Dallas Tops Final 2021 DVOA Ratings
NFL Week 18 - The Dallas Cowboys finish the 2021 season on top of the Football Outsiders DVOA ratings, with a bit of an extra boost from a bunch of Philadelphia backups. The Cowboys had their best single game of the year on Sunday, putting up 96.0% DVOA with a 51-26 win over the Eagles. This game put the Cowboys over 30% on the year, but it did not put them over the top. Even without Week 18, the Cowboys' DVOA of 28.3% from last week would have narrowly held up as the top rating of the year, keeping the Cowboys ahead of Buffalo and Tampa Bay.
This is the first Cowboys team to finish first in DVOA since the dynasty of the 90s led the league for three straight years from 1992 to 1994. The Cowboys did finish as high as No. 2 since then, with only the New England Patriots beating the Cowboys back in Dak Prescott's rookie year of 2016. The Cowboys were dramatically improved from last year, when they finished 23rd overall, on both offense and defense. We knew that the offense would improve with Prescott once again healthy (improving from 24th to sixth) but we did not have any idea of what the defense could do with the addition of rookie Micah Parsons and coordinator Dan Quinn (improving from 23rd to second).
The Cowboys also finish the regular season as the No. 1 team in weighted DVOA. Their four best games of the year by DVOA all came in the second half of the season, starting with the 43-3 dismantling of the Falcons in Week 10. The Cowboys' only game since then with negative DVOA was their Week 11 loss to Kansas City.
One reason why the Cowboys' rank in DVOA differs from conventional wisdom is penalties. The Cowboys led the NFL with 127 penalties, not counting declined or offsetting flags. Most of these penalties are not included in DVOA because they are not very predictive of future performance.
The Buffalo Bills slipped ahead of the Tampa Bay Buccaneers to finish the year No. 2 in overall DVOA with the Buccaneers third. The Bills are the top defense of the year, while the Buccaneers are the top offense.
The New England Patriots finish the year fourth in total DVOA but second behind only Dallas in weighted DVOA. That's going to take a little bit of explaining. Why does the DVOA system think the Patriots are the best team in the AFC going into the playoffs when they've lost three of their last four games? There are a couple of things going on here.
First, as I've explained in past weeks, the system absolutely loves the Patriots' blowout wins this season. The Patriots have three of the top 10 single games of the year by DVOA, and all three of those games came in the second half of the season. There was also a fourth huge game, their win over Tennessee in Week 11. (Buffalo also had three of the top 10 games of the year, by the way, with the difference that their great games came before or at midseason: Weeks 4, 5, and 10.)
Second, since we're talking weighted DVOA, we're lowering the weights of the early-season games. Games from Weeks 1-3 are now out of the formula entirely. That means two of the Patriots' four games with negative DVOA are gone and a third, the 25-22 narrow win over Houston in Week 5, doesn't matter very much. Of the Patriots' games with bad DVOA this year, only the loss to Indianapolis in Week 15 is recent.
That gets us to the third thing: the DVOA formula does not think that New England's recent losses were particularly bad performances. The Patriots come out slightly above zero, with 2.2% DVOA for their 33-21 loss to Buffalo and 2.3% DVOA for yesterday's 33-24 loss to Miami. Although the Patriots trailed throughout both games, they played better later in each game and got each one within one score. The Bills game is above zero mostly because of opponent adjustments for the Bills defense, but the two teams were closer than you might realize in yards per play, with the Bills at 5.7 and the Patriots at 4.8. The Dolphins game was closer than that. First of all, forget about the final fumble where the Patriots had one desperation play and the Dolphins put an extra six points on the board. The score of the game was really 27-24. The game turned primarily on some strange penalties, fumble recovery luck on an aborted snap, and a big pick-six thrown by Mac Jones. The Patriots actually outgained the Dolphins significantly, 6.4 yards per play to 4.5. That steady yardage gain is more predictive of future performance than the strange penalties, the fumble recovery, or even the pick-six. Miami still ends up with higher DVOA for the game, but the Patriots end up slightly above average.
I'm honest about being a Patriots fan, which is the reason I got into doing football analytics in the first place, so I know there are some people out there who think that we've put the Patriots higher in our ratings because I'm a fan of the team. Nothing could be further from the truth. Having to explain the Patriots' rating over and over again is annoying. The goal of DVOA is to be as accurate as possible to measure how good teams are, not to stoke the hopes of a specific fan base. The lesson of the Patriots is twofold. On one hand, it's another suggestion that we reconsider how we weight plays late in blowouts, because we may be giving too much credit for blowouts compared to "healthy wins," i.e. winning by two or three scores. On the other hand, our stats have been useful in the past for figuring out which teams are overrated or underrated by conventional wisdom, and it's very likely that the Patriots (and, for that matter, the Dallas Cowboys) are better than most fans believe.
