Hiring managers have a real problem to solve: “how do I hire?”. They don’t have the time to conduct actual experiments and work out what actually relates to better hiring. So they trivialise the solution into some assumption about how the information captured in an interview generalises to overall suitability. They then proceed to defend the process and it’s results as if it was state of the art because bad hiring = bad management in the politics game.
To me it feels obvious that whiteboards, pair programming , take home tasks, panel interviews , etc are all subject to being highly flakey and highly presumptive not least because repeatable processes are just hard to enforce and train people on.
What really works is survival. Practically every company has a probationary period but it’s rare that once you’re in you’ll get bounced out in my experience. IMO bite the bullet, over hire and then collect the cream based on evaluation of the total output and the teams impressions in the probationary period ...