Good points. In the 3rd edition of Topgrading I offer definitions of A, B, C across many competencies, but early in the book I say that the simplest way to think of A, B, C Players is high performer, adequate, low performer. I've asked 6,500 executives (in Topgrading Interviews) to characterize the teams they inherited and ended up with and they easily relate to high perfumer, adequate, low performer ... and the long explanation of "top 10%% can be avoided. These 3 categories work for executives or part time stockers. That said, over time companies get better and better "calibrated" and the requirements become stiffer; therefore, in 2014 clients think back to their designations 3 years ago and now put a higher percentage in the lower categories ... because is does take time/experience to accurately rate someone. Hope this helps!