It’s difficult to measure performance even in the abstract. Every person in the company is a node in the network and even if a person’s objective metrics are lower than another’s, it could be that removing that node destroys institutional knowledge that causes everyone else’s performance to drop.

And as far as objective metrics, those are a crapshoot too. See: the software interview process, where people memorize useless toy problems into their brain so they look prepared for performative problem solving.