There are many many metrics that are used by various analysts to describe and elucidate the play of those in football who throw the ball, run with the ball and catch the ball. There is also a dearth of metrics to describe the play of those who don’t.
For the offensive line (or anyone who is blocking on a play), how do you measure success? Is it a binary (+ for man you were blocking did not make tackle, - if he did) or are there degrees of success or failure on any given block? Additionally how are we to know what was the assignment for a given blocker on a given play?