Week 15 DVOA Ratings
by Aaron Schatz
The Los Angeles Chargers may have won DVOA Bowl XIX last Thursday night, but it was surprisingly the Kansas City Chiefs who ended up with a higher rating from the game, so the No. 1 Chiefs open up a slightly wider margin over the No. 2 Chargers this week. After those two AFC West squads come the New Orleans Saints at No. 3, passing the Los Angeles Rams at No. 4, and then the Chicago Bears at No. 5.
The Saints moved up nearly two percentage points in total DVOA this week even though their offense struggled once again on Monday night. The Saints and Rams have both been going through some problems on the offensive side of the ball in the month of December. The Rams are averaging 19.9 points in their last three games, the Saints just 16.7 points. Check out this table of the top offenses in the league through Week 12 and what's happened to them in the three weeks since:
Both the Saints and Rams have somewhat made this up on the defensive side of the ball, but the Saints have done so much more than the Rams have. The Rams' defensive DVOA has improved to -11.5% over these three games, but the Saints' defensive DVOA is -23.4% over the last three games. Over the last six games, the Saints have defensive DVOA of -26.9%, second only behind Chicago.
The Rams and Saints have been just the two most obvious examples of a strong trend that started at the beginning of the month, back in Week 13. Remember that historic level of offense we were seeing for the first three months of the season? It's gone away in the month of December. This has affected most of the offenses in the league, even the teams that have continued to have top offenses in December. From the table above, you can see that the Chiefs and Chargers remained No. 1 and No. 3 in offense. But notice that their offensive DVOA still dropped, even if their ranks stayed the same. (If you're curious which team has been second in offensive DVOA since Week 13, it's the New England Patriots, despite going 1-2 in those games.)
|December's Offensive Decline, 2018|
So you're probably asking, what's the reason why defenses have been playing better in December? Does this have anything to do with the weather? Could it be because players are dealing with more injuries and fatigue by this point in the season?
Going back over past years, the answer appears to be yes. I looked at the past eight years and in six of them, the league as a whole had a lower DVOA in Weeks 13-17 compared to Weeks 1-12. So far this year's difference is a lot larger than it usually is. I'm guessing that's just random variation, and offense will improve in the next two weeks so that the gap between Weeks 1-12 and Weeks 13-17 is closer to what we usually see.
|December's Offensive Decline, 2011-2018|
|League DVOA Wk 1-12||1.7%||0.4%||1.1%||0.1%||1.6%||0.0%||0.3%||-0.7%|
|League DVOA Wk 13-17||-6.1%||-0.8%||-2.5%||-0.3%||-3.7%||0.0%||-0.8%||1.6%|
|Yd/Play Wk 1-12||5.82||5.40||5.61||5.60||5.57||5.47||5.55||5.55|
|Yd/Play Wk 13-17||5.34||5.30||5.48||5.53||5.47||5.44||5.42||5.60|
Back to the topic of the New Orleans Saints: Week 15 is the first week of the season where one of this year's games falls completely out of the weighted DVOA formula. Weighted DVOA no longer counts Week 1, and the Saints' 48-40 loss to Tampa Bay was their second-worst game of the year by DVOA. (The worst was the loss to Dallas in Week 13.) The Saints also had a nice 40.9% DVOA for their win over Carolina. Add that in, take out Week 1 entirely, and the Saints have passed the Los Angeles Chargers for No. 2 in weighted DVOA.
Combine New Orleans' rise in weighted DVOA with the recent fall of the Rams -- along with the small chance that the Chargers will knock the Chiefs out of a division title -- and the Saints have now taken over from Kansas City as our Super Bowl favorites. They win the Lombardi Trophy in 28.1 percent of our simulations.
The Saints are one of three teams that now have weighted DVOA that is 7.0% higher than their total DVOA. The others are Buffalo and Detroit; both teams have been generally better in recent weeks but they also now have their horrific Week 1 offensive performances wiped out of the weighted ratings. Cleveland, Tennessee, and Indianapolis are also significantly better by weighted DVOA (6.0% difference, or close to it).
On the other side, the team that stands out for decline in the second half of the season is the Miami Dolphins. Miami is at -10.5% in total DVOA (24th) but -19.4% in weighted DVOA (28th). Other teams that have faded in the second half include the Jets, Bengals, and Redskins. No surprise that all four teams have dealt with starting quarterback injuries, and yes, that includes the Jets. Josh McCown has lower passing DVOA than Sam Darnold this season.
