I have worked with several colleges on advanced stats and have used them on the high school/pee-wee/college levels. I have thought about yards after contact for receivers but I don't understand how to maintain an evenness across the board to gain a meaningful stat.
For instance yards after catch is not subjective. Boom where did the ball hit his hands and how far did he go. But even this stat tells almost nothing. Runningbacks have the most YAC because they generally catch the ball even or behind the line (for the most part) and they obviously gain yards. WRs who are the leaderboards generally focus on quick slants and bubble screens. Are they a "better" receiver or more dynamic because of this? Hmmm. Maybe. By how much? Not sure.
Is the high yards after catch a byproduct of teams worried about deeper routes, is it because of superior edge blocking, is it because this receiver can't run his route tree correct so the coach only trusts him with short stuff and streaks?
Now take your stat which in a well defined lab would probably give decent analysis but first of all how do we define contact? It is very very subjective and you would need the same person (or cloned people) to evaluate all of the film. If a defender's shoulder pads brush against a WR as they try to jump a hitch contact? Is a defender hand on the back (which unless the WR is wide open is almost a norm in the NFL now) contact? Is a fist coming down trying to strip the ball contact? If a receiver catches a screen and jukes the CB that is less than a yard away is that contact (and said CB makes no contact)?
There would have to be 50 "rules" in place to get this stat. I would say that a first rule would be that contact includes any defender making contact in a tackling motion (no matter how pathetic the motion is since most NFL DBs can't tackle) or a defender in very close proximity (where an immediate tackle would be the norm) is juked/side-stepped.
This stat I am sure would have some sort of relevance to how well a QB throws into tight spaces and I am sure the big name QBs would have WRs near the top of the list (because those guys have the most yards). However a couple problems off the top of my head.
- by focusing on contact you are dissing the WR that consistently gets open and creates space. They probably aren't contacted until tackled.
- to go along with the first point a defender will be more apt to take chances and break on a ball if they are close to it. Obviously a defender isn't going for an interception and breaking towards the QB if there guy has them beat by 5 yards. But if he is running stride for stride he might. Also if the QB throws the ball behind the WR he might. Both of the circumstances often causes contact. Both of them are negative things that would reflect positively in your stat.
- you are really negating the guys who are consistent deep threats. If you beat a defender long there usually isn't contact. It might happen but not as consistently.
If this stat exists in any form it would be done by Football Outsiders or KC Joyner's team. I am a regular on both of their sites and it doesn't exist in your form. Is your stat relevant? I am not sure because of the problems outlined above. I think the first step is maybe getting 50-100 games and break down the yards after contact for WRs based on field metrics. For example split them into 0-5 yards, 6-15 yards, 16-25 yards, and 25+ yards. Also you are going to have to do something about TDs. If Randy Moss jumps up for a 50 yard bomb and catches it at the 5 yard line with two defenders hanging on him, he shoves one down, and walks in the end zone... he gets 5 yards?