As an employee, I want to be treated fairly. I don’t mind someone being paid more than me if they are contributing more. But if we’re doing the same work and they’re being paid way more, I’ll be mighty unhappy. A just rating system means I don’t have to worry about that. It also means that if someone does exceptional work, they’ll be seen not just by their manager, but by lots of managers in the calibration meeting, who together create and promulgate a consistent standard across the company. Ratings also make it easier for people to move across the company.