We have all had our unique experiences with performance Management systems...and who has not experienced meeting the classic bete-noire in our companies, the one who actually being under skilled and thus low in performance, rates himself the highest on his skills and blames the Manager & his perpetual bias for under-rating him ? The Dunning-Kruger effect offers an explanation on critical errors in self ratings. It establishes that the least skilled 25% performers generally scored well above the average and had no idea of how little they knew. Expectations of the middle 25% were both more modest and more accurate than the bottom 25%. The most accomplished 25% tended to slightly underestimate their own abilities !!! Your Manager does not always have a bias or hates you as it may seem to be the script of all those who may not be highly skilled. Sometimes ones lack of understanding of what the full scale performance is all about that causes the discrepancy. Thus train and upskill your people to understand what the full scale performance looks like. They will then tend to be more self-critical and accept their Manager's rating without debating much ( or so I believe).