Think about it this way: no matter how low you put the dividing line between A-level and B-level performers, you will always have people that fall below the lin

Think about it this way: no matter how low you put the dividing line between A-level and B-level performers, you will always have people that fall below the line. So, set your line appropriately, but fire people below the line, no matter how "hard" they work / how much time they spend "ass-in-chair".