[dkarl]

Interviews aren't even like school exams at all. School exams are designed to try to ensure that you learn a certain set of material that was covered in a class. If you missed a bunch of it, that's bad. If at the same time you did independent research in a topic that wasn't covered in the class, it's not the business of an exam to discover that.

School exams are supposed to be fair, in the sense that they only cover the topics covered in class, and only to the level of detail and difficulty covered in the class. They test for weaknesses relative to that standard. When a school exam asks a question, it's because you're supposed to know the answer.

If someone takes the school exam definition of fairness into job interviews, they are going to feel terrified and aggrieved. Interviewers talk to candidates from vastly diverse backgrounds. Other candidates didn't go to your school, maybe didn't go to school in the same country as you, maybe didn't go to college at all. There is no fair, agreed-upon set of standard knowledge. If interviewers restrict themselves to "standard" topics, they will undervalue a lot of people who have unique backgrounds and experience. Not only that, but job interviews can't just measure a candidate's weaknesses against a set standard. It isn't even really a matter of "strengths" and "weaknesses" but wanting to discover a candidate's full capabilities. You don't want to miss a candidate's depth of knowledge in an area simply because you failed to ask any harder questions that would have revealed it. When an interviewer asks a surprising question, it's often not because you're supposed to know but because you might know and they don't want to undervalue you because they didn't ask.