As I did last year, I want to analyze the rushing stats for each team in 2014 using a metric known as Adjusted Rushing Yards per Carry. Thanks to the help of Brian Burke of Advanced Football Analytics (formerly Advanced NFL Stats), we were able to conclude that the value of a first down was about 9 yards. And since we’ve previously determined that the marginal value of a touchdown is 20 yards, this means Adjusted Rushing Yards per Carry is pretty easy to calculate. Also, since Bryan Frye crunched the numbers, we might as well exclude all kneels from the process, too.
One thing to keep in mind (which I have forgotten in the past): since the NFL records-keeping process labels touchdowns as first downs, you should only assign 11 yards per touchdown if you are already giving 9 yards to all 1st downs. And since kneels are marked down as runs, you must back those out, too. As a result, here’s the formula to use:
Adjusted Rushing Yards per Carry = (Rush Yards + 11 * Rush TDs + 9 * Rush First Downs – Kneel Yards Lost1 ) / (Rushes – Kneels)
If we use this metric to analyze the 2014 season, how would it look? Seattle was by far the top rushing team in the NFL last year, rushing for 2,762 yards and 20 touchdowns on 525 carries, good for a 5.26 yards per carry average. But 19 of those 525 carries were kneels, and they went for -20 yards. In addition, Seattle not only led the league with 144 rushing first downs, the Seahawks gained a first down on 28.5% of non-kneel carries, also the highest mark in the NFL. Seattle averaged 8.49 Adjusted Rushing Yards per Carry, while the NFL average was 6.63. Since the Seahawks averaged 1.86 ARY/C over average for 506 non-kneel carries, that means Seattle rushed for 941 rushing yards (1.86 * 506) above average.
The full list for all 2014 teams, below: [click to continue…]
- Since this is a negative number — i.e., 10 kneels for -11 yards — we need to subtract kneel yards to turn those yards into an add back in the numerator. [↩]