Here's a stat you probably didn't know: this year's Eagles offense is on pace to register one of the smallest three-and-out percentages in recent history. Through six games, Football Outsiders clocks the Eagles as having three-and-outs on only 10.8% of all drives. If they can keep that pace up, it would tie them for second-best among all teams over the last 16 years (the entire period FO has accounted for this stat).
There are a number of things that help Chip Kelly's offense avoid the dreaded three-and-out. Part is just being tremendously efficient across the board. The historical team the Eagles are tied with right now is the 2001 St. Louis Rams, an offensive juggernaut that rode to a 14-2 record and Super Bowl appearance. Like those Rams, the 2013 Eagles rank second overall in offensive DVOA, with both passing and rushing offenses in the top 5. When you register a full 1.2 yards more per play than the average NFL offense, you're going to have fewer dead drives.
But that's not all. The number two ranked team in three-and-out percentage is the Carolina Panthers, and their offense is middling. There's another key to Kelly's success in this area, and it's relatively simple: he runs the ball more on third down and short.
On third down with 1 or 2 yards to go, NFL teams run just slightly more than they pass this year: 52%. This is odd, because running is significantly more effective. 66% of all runs from this distance convert a first down, while only 51% of passes do. Such odds would be even more favorable for the Eagles offense. The offensive line has looked good so far (although only 3.81 adjusted line yards), but more importantly LeSean McCoy is a beast. Kelly clearly knows this. He has called run plays in those situations 84% of the time, far more than any other team -- and has an 81% success rate to show for them.
The tendency extends to third downs from 3 to 5 yards out as well. For most NFL offenses, this is a straight passing down. A quarter of teams have yet to call a run in this situation, and the overall rush rate is a measly 10%. This seems to be a rational decision for most teams. At this run-pass ratio, the success rate for both has hit an equilibrium of about 47%.
Kelly, however, has called runs on 35% of these plays. That percentage is exceeded by only one other team: the Panthers, who we mentioned above. Both teams have succeeded with this strategy. The Panthers, with Cam Newton and a couple of successful backs, have been successful on 60% of their runs. The Eagles have converted a first down on over 70% of such plays.
This isn't new territory. Brian Burke wrote about how NFL teams should run more on third and short back in 2008:
On 3rd and 1, offenses scored an average of 2.38 points if they ran, and an average of 2.24 points if they passed. The difference of 0.14 points is remarkably close to the 0.12-point theoretical estimate calculated above.
The differences are even bigger for 3rd and 2 and 3rd and 3 situations. The advantage of running is 0.45 and 0.31 expected points respectively—convincing evidence that offenses should be running more often on 3rd and short.
With the numbers -- and an elite back -- to support him, Kelly's play calling has been spot on. The Eagles have converted 74% of all third downs from 1-5 yards. That's the highest rate in the league, and is a key factor keeping their up tempo drives rolling.
