My wife had a system at the last place she worked and I found that it was very interesting how different sections weighted the value given differently. What was also interesting was where you rate yourself, then your boss rates you, then HR rates you. If you have a 4 you can get a raise and less than that, any raise had to be justified.
Just before they started the layoffs, my wife (19 years with the company) went from 5 to 3- from one review to the next. Set her up to be let go in a heart beat.
So, with that being said ... PHB would be black mold snowcones on a blunt object?