More than a decade ago, PFF was founded on proving or disproving general perceptions of players through an unmatched level of detail—unbiased grading of every player on every play of every game. Does the guard who’s made the Pro Bowl five straight seasons still deserve the honor? Did the league’s sack leader generate a lot of pressures quickly, or were some sacks simply cleanups or unblocked?
The truth is, box-score statistics and previous biases can have an immense impact on our notions of how productive a player was. For the defensive side of the ball (or offensive line), this point is emphasized further, since tackles and sacks are commonly used to judge performance.