Supervisors wrote glowing feedback in order to avoid having to deliver unpleasant messages, and to avoid creating a paper trail that might undermine their own ability to fight for their employees in the actual ranking meeting.
Similarly, I used to see various 360 degree feedback tools that operated in the same way. These tended to have a bi-modal distribution. Someone who hated your guts for some reason would give you low ratings, but most people, knowing these factored into performance evaluations, tended to give very high marks even for upward feedback.
So how do you structure something that gets you real, useful feedback?
