I've been looking at run Success Rate (SR) lately, and it appears to be a fairly important indicator of team success. But if I said that a particular team's run SR was 45%, how would you know if that's any good? It's less than 50%, so does that mean it's bad? So I decided to plot Expected Points Added (EPA) against SR to find out where the break-even point is.
When I plot run EPA per play vs. run SR (for 2000 through 2009), the break-even point is where the best-fit line crosses EPA/P axis--just above 41%.
But remember that run SR correlates with passing success too. When we consider both play types, it appears that a team needs just over a 39% run SR to have a net positive EPA per play.
When I did the same thing with WPA vs. run SR, I got the same break-even values.
Who are the leaders so far in offensive run SR in 2010? NE is way out in front with 52.3%. OAK, HST, DAL, PHI, and JAX make up the second tier, ranging from 49 to 47% (through Sunday afternoon).
What about defenses? Atlanta tops the list with a 69.9% defensive run SR (offenses are successful only 31.1% of the time). SEA, BLT, and NYG are right behind.
To see the full lists, just visit the advanced team stat page and sort by run SR column. SR for running backs (and other positions) is available on the individual stat pages.