One other team that deserves mention for improvement, even though it's only been on one side of the ball: Cleveland. The Browns are 25th in offensive DVOA at -7.0% but they move up to 14th in weighted offensive DVOA at 1.8%. Since they fired head coach Hue Jackson and offensive coordinator Todd Haley before Week 9, the Browns rank fourth in the league with 18.2% offensive DVOA, behind the Chiefs, Chargers, and Steelers. Over that same period, only Patrick Mahomes (38.9%) has a higher passing DVOA than Baker Mayfield (36.0%).
The second biggest offensive improvement since the early part of the season belongs to the Buffalo Bills. Remember when we were tracking whether the Bills would end up with the worst offensive DVOA of all-time? Since their bye week in Week 10, the Bills rank 19th in the league with -3.6% offensive DVOA. And they're now off the "12 worst offensive DVOA through X games" list.
The same can't be said for the Arizona Cardinals. The Cardinals were so bad against Atlanta that they actually benched Josh Rosen and brought in Mike Glennon. Arizona's -103.0% offensive DVOA against Atlanta was its worst single game of the year, and the worst offensive game any team has had since Buffalo and Detroit got smacked down back in Week 1. Arizona's offensive rating falls from -38.8% to -42.5% this week, but that's still not enough to drop them to the bottom of the list of worst offenses in DVOA history:
|BEST OFFENSIVE DVOA
THROUGH 14 GAMES, 1986-2018
|WORST OFFENSIVE DVOA
THROUGH 14 GAMES, 1986-2018
Finally, I have to give an important caveat that always comes up when I talk about weighted DVOA late in the year. Weighted DVOA helps us tell the story of how a team's season has gone, and helps us as a guide to how well teams have played in recent weeks. However, except when it's clearly related to major injuries, weighted DVOA doesn't actually predict playoff results any better than full-season DVOA. Trying to create a weighted DVOA that does a better job of predicting the postseason is one of those things we're always working on (or trying to find time to work on) but it's still best to take the long view of how a team has played. Even weighted DVOA takes a long view, including 14 weeks of data with the last eight weeks at nearly full strength.
* * * * *
* * * * *
These are the Football Outsiders team efficiency ratings through 15 weeks of 2018, measured by our proprietary Defense-adjusted Value Over Average (DVOA) system that breaks down every single play and compares a team's performance to the league average based on situation in order to determine value over average. (Explained further here.)
OFFENSE and DEFENSE DVOA are adjusted to consider all fumbles, kept or lost, as equal value. SPECIAL TEAMS DVOA is adjusted for type of stadium (warm, cold, dome, Denver) and week of season. As always, positive numbers represent more points so DEFENSE is better when it is NEGATIVE.
WEIGHTED DVOA represents an attempt to figure out how a team is playing right now, as opposed to over the season as a whole, by making recent games more important than earlier games.
To save people some time, please use the following format for all complaints:
<team> is clearly ranked <too high/too low> because <reason unrelated to DVOA>. <subjective ranking system> is way better than this. <unrelated team-supporting or -denigrating comment, preferably with poor spelling and/or chat-acceptable spelling>
- NON-ADJUSTED TOTAL DVOA does not include the adjustments for opponent strength or the adjustments for weather and altitude in special teams, and only penalizes offenses for lost fumbles rather than all fumbles.
- ESTIMATED WINS uses a statistic known as "Forest Index" that emphasizes consistency as well as DVOA in the most important specific situations: red zone defense, first quarter offense, and performance in the second half when the score is close. It then projects a number of wins adjusted to a league-average schedule and a league-average rate of recovering fumbles. Teams that have had their bye week are projected as if they had played one game per week.
- PAST SCHEDULE lists average DVOA of opponents played this season, ranked from hardest schedule (#1, most positive) to easiest schedule (#32, most negative). It is not adjusted for which games are home or road.
- FUTURE SCHEDULE lists average DVOA of opponents still left to play this season, ranked from hardest schedule (#1, most positive) to easiest schedule (#32, most negative). It is not adjusted for which games are home or road.
- VARIANCE measures the statistical variance of the team's weekly DVOA performance. Teams are ranked from most consistent (#1, lowest variance) to least consistent (#32, highest variance).