Tony quotes Weinberg.

Under a performance appraisal system, placating or irrelevant managers can think, ‘Well, I won’t bring that up right now. I’ll save it for the performance appraisal in December.’

Before I gave my first performance appraisals I asked my boss if he had any suggestions as to how these should be run. He said, “Nothing that is said at an appraisal should surprise the person who is being appraised”. Good advice.