"For while anyone can sit back and point to the bottom line as justification, assessing instead a person's actual knowledge and actual ability takes confidence, thought, good judgement, and, well, guts. You can't just stand up in a meeting with your colleagues and yell, "Don't fire her. She was just on the wrong end of a Bernoulli series." Nor is it likely to win you friends if you stand up and say of the gloating fellow who just sold more Toyota Camrys than anyone else in the history of the dealership, "It was just a random fluctuation."