There is a lot of anecdotes in the comments about these interview processes. The ones with the best data are the company themselves, especially those who interview thousands of candidates a year. These companies (e.g., all FANG) have enough data to assess which interviewer, which interview questions and which interview process have positive correlation (and even causation) with future employee performance. And they c…
Say that I wanted to sort men from women to only identify women. One thing I could do is have the candidate walk under a bar that was 5 foot 4.
Most of the people who would get through would be women. But this would not be an efficient screening method. I would still be losing many women to the screening method.
If I am only polling the women who get to the end of the screening to see if they are women, I can't evaluate the efficacy of the screening. Facebook/Google would need to hire some of the failed candidates to compare results.