I saw that first hand, and the moral boost for the 20% that get higher than average raises -almost- offsets the fear of being in the 10% that get put on mandatory performance plan. it can be a game where you take one for the team, get on the 10% performance plan and get off it before the next review cycle. if you get put on twice in a row you are out, so at times you can game the system by trading who goes into the 10% bucket.

see GE share holder notes from 2000 http://www.ge.com/annual00/letter/page4.html