[jsweojtj]

It happens all the time, and it comes from a mix of things.

One way it happens is that you get a PhD in astrophysics with years of data analysis experience in for a data science job. Have a software engineer interview her and he might find that she doesn't know a number of basic computer sciences concepts [traversing a linked list, tail recursion, implement breadth-first-search]. His knowledge background says these basic ideas are fundamental, there are therefore serious questions about the technical ability of the interviewee.

[raverbashing]

This is a good example. At the same time this CS interviewer may not know what's the second central moment of a probability density function.

[eli_gottlieb]

Uhhh... the variance?