A couple years ago, Pro Football Reference unveiled a feature called "expected points added."
It's helpful because it compares outcomes on each individual play to a historical baseline of how teams have done in similar situations. Therefore, it doesn't penalize an offense or defense based on field position, which gives a more accurate view of how the unit performed.
Here are some observations from the 2017 season:
- The Cardinals' defense was never as bad as the total defense and points allowed metrics showed in the beginning of the year. The unit had a negative-12.83 expected points added total through seven weeks -- negative-1.83 points per game – which was below average but not awful. There's no question, though, that the defense shined after the bye. From weeks 8-17, the group accumulated a plus-80.9 EPA, an average of plus-9.0 points per game. The Cardinals' defense finished with 68.07 expected points added, fifth in the NFL behind the Jaguars (169.54 EPA), the Ravens (94.13), the Vikings (79.44) and the Eagles (71.03).
- The offense, unsurprisingly, struggled throughout the year, especially after the loss of Carson Palmer. The Cardinals had two positive offensive games within their first six – against the Cowboys and Buccaneers -- but failed to break even the rest of the season. The closest they came was in the season finale against the Seahawks, when the offense registered a negative-0.61 figure. The Cardinals ended up 29th in the NFL in offensive EPA, due in large part to the injuries to Palmer, David Johnson, D.J. Humphries, etc.
- The special teams had its issues again early on, but the unit found its way at the end of the season. After only one positive showing in the first 12 games, the group graded out positively in each of the final four games. Punter Andy Lee found a groove, while kicker Phil Dawson went 14-of-15 down the stretch on field goals. That stability played a role in helping the team win three of its final four to finish the season 8-8.