These two below resonate after hiring dozens of engineers:
> – What kind of quality work does this person produce in a normal work environment where someone isn’t breathing down their neck?
> – Can I work with this person on projects that span weeks, months, or years?
No matter how well they anwser questions, how they whiteboard, how high is their IQ, or how well they do homework - none of it would tell you anything about their work quality or actual on the job performance.
Just ask them a for loop question and give them a contract to work on something. If it works, maybe hire them.