This offseason, the Eagles' offense went through a significant overhaul when Chip Kelly tried to replace two starting guards on their offensive line, traded for a new quarterback, replaced their running back, and drafted a new starter at wide receiver. Unquestionably, in my opinion, their struggles this season can at least partially be attributed to a lack of continuity.
Conversely, the Eagles' front seven on defense has been playing together for years. Here are the defense's current front seven starters, and how many games they have under their belts in defensive coordinator Billy Davis' system:
| Player | Games played under Bill Davis |
| Fletcher Cox | 39 |
| Bennie Logan | 39 |
| Connor Barwin | 39 |
| Brandon Graham | 39 |
| Cedric Thornton | 37 |
| DeMeco Ryans | 31 |
| Jordan Hicks | 6 |
"It’s improved personnel," Chip Kelly said to reporters Tuesday, "but I also think there’s a comfort level with the players in the system. Brandon’s here for three years, Connor’s here for three years. That front seven, with the exception of Jordan Hicks, has been here for a while. And the fact that you have a player like Malcolm that’s kind of held the back end together, and now Walt, Nolan and Max and Bigs and Chris have all started to form a group back there in the secondary has really helped, but I think that's what's to Billy’s benefit is that continuity that we have up front, because you’ve had the same D line and both of those outside linebackers have played a ton of snaps for us. And really the only addition at inside linebacker is Jordan Hicks, who again, has really exceeded some people’s expectations, not ours, but in terms of what he could handle as a rookie, kinda got thrust into the role because of injuries."
Continuity is one of those things that is difficult to quantify, but its importance is fairly clear, and the results are there. The defense has improved in "per drive" stats every year under Davis (via FootballOutsiders):
| Year | Yards per drive | Rank | Points per drive | Rank |
| 2013 | 32.51 | 25 | 1.79 | 14 |
| 2014 | 29.34 | 7 | 1.85 | 15 |
| 2015 | 29.58 | 9 | 1.55 | 7 |
Those numbers above do not include Monday's win over the Giants when the Eagles allowed just 17.6 yards and 0.5 points per drive. Kelly tried to explain why continuity is an important factor.
"When you have some continuity from that standpoint those guys are going to understand the system to a point where they can make tweaks, they can make adjustments," said Kelly. "The offense presents something to you, and when Billy or (defensive back coach Cory Undlin) or (defensive line coach Jerry Azzinaro) or one of those guys is talking about the adjustment, the guys are finishing their sentences, and not going, ‘Hey they did this. What do we do?’ They already understand what the counter is to it. So I think where Billy’s really benefiting is that whole group has a real good continuity as the back end continues to get better and more experienced."
The offense has almost no continuity, and it isn't playing well. The defense has a lot of continuity and is. Probably not a coincidence.
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