Speaking of healthy wins, let's get back to counting down the top teams of 2021. The Los Angeles Rams finished fifth with a good number of those healthy, non-blowout wins. They had 10 games with DVOA that fell between 15% and 60%. Only Tampa Bay had more. The Rams end the season in the top eight for all three phases of the game. Dallas is the only other team to rank in the top 10 for all three phases. The Rams did lose their final game of the season to San Francisco, and the 49ers climb one spot to finish the season sixth. San Francisco ranks fifth on offense and seventh on defense, although they had trouble with special teams (23rd).
Kansas City drops one spot to seventh, and are any Chiefs fans a little worried about not just losing to the Bengals but also letting the Broncos hang around all afternoon? This was supposed to be when the Chiefs were re-establishing themselves as Super Bowl favorites, especially after that blowout win over Pittsburgh in Week 16. I wrote that week about how DVOA for that game came out very differently than expected because the Chiefs folded up shop with a big fourth-quarter lead, and we always argue about whether that's predictive, but the Chiefs haven't exactly been great in the two games since. Well, half of the Chiefs have been great. This is admittedly arbitary endpoint theater, but the Chiefs are back to being the Chiefs over the last four weeks. That's true both on offense, which is back to being stellar, and on defense, which is back to being a problem although not to the same extent as the early part of the season:
|Kansas City DVOA by Week, 2021|
The Chiefs did have a lot of defensive personnel on the COVID list during Weeks 15 and 16, but those are the better games of the last four. Those players have come back and the defense has struggled. Nonetheless, we still have the Chiefs as our AFC favorites, thanks to the No. 2 seed and our ratings putting the 1-seed Titans so low. (We'll come back to that in a little bit.) If the Chiefs can put their usual offense together with that defense from the middle of the season, they're going to win the Super Bowl.
There's a bit of a gap after the Chiefs before you get to our No. 8 team this year, which is also our highest team with a losing record: the Seattle Seahawks. I wrote a few weeks ago about whether the Seahawks were "breaking DVOA" with their weird mixture of super-explosive plays and three-and-outs. Since then, the Seahawks finished up the season by winning four of six games, with positive DVOA for the last five. (They had negative DVOA for their 30-23 Week 13 win over the 49ers, which was the most unlikely win of the year according to our new Post-Game Win Expectancy metric.) At least I can take solace in the fact that DVOA is not the only advanced metric to fall in love with the losing Seahawks this year; ESPN's FPI has them 10th, also the highest team with a losing record.
It's particularly weird to see the Seahawks higher than the 13-4 Green Bay Packers. For that, you can blame the New Orleans Saints as well as Jordan Love. The Packers' total DVOA for the season is still being dragged down by their huge blowout loss to the Saints back in Week 1. The Packers move up to eighth in weighted DVOA, which no longer includes that game. Then the problem is Love's two games subbing in for Aaron Rodgers. In the version of weighted DVOA I use in the playoff odds simulation, I remove the Packers offense from those two games and it moves the Packers up to third behind only the Cowboys and Patriots. That plus the No. 1 seed makes them the clear Super Bowl favorites.
Arizona finishes up the top 10 in total DVOA for the season. They're one of the teams with the biggest gaps between total and weighted DVOA, however. In weighted DVOA, the Cardinals drop to 16th going into this week's playoff game against the Rams. The Cardinals lost four of their last five games and had negative DVOA in all four of those losses.
If you haven't been keeping up with DVOA on a weekly basis this season, you may be wondering where the rest of the playoff teams are. Turns out you have to go down the list some more. The next-highest playoff team after Arizona is Philadelphia at No. 15. Then you have the rest of the AFC playoff teams. Cincinnati is 17th (in part because of a very bad Week 17 with resting starters), Tennessee is 20th, Las Vegas is 21st, and Pittsburgh is 24th. No, Pittsburgh isn't even close to being the worst playoff team we've ever measured, but Tennessee did finish the season as the worst No. 1 seed in DVOA history. In fact, because a narrow win over Houston gave them -4.0% DVOA in Week 18, the Titans finish the season worse than any No. 2 seed in DVOA history as well. Yes, as we've acknowledged, the Titans are healthier now than they've been for most of the season, and the bye week gives them a strong chance to win at least one playoff game. That doesn't change the fact that this was a historically bad regular season for a top seed in the NFL playoffs.
