Are you saying each interviewer just makes up their own questions?! That's ludicrous if so. Where I work, we have a standardized pool, with standardized evaluation criteria.
Everyone makes up their own. I can't for the life of me fathom how this doesn't subject them to all sorts of discrimination etc. claims (one of the reasons lots of companies favour standardised questions).
Obviously the drawback for FAANG is that standardised questions would rather rapidly leak. Very quickly you'll just end up with candidates that know how to answer your questions.
Where I work now, it's a mix of pool questions ("soft" skills) and interviewer-made questions (technical skills), but it's not a hard and fast rule to use the pool questions. I rarely use the precise wording for the pool questions, and instead adapt them to match the conversation with the candidate.
Adapting to the candidate is probably good most of the time, but don't work too hard to make that happen. Computational geometry is on my resume, and interviewers are always trying to show that they know that too by trying to bend their question into that. The exercise very often detours as they've led me way down a wrong path because they're analogy doesn't fit, and all they wanted to know was if I knew about minimum spanning trees or even just heaps.
Are you saying each interviewer just makes up their own questions?! That's ludicrous if so. Where I work, we have a standardized pool, with standardized evaluation criteria.