The Philadelphia Eagles are one of the more confusing teams in the NFL. At 4-4, it’s easy to assume that the Eagles are an average team, yet Philly has outscored opponents by 57 points this season, the third-best differential behind the 7-1 Cowboys and 7-1 Patriots. Furthermore, Football Outsiders has the Eagles first in the NFL in defense-adjusted value over average, a metric that measures team performance on a play-by-play basis. So what’s the deal — are the Eagles secretly one of the best teams in the league, or have they somehow gamed the system?

The obvious reason the Eagles are 4-4 despite putting up impressive numbers in the two stats mentioned above is that they clustered a lot of very strong play into just four games. In the team’s four wins, the Eagles have outscored opponents by a total of 76 points, an average of 19 points per victory. That makes Philadelphia one of four teams with an average margin of victory of at least 19 points in wins, joined by the Steelers (19.3 in four wins), Cardinals (23.3 in three wins) and 49ers (28.0 in one win).

Meanwhile, the Eagles’ average margin of defeat in four losses is just 4.75 points, tied for the fifth-smallest margin. To put it another way, the point spread between the Eagles and their opponents is 14.25 points higher when Philadelphia wins than when it loses. That’s an inefficient way to rack up wins, of course. In fact, only the Cardinals have a larger disparity in their results in wins versus losses.

AVERAGE POINT DIFFERENTIAL IN … TEAM RECORD WINS LOSSES DIFF 1 Arizona 3-4-1 +23.3 -7.8 +15.6 2 Philadelphia 4-4 +19.0 -4.8 +14.3 3 Dallas 7-1 +12.0 -1.0 +11.0 4 San Francisco 1-7 +28.0 -17.3 +10.7 5 Buffalo 4-5 +17.8 -7.4 +10.4 6 San Diego 4-5 +10.8 -4.4 +6.4 7 Atlanta 6-3 +9.7 -4.0 +5.7 8 Carolina 3-5 +10.7 -6.8 +3.9 9 Denver 6-3 +12.2 -8.3 +3.8 10 Pittsburgh 4-4 +19.3 -16.0 +3.3 11 Green Bay 4-4 +8.5 -5.8 +2.8 12 Seattle 5-2-1 +7.8 -5.5 +2.3 13 Minnesota 5-3 +11.2 -9.0 +2.2 14 New Orleans 4-4 +6.8 -5.8 +1.0 15 Baltimore 4-4 +5.0 -4.8 +0.3 16 Tennessee 4-5 +7.5 -7.8 -0.3 17 Detroit 5-4 +3.4 -4.5 -1.1 18 New England 7-1 +14.4 -16.0 -1.6 T19 Miami 4-4 +7.0 -9.3 -2.3 T19 Indianapolis 4-5 +5.8 -8.0 -2.3 21 Cincinnati 3-4-1 +10.0 -13.0 -3.0 22 Washington 4-3-1 +6.5 -9.7 -3.2 T23 Chicago 2-6 +6.5 -10.2 -3.7 T23 N.Y. Giants 5-3 +4.0 -7.7 -3.7 25 Oakland 7-2 +6.4 -11.5 -5.1 26 Los Angeles 3-5 +5.0 -10.4 -5.4 27 Kansas City 6-2 +11.7 -18.0 -6.3 28 Tampa Bay 3-5 +9.0 -15.8 -6.8 29 N.Y. Jets 3-6 +5.7 -13.2 -7.5 30 Jacksonville 2-6 +2.0 -11.0 -9.0 31 Houston 5-3 +6.6 -21.0 -14.4 2016′s most unbalanced point differentials Numbers may not add up due to rounding. All information is through Week 9. Source: pro-football-reference.com

So Philadelphia is inadvertently testing the limits of two football analytics maxims: Good teams win in blowouts, and winning close games isn’t a skill. The Eagles are 0-4 in close games — that is, games decided by 7 or fewer points — which makes them tied with the Brown and Bills for the worst rate in the league. But unlike Cleveland and Buffalo, Philadelphia is 4-0 in games decided by 8 or more points. In fact, since 1970, Philadelphia is just the 4th team to start 4-0 in close games and 0-4 in other games, joining the 2006 Eagles, the 2005 Chargers and the 1991 49ers. Those three teams went 6-2, 5-3 and 6-2, respectively, in the second half of the season.

Taking a broader look, winning big holds more predictive power than a team’s struggles in close games. I analyzed all 16-game seasons in NFL history and broke each team’s season into two halves: the first eight games and last eight games. I figured out how many games above or below .500 each team was in close games and how many games above or below .500 each team was in games that weren’t close, and then I calculated how those two variables affected the team’s record in the second half. In short, things look good for the Eagles.

Given their current record in close games and games that aren’t close, the Eagles would be expected to win 4.8 games the rest of the season. Had those numbers been flipped — i.e., 0-4 in games that aren’t close but 4-0 in close games — Philadelphia would be expected to win just 3.2 games the rest of the year. And, of course, had the Eagles been 2-2 in both sets of games, they would be expected to win 4.0 games over the rest of the year. So the way in which the Eagles have arrived at 4-4 does hold some predictive power.

But it’s not all good news for the Eagles’ prospects. While the team may have outplayed its record, that’s partly because the Eagles have been great on special teams but below average on offense. According to Football Outsiders, the Eagles rank 23rd on offense, first on defense, and first in special teams. And according to ESPN’s expected points added rankings, Philadelphia’s offense ranks 23rd, its defense ranks fourth, and its special teams rank third. Research shows that offensive success is more sustainable than success on defense or special teams, in part because a team’s offense matters more than its defense in determining the final score of a given game. And the offense may not be in a position to turn things around, as rookie QB Carson Wentz has not looked as sharp lately after beginning the year on fire — possibly because teams have had more time to scout him.

So while the Eagles may be playing better than their record, the way they’re doing it may be unsustainable. (In addition to being better on defense than offense, Philadelphia has also had outstanding fumble recovery luck this year, which is another type of performance that cannot be sustained.) And since Week 5, Carson Wentz ranks 31st out of 33 quarterbacks in adjusted yards per attempt. Philadelphia is just 1-4 since a surprising 3-0 start, and the team faces the second-hardest schedule in the league in its remaining games. Currently, ESPN projects the team with just a 51.9 percent chance of making the playoffs, down from 70.2 percent five weeks ago.