General Electric Corp. (Fairfield, CT) uses as a "20-70-10 plan" that identifies the top 20 percent, the middle 70 percent and the bottom 10 percent of its managerial and professional employees. It's not unusual for the top 20 percent and the middle 70 percent to trade places often. However, the bottom 10 percent tend to remain there and eventually get forced out of the company.
Ford Motor Co. (Dearborn, MI) recently dropped a very subjective program that assigned all managers an A, B or C grade. The "Performance Management Practice" divided employees into groups of 30 to 50. From each group, 10 percent received an A, 80 percent got a B and 10 percent earned a C.