How good a rater do you think you are? If you were my manager and you watched my performance for an entire year, how accurate do you think your ratings of me would be on attributes such as my “promotability” or “potential?”
How about more specific attributes such as my customer focus or my learning agility? Do you think that you’re one of those people who, with enough time spent observing me, could reliably rate these aspects of my performance on a 1-to-5 scale? And how about the people around you – your peers, direct reports, or your boss? Do you think that with enough training they could become reliable raters of you?
These are critically important questions, because in the grand majority of organizations we operate as though the answer to all of them is yes, with enough training and time, people can become reliable raters of other people. And on this answer we have constructed our entire edifice of HR systems and processes. When we ask your boss to rate you on “potential” and to put this rating into a nine-box performance-potential grid, we do it because we assume that your boss’s rating is a valid measure of your “potential”— something we can then compare to his (and other managers’) ratings of your peers’ “potential” and decide which of you should be promoted.