[boomka]

That is the truth that is often overlooked.

Feedback is not entirely useless, but good managers know that how useful a person ends up being, is not a function of his knowledge at the time of the interview. And that is true even for highly skilled professions like programming.

Performance/productivity is dominated by human factors, psychological factors, office environment, team synergy etc etc.

Even when I do technical interviews, people assume I am interested in getting the right answers out of them. In truth, while I am somewhat interested in what answer they give, I mostly watch _how_ they answer the questions.