Football Outsiders predicted before the season that the Titans would win the AFC South as the weakest of the division champions, and what happened according to DVOA is that the Titans won the AFC South as the weakest of the division champions. The playoff teams that we did not accurately predict are primarily the teams with lower DVOA ratings: Cincinnati, Las Vegas, and Pittsburgh. We predicted Seattle as a playoff team and instead got them as the non-playoff team with the highest DVOA. All of these facts back up something really remarkable, which is that one thing we did really well in 2021 is predict DVOA. I know, you're saying to yourself, duh, of course you can predict your own metric. But we don't make DVOA up out of whole cloth, it's based on the actual play-by-play performance of each team, so it's not easy to predict. From 2015 to 2020, the correlation of projected DVOA and actual DVOA was .51. For 2021, the correlation of projected DVOA to actual DVOA is .73.
Obviously, I would rather be accurate predicting wins and losses than predicting DVOA, but guess what, that was more accurate than usual too! In fact, it was a little more accurate than DVOA projections. For 2021, the correlation of our preseason mean projected wins to actual wins is .74.
Remarkably, our projections were super accurate this year despite the fact that there was slightly less year-to-year correlation in DVOA compared to usual. Usually, the correlation coefficient for offense is around .50, but for 2020-2021 it was .41. Defense is usually around .38, and this year it was .34. Special teams is usually around .30, and it was about that at .29 this year.
In past years, we've tracked how teams have done compared to history. Other than the Titans as the worst no. 1 seed, there weren't a lot of teams this year that had DVOA that ranked among the best or worst of the last 38 years. The other exception is the Houston Texans running game. At one point, the Texans were on pace to have the worst run offense DVOA in history. Things improved a bit after that, with Houston putting up -14.8% run offense DVOA in the final five weeks. As a result, the Texans only end up as the fifth-worst running game in DVOA history.
|Worst Run Offense DVOA, 1983-2021|
The Atlanta Falcons were also on pace to make this list, but they also improved running the ball at the end of the season and don't make the historical worst running games list despite ranking 31st in run offense this year.
Houston had the worst overall offense for most of the year but didn't end up in last place thanks to Davis Mills improving at the end of the season. Jacksonville takes up the last place spot in overall DVOA even after beating Indianapolis in Week 18. The New York Giants are the worst offense and the New York Jets are the worst defense. Green Bay finishes with the worst special teams.
A few more notes on 2021 before we get to the big table:
- One of the most remarkable streaks in Football Outsiders' advanced metrics is (probably) over. The New England Patriots had finished with above-average special teams every year since 1995. That goes all the way back before Bill Belichick and even before Pete Carroll to the Parcells era. This year, the Patriots end the season just ever so slightly below average at -0.046%. That's an incredible run, especially since special teams are so much less consistent than offense or defense. Now, you may notice I say that this streak is "probably" over. The Patriots finished so close to zero that it's easy to imagine something putting them back over average: postseason stat corrections, or changes in the league average baseline caused by postseason stat corrections, or future changes to the special teams formula. But for now, the Patriots' special teams streak has ended.
- The Arizona Cardinals ended the season with absurd fumble recovery luck on the offensive side of the ball. Part of this is that they had what looks like a modern NFL record with 16 aborted snaps. I combed through our play-by-play data back to 2010 and couldn't find another team with more than 11 of them in a season. Aborted snaps are usually recovered by the offense, but not always. So it's still remarkable that Arizona fumbled 25 times on offense and recovered 23 of them!
- Other teams with strong fumble recovery luck, particularly on offense, included Dallas and Minnesota.
- Teams with poor fumble recovery luck overall included Cleveland, Jacksonville, the New York Jets, and the Tennessee Titans (13 fumbles on defense, only three recovered).
- Washington, the New York Giants, and Arizona end the season with the toughest schedules by average DVOA of opponent. Pittsburgh had the hardest schedule in the AFC, although Kansas City's schedule was also notably difficult (sixth).
- Buffalo had the easiest schedule in the league this year but it ended up nowhere near as easy as it looked earlier in the season. At one point it looked like the Bills might challenge the 1999 Rams and 1991 Bills for the easiest schedule in DVOA history. Instead, they don't even finish with one of the 100 easiest schedules we've ever measured. Tampa Bay, Cincinnati, Denver, and Philadelphia also had particularly easy schedules. Denver and Cincinnati's schedules were particularly easy on offense, while Buffalo and Tampa Bay's schedules were particularly easy on defense.
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We'll review the best and worst player stats of the year in a special Quick Reads tomorrow.
Please note that while this article is called "Final 2021 DVOA Ratings," we will continue with postseason weighted DVOA ratings each Monday through the playoffs. There also may be small changes in the final 2021 DVOA ratings based on postseason changes to the play-by-play.
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Here is the Football Outsiders team efficiency ratings through the entire 2021 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 for opponent and performance indoors and 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 gives recent games more strength than older games to get a better idea of how well teams are playing now.
LAST YEAR represents rank in 2020.
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>
For the full table, including variance, schedule strength, and non-adjusted VOA, visit the Football Outsiders DVOA database.