> In other words, the difference between a psychological evaluation of an individual and that individual's potential to do this sort of work becomes very muddy

> In other words, the difference between a psychological evaluation of an individual and that individual's potential to do this sort of work becomes very muddy and indistinct. You want to have a picture of their psychology, because the problems you're hiring them for are often psychological in nature. That might be true but if it’s important then it should be conducted by a trained psychologist, not some random hiring manager.