You'll want to look for clarity in their solution. Someone who overcomplicates their solution is probably bullshitting you. Someone who slows down and explains everything clearly probably understands what they're talking about. Like someone who says, "I would implement ABC here" and doesn't explain the advantages and disadvantages of ABC likely has weak knowledge.<p>With some of the smarter people I've worked with, they make no assumptions, and establish terms. "Are you familiar with ABC? No? Well, you know A? A is flawed for this solution because ___, and so we use ABC instead of A, even though ABC has this disadvantage over A."