[pillowkusis]

I suspect HR does gating because it works. HR’s goal is to fill the interview pipeline with as many “reasonable” candidates as possible. They can’t spend much time looking at each candidate since there’s so many. But if it sends down an obviously bad candidate, they’ll get yelled at. HR Gating is applying some naive statistical thinking. 80% of our employees have trait X. Therefore by filtering for trait X we increase the odds of sending reasonable candidates down the pipe. Filter by enough traits, and you’ll be sending only “reasonable” candidates through to the next stage. Cheap and rarely obviously wrong.

The problem, of course, is that trait X could be anything. Technology, trivia, personality, Microsoft Excel Whiz, X years of experience, Causation, correlation, it doesn’t matter. “Reasonable” does not mean “fair” or “logical” or “causative.” It’s just a statistical trick.

I suspect that the “CS Trivia Interview” is just a more nuanced version of this. Knowing now to invert a binary tree doesn’t make you a better programmer (no causation). But many good programmers happen to know how to do it (or want the job enough to learn it just to please you). So it’s an easier metric than trying to define what “good engineer” means.