Earlier quoted context omitted.
I think grading people to a standard is very difficult. At the last place I worked I was managing people and we were given a set of "standards" to rate employees on, used to determine raises, promotions, and so on. I tried my best fairly evaluate my reports, but obviously the standards are inherently imprecise and so the evaluations are mostly qualitative. I found that other managers, wanting to do well by their repo…
Promotions are always going to be subjective because they're a judgement call about how well the person will perform in a more senior role. Firing someone is different; the bar for that is that they are squarely underperforming relative to what is reasonably expectable. The idea that some fixed percentage of people always underperform is possibly Jack Welch's most toxic contribution to management, and with all the BS…
There is also the more philosophical question of where that standard would come from in the first place. And what if the business finds that the average applicant meets a much higher standard than the current firing standard of the company? It would seem to then make sense to raise the company's own firing standard.