Once again, FootballOutsiders has lended itself to SB Nation, answering five questions from each blog about their team. These questions and answers should slant towards the advanced analytics that FO focuses on, specifically in regards to DVOA. To find out more about the great work at FootballOutsiders, you should definitely be keen on their annual almanac, which is available now in the FO Store.
Today, we’re looking at how advanced analytics could better serve the evaluation of offensive linemen.
Q: From our writer John Fraley: “Do you have designs on exploring advanced OL stats beyond adjusted line yards? Or is that a fool’s errand?”
Bryan Knowles: I wouldn’t call it a fool’s errand, but it’s very difficult. We have a number of stats measuring offensive line play – adjusted line yards, adjusted sack rate, pressure rate, stuffed percentage, power success and so on – but it’s all sort of only covering the offensive line in a reflective sense. Skill position players are easy – so and so passes the ball, so and so catches it, so and so runs off-tackle – but how much credit do you give the line for each play, and how do you separate that from overall team success? That’s a real challenge, even before you start to think about crediting individual linemen.
We’ll likely never have DVOA or DYAR for linemen, because any useful rating system for linemen has to include subjective factors. We keep track of these things – our partners at Sports Info Solutions chart blown blocks on both the individual and team levels, and try to credit sacks to individual linemen – but without knowing the actual blocking assignments on each play, many of these decisions are going to be judgment calls. Which lineman was responsible for the lineman who split the A-gap; did the left tackle blow his block or did the quarterback hold the ball for too long, and so on and so forth. The nice thing about DYAR and DVOA is that it’s objective – play X gained Y% more yards than average against a defense that is Z% better than average. While we tinker and work with the system in the offseason to make it more predictive, we’re not assigning subjective qualities to each play and presenting it as a final rating. We prefer to let the rating speak for itself, and then write about more subjective and charting elements that help interpret the numbers (see our annual adjusted interception article, for one). That’s not really possible to do for offensive linemen with the data we currently have, and so we’re it’s unlikely that we’ll roll out a new rating system in the near future.
That being said, the data is always improving. We have a new partnership with EdjSports which gives us some more tools to use, and the NFL’s Next Gen Stats are providing more and more interesting stuff each year. I doubt we’ll have an offensive lineman-specific stat in the near future, but we may be able to provide more splits – which teams run best with a pulling guard, or which linemen get extra blocking help from tight ends on a regular basis. We’re always looking to provide new things!