FO Mailbag: "Team-Adjusted" Run Stop Rates

Tuluse: I was reading through the comments for the article on Run Stop Rate, and realized that it's a flawed stat because it doesn't take into account a player completely whiffing a tackle. I know you have other stats to try to account for this based on the charting project. However, I wonder if you would indulge me and post a stop rate based on the total number of runs a team faced. Getting 20 stops is a lot more impressive on a good run defense that doesn't see many runs vs the Bears for example where teams were running whenever and however they could.

I know this would be a flawed stat as well because it doesn't account for plays when the player is not on the field, but you could adjust for games where the player actually played and maybe even use the participation data (if a defender plays for 80 percent of snaps and the team faced 20 runs, assume they were on the field for 16 runs). I know it's not perfect, but football stats never are and it would be interesting to see.

I've actually been sitting on this a while. Suddenly got the urge to answer it today, perhaps because I'm excited to finally be done with broken tackle stats, which will run sometime in the next couple weeks and sort of tie into the idea here.

We'll run these quick, so not a lot of commentary from me. I'll let the readers provide commentary by comparing these numbers to the Run Stop Rate numbers I ran a few weeks ago, which again are here.

I started here with each player's percentage of defensive snaps by dividing defensive snaps by the number of defensive plays his team faced only in games where he was active. Then we multiply that number by the number of runs a team faced (including scrambles, but not including kneeldowns). That gives us the estimated number of runs when each player was on the field. I used that to create two stats. Adjusted Percent of Team Run Plays divides a player's total run tackles (including assists) by that estimated number of runs faced. Adjusted Run Stop Rate divides a player's run Stops (plays that prevent a successful offensive gain) by that estimated number of runs faced.

We're going to get very different lists here because now we are more measuring how many plays a defender was involved in rather than how often he made a successful tackle. But there are differences. For example, the list of the top linebackers shows how strong Lavonte David was against the run this year.

With the defensive linemen, you get a good idea once againg of how awesome J.J. Watt is, but also how important the defensive ends were to the run defenses for the Jets and Patriots.

Things get more interesting with defensive backs. With linebackers and defensive linemen, the leaders in "Adj Pct Team Run Plays" were basically the same as the leaders in "Adj Run Stop Rate," just in a different order. However, because a lot of defensive backs are stuck making clean-up tackles, you get some real differences with cornerbacks and safeties. I've taken these top tens and added (in italics) a couple of players who made a huge number of run plays for their teams but didn't make a lot of run Stops because those plays were so far downfield.

I have no idea why Josh Wilson played such a huge role in the Washington run defense this year, and why he made his plays so much closer to the line of scrimmage than DeAngelo Hall.

I think I counted Mathieu as a safety when I originally ran Run Stop Rates. Now we've decided to mark him as a cornerback. It's hard to put him in one place or the other, because he played so much of both. But with almost every offense in the NFL now using three or more wide receivers on a majority of plays, I figure he's more a nickelback than a free safety.