This is why I hate every big company in the US.
THIS SHIT. Employee "ratings". Usually yearly ones to determine your pay/raise/bonus for the year. It's utter bullshit.
Theoretically, it is VERY much possible for EVERYONE to be working at an equal (or close to equal) rate. So everyone could be working like complete shitbags (*Cough*Any Government Jobs*Cough*), or everyone could be working at 110%. Well, that doesn't matter, because the company has a simple logic of: "We have 70% lvl 3's to give out, 10% lvl 2/4's to give out, and 5% lvl 1/5's to give out".