No one is doubting the risk mitigation, which is why the process exists in first place. But the BS of wasting someones time also needs to be addressed. The reason most companies waste peoples time is because they are too busy with abstract concepts tangentally related to the actual job, and theoretical models by some "expert" of HR management. Software engineering has become a psuedo-religious exercise in computing witchcraft.

If you want a backend engineer - book a few hours, even on a weekend, set up an IDE and get on a real world project. No bullshit. Build a small API to these requirements, using these technologies but take care of edge cases and deploy that bad boy.

Are you (or they) suggesting that the 4th interview meaningfully reduces the number of bad hires?

I’m guessing not.

It’s poorly designed and/or poorly implemented hiring strategies that lead to bad hires, mostly through a lot of noise being collected during the interview process.

This is a very solvable problem.

Edit: I will add that this is an ad for Booz hiring, so of course they want more process.

6 interviews increase the chances of a bad hire (or at least decreases the chances of a great one). It restricts your hiring pool to those who are willing to be abused by the company. That's not the top-tier talent.

That’s quite the range. It suggests a strategy: worry less about hiring false positives (with all the concomitant issues not hiring anyone brings) and worry more about reducing the cost of those false positives.