Final 2018 DVOA Ratings
by Aaron Schatz
For regular readers of Football Outsiders, the 2018 DVOA champion is no surprise. The Kansas City Chiefs moved into our No. 1 spot after Week 6 -- oddly, they weren't number one until after their first loss of the season -- and they've been on top ever since. At midseason, the Chiefs ranked among the best overall teams we had ever tracked, and although they've faded from that high, they easily take the crown as this year's No. 1 team in DVOA.
The Chiefs also finish the season No. 1 in weighted DVOA, followed by the Saints and Chargers. The Indianapolis Colts look like the hot team going into the playoffs, ranking eighth in total-season DVOA but fourth in weighted DVOA. The opposite, a team that's slowed down in the second half of the year, is the Los Angeles Rams. The Rams move up this week to finish the season No. 2 in overall DVOA, but they are only sixth in weighted DVOA.
2018 was a year of parity. Thanks to reader nat and our own Vincent Verhei for figuring this out last week, but you'll notice that there's only one team this year above 25% DVOA and only one team below -25% DVOA. There's only one other season where that happened, which was 2003. Ironically, the one team above 25% in 2003 was Kansas City, and the one team below -25% was Arizona, the same teams as this year.
This was also a year of consistency, at least consistency from season to season. If you've been reading Football Outsiders for a long time, you know one of our main axioms is that offense is more consistent than defense, while both are more consistent than special teams. You may remember that this was completely switched around in 2017; the correlation from 2016 to 2017 was better for special teams than for defense, and better for defense than for offense.
However, comparing this year to last year in DVOA, you can see that teams stayed surprisingly consistent from 2017 to 2018, except in special teams. That's a bit of a surprise when you consider that only five of 12 playoff teams repeated. But there were a number of teams that missed the playoffs but still had high DVOA ratings more similar to last year. Seven of the top ten teams in DVOA from 2017 repeated in 2018, but that includes non-playoff teams Pittsburgh (dropped from third to ninth) and Minnesota (dropped from fourth to tenth). None of the teams from last year's top ten dropped into this year's bottom ten, although two teams went in the other direction: Chicago from 25th to fifth and Indianapolis from 31st to eighth. Looking at each unit:
- The top six offenses of 2018 all ranked among the top seven offenses of 2017. The year-to-year correlation of offensive DVOA is usually around .50 and was only .33 from 2016-2017. This year it was .58.
- The correlation wasn't quite as high on defense, but last year's top three defenses were all in this year's top six, and every one of the defenses in the bottom ten for 2018 was below average in 2017. The year-to-year correlation of defensive DVOA is usually around .38 but this year it was .49.
- Special teams had almost no similarity from year to year. Four of the top five special teams units of 2018 were among the bottom ten special teams units of 2017. The year-to-year correlation of special teams DVOA is normally around .30 but was a negligible .04 from 2017 to 2018.
All year long, we've been tracking how well the Kansas City Chiefs were doing compared to the best offenses in DVOA history. They finish with the No. 5 offense in DVOA history, which is still pretty remarkable considering how much their numbers are adjusted downward for the overall high offensive level around the league this year.
|BEST OFFENSIVE DVOA,
The Chiefs stand out among the best offenses of all-time for their balance, first in passing and fourth in rushing. Note also that the Chiefs put up those incredible offensive numbers against a harder-than-average schedule of opposing defenses, including two top-ten defenses in their division. Kansas City's offensive rating is raised significantly by an absurdly strong 119.2% offensive DVOA against Cleveland in Week 9. However, even if we remove that offensive performance, Kansas City would still finish the year No. 1 in offensive DVOA (29.8%) and total DVOA (28.6%).
We've also spent the year tracking Arizona and Buffalo as they competed for the title of worst offense in DVOA history. Buffalo looked like they were going to win this dubious honor through the first half of the season, but the Bills' offense improved dramatially after midseason. From Week 10 to Week 17, Buffalo had an offensive DVOA of -1.2%, almost average! The same can't be said for Arizona, which actually got worse on offense in the second half of the year. As a result, after adjusting for era, the Cardinals end up with the third-worst offense in DVOA history.
|WORST OFFENSIVE DVOA,
With average defense and close-to-average special teams combined with this hideous offense, the Cardinals ended up way, way, way behind every other team in the league in DVOA this year. Arizona was at -40.4%, and the next worst team was Oakland all the way up at -21.0%. The difference between Arizona and Oakland was almost equal to the difference between Oakland and a league-average team such as Philadelphia or the New York Giants (both of whom, rounded to a single decimal, finished at 0.0%).
The only season with a bigger difference between the worst team and the next-worst team was 2005, when the 49ers had the worst total DVOA in history.
