by Aaron Schatz
A week with some big blowouts leads to some big moves up and down in the Football Outsiders DVOA ratings. But since two of those blowout winners were already on top of our ratings, we have the same top two as we did a week ago: Kansas City at No. 1 and the Los Angeles Rams right behind them at No. 2. And with Chicago losing to New England and dropping to No. 6, we're back to having a huge gap at the top of the DVOA ratings, this time between the top two teams and everyone else. Right now, the gap between the Rams and the No. 3 Los Angeles Chargers is roughly equal to the gap between the Chargers and the No. 13 Houston Texans.
The biggest riser in this week's ratings is the Denver Broncos, who move all the way up from No. 13 last week to No. 5 this week after their Thursday night 45-10 dismantling of the Arizona Cardinals. I'm going to guess that this rank seems a bit too high to all of our readers. You probably won't find the Broncos anywhere No. 5 in any power rankings anywhere else on the Internet. You probably won't even find the Broncos in the top ten. It certainly seems like the DVOA system is substantially overreacting to one huge win over a very bad team. But a closer look at Denver's schedule does a lot to explain why DVOA likes them so much. The Broncos' past schedule currently ranks sixth in the NFL. They lost to the Chiefs and the Rams, the two best teams in the NFL, by a combined seven points.
Let's go through the schedule and see if we can figure out how Denver ended up so high. The opponents here are listed with their current DVOA rank.
Week 1: 27-24 win over Seattle (10) with 49.4% DVOA. The DVOA rating seems a bit high for the final score, even considering that Seattle is an above-average opponent, but the Broncos outgained the Seahawks 470 yards to 306 yards (6.5 yards per play vs. 5.6 yards per play).
Week 2: 20-19 win over Oakland (29) with -31.0% DVOA. When you have a very close win over a very bad team, you should have a bad DVOA rating, and the Broncos do here.
Week 3: 27-14 loss to Baltimore (4) with -4.2% DVOA. DVOA is a little closer than expected, but that's not a strange rating for a loss to a top opponent. The Broncos had a couple of significant drives that didn't result in points. One had 63 yards of offensive gains but lost 30 yards to penalties; the other came in the final quarter and stalled out on fourth-and-6 from the Baltimore 11.
Week 4: 27-23 loss to Kansas City (1) with 24.3% DVOA. Denver had a larger average gain than the best offense in football, 6.5 yards per play vs. 6.2 yards per play, but also had the game's only turnover. It's a blown 23-13 lead, but DVOA doesn't penalize Denver for poor clutch play.
Week 5: 34-16 loss to New York Jets (20) with -12.3% DVOA. This is probably Denver's most surprising single-game rating, especially since they recovered all three of the fumbles in this game and were outgained, 8.4 yards per play to 6.1 yards per play. I think in part what we're seeing here is DVOA's preference for steady mid-length gains over big plays, because big plays that go the length of the field are less predictive than constant gains. The Jets got two touchdowns off a 77-yard Isaiah Crowell run and a 76-yard Robby Anderson catch.
Week 6: 23-20 loss to Los Angeles Rams (2) with 26.3% DVOA. Here's another close game against one of the two top teams in the league, so the Broncos get a good rating for it.
Week 7: 45-10 win over Arizona (31) with 87.1% DVOA. The biggest blowout of the week by DVOA.
There is one other variable involved here, and that is that four of these seven games were at home. I've never been able to get a home/away adjustment into DVOA in a way that worked and increased correlation with future performance, but of course it matters. So if we had an adjustment, Denver's rating would be a little bit lower. The Broncos would probably be sixth instead of fifth. Still higher than conventional wisdom. I'll say the same thing about Denver's rating that I usually say when we have a team that's unexpectedly high: this rating may be a bit too high, but it's probably a good sign that this team is being underrated by conventional statistics.
Denver is one of six teams this week that move up or down at least five spots in the DVOA rankings. The others?
Moving up: Houston (from 18 to 13), Indianapolis (from 19 to 14), and Minnesota (from 21 to 16).
Moving down: Cincinnati (from 12 to 22) and Miami (from 6 to 11).
Of course, just like the Chiefs and Rams can move up in DVOA but can't move up in rank from No. 1 and No. 2, so too the Cardinals and Bills can move down in DVOA but can't move down in rank from No. 31 and No. 32. And boy oh boy, did the Cardinals and Bills move down this week. Buffalo's total DVOA dropped from -36.5% to -43.5%. Arizona's dropped even more, from -26.2% to -36.6%.
In particular, Arizona plummeted on offense, from -31.3% to -39.9%. That puts the Cardinals into rare territory as one of the ten worst offenses we've ever tracked through seven games. But the Cardinals still can't even come close to the impotence of the Buffalo Bills. Buffalo's offensive DVOA stayed relatively constant after the Indianapolis blowout, going from -53.4% to -53.2%. But most of the worst offenses we've ever tracked weren't staying constant around Week 7 -- they were starting to come back from their horrendous starts, slowly improving their ratings.
Which means that the 2018 Buffalo Bills are now the worst offense in DVOA history, at least through seven games.
|BEST OFFENSIVE DVOA
THROUGH 7 GAMES, 1986-2018
|WORST OFFENSIVE DVOA
THROUGH 7 GAMES, 1986-2018
This is the lowest that any offense has ever been this late in the season. There's only one other time that any offense has been below -50% after Week 6: in 2005, the San Francisco 49ers fell to -53.0% for one week after they gained only 299 total yards in their Week 9 and Week 10 losses. They bounced back up above the -50% line the following week.
On the positive side, you'll notice that Kansas City's big win over Cincinnati bumped the Chiefs back into the all-time offensive top ten. However, the Chiefs had their worst special teams of the year (-7.9% DVOA) in this game so their special teams narrowly dropped out of the all-time top ten.
One other interesting trend to note: With last week's top defenses all giving up at least 24 points this weekend, the defensive DVOA ratings have become extremely tight. Chicago is still the No. 1 defense, but they climbed from -21.2% to -15.8%. Cleveland is now No. 2 at -14.5% with Baltimore dropping to third at -14.0%. This is the worst the top defenses have ever been in DVOA history. Previously, the year with the least impressive No. 1 defense after Week 7 was 2003, when the Dallas Cowboys were No. 1 at -17.0%. This is only the third time in DVOA history that the No. 1 defense after Week 7 isn't better than -20%.
On the other side, Tampa Bay is about average historically for the worst defense in the league at this point. The Bucs are no longer among the worst defenses we've ever tracked.
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These are the Football Outsiders team efficiency ratings through seven 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.
Because it is early in the season, opponent adjustments are only at 70 percent strength; they will increase 10 percent every week through Week 10. As always, positive numbers represent more points so DEFENSE is better when it is NEGATIVE.
DAVE is a formula which combines our preseason projection with current DVOA to get a more accurate forecast of how a team will play the rest of the season. Right now, the preseason projection makes up 20 percent of DAVE for most teams (30 percent for teams with just six games played).
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).