On defense, our clear leaders this season were the Chicago Bears. Their big win over Minnesota moves them down to -25.6%, which is close to the best defenses in DVOA history. (The Bears end up 12th.) There's a hefty gap between the Bears and the No. 2 defense, which surprisingly belongs to the Buffalo Bills. The gap between the Bears and the Bills is roughly equal to the defensive gap between the Bills and No. 10 Indianapolis.
The Bears stand out because they excelled against both the pass and the run. However, they were not the most historically great run defense this season. That title belongs to the Houston Texans. The Texans were only 18th against the pass but finished first against the run with one of the top ten run defenses in DVOA history. We'll extend this table a couple more teams so we can get the Bears on here too:
|BEST RUN DEFENSE DVOA,
The worst defenses of the year were in the NFC South, Tampa Bay and Atlanta, but once again this year, no team particularly stood out as horrible on defense. Last year, Tampa Bay had the best defensive DVOA ever for a team that finished in last place on defense. This year, Tampa Bay has the seventh-best defensive DVOA ever for a team that finished in last place on defense.
At one point it looked like the Kansas City Chiefs were going to end up with the worst run defense in at least a decade, but they improved at the end of the season, so while they end up dead last in run defense, they aren't historically bad. The Chiefs were one of several teams with a really strong dichotomy between run defense and pass defense:
- Kansas City was No. 32 vs. the run but No. 12 vs. the pass
- Arizona was No. 29 vs. the run but No. 8 vs. the pass
- Los Angeles Rams were No. 28 vs. the run but No. 9 vs. the pass
- Cleveland was No. 25 vs. the run but No. 7 vs. the pass
On the other hand...
- Houston was No. 1 vs. the run, No. 18 vs. the pass
- New Orleans was No. 3 vs. the run, No. 22 vs. the pass
- Indianapolis was No. 4 vs. the run, No. 24 vs. the pass
The New York Jets are the top special teams unit of 2018 with 8.1% DVOA. They led the league in punt return value and were second in kick return value, both thanks to Andre Roberts, and they finished fourth in both field goal value and kickoff value thanks to Jason Myers. The Chiefs had the best special teams early in the season, then faded at midseason, but rebounded with strong games in both Week 15 and Week 16. They finish second. The Buffalo Bills end up with the worst special teams unit in the league, 21st or lower in all five phases.
But perhaps the most interesting special teams finish is right in the middle. The New England Patriots somehow ended up dead last in the net kickoff value despite having Stephen Gostkowski, historically one of the top kickoff men in the league. But the Patriots got enough value out of kick returns and punts to finish just barely over average, 16th at 0.1%. And that finish makes this the mind-boggling 23rd straight season where the New England Patriots had above-average special teams, a streak that goes back before Bill Belichick to the end of the Bill Parcells era and the 1996 Super Bowl team.
Almost as impressive: Baltimore finished sixth in special teams, making this the seventh straight year for the Ravens in the special teams top six. The Ravens have finished eighth or higher in special teams DVOA in nine of the last ten seasons.
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All player/team DVOA stats pages are now updated through the end of the regular season, as are our playoff odds. Snap counts and the premium DVOA database should be updated by the end of tonight. Drive stats and pace stats are updated with final numbers. Matchup View in FO Standard Premium will be added for the four wild-card games sometime on Tuesday.
With New Year's Day stuck on Tuesday, a lot of our usual Tuesday material will be moved to Wednesday this week. Vincent Verhei will discuss which players had the best and worst seasons by FO stats in Quick Reads Year in Review on Wednesday. Loser League results will be announced in Scramble for the Ball on either Wednesday or Thursday, depending on when we finish the annual Staff Playoff Fantasy Draft. The Playoff Challenge game will also go up on Wednesday. Our December players for Madden 19 will be announced Wednesday in a special Extra Points post and from our Twitter account, @fboutsiders.
Please note that while this article is called "Final 2018 DVOA Ratings," we will continue with our unofficial postseason weighted DVOA ratings each Monday through the playoffs.
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These are the Football Outsiders team efficiency ratings through the entire 2018 regular season, 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. 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. As always, positive numbers represent more points so DEFENSE is better when it is NEGATIVE.
LAST WEEK represents rank after Week 17, while LAST YEAR represents rank in 2017.
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 VOA does not include adjustments for opponents and for measuring all fumbles equally no matter who recovers.
- 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.
- 2018 SCHEDULE lists average DVOA of opponents played this season, ranked from hardest schedule (#1, most positive) to easiest schedule (#32, most negative).
- PYTHAGOREAN WINS represent a projection of the team's expected wins based solely on points scored and allowed.
- 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).