Week 20 DVOA Ratings
As usual after the conference championship games, we're not going to bother with the full 32-team table of weighted DVOA ratings, since there are only two teams left and most teams haven't played for three weeks. We'll just take a quick look at both teams.
Tampa Bay is now No. 1 in both weighted and total DVOA after the Bucs' NFC Championship victory over Green Bay. The Buccaneers have ranked in the top three of DVOA ever since Week 4, including when they were just 7-5 and thought to be struggling. They always were playing better than their win-loss record and our ratings reflected this.
On the other hand, you have the Kansas City Chiefs, the team that conventional wisdom likes more than DVOA. The Chiefs rank only fifth in weighted and total DVOA despite their victory in the AFC Championship, but some of that is due to their Week 17 game where they sat their starters. The Chiefs would rank third if we remove that game.
|KC weighted (No Week 17)||34.1%||3||27.3%||3||-3.3%||15||3.5%||8|
|KC total (No Week 17)||28.4%||3||27.1%||2||-1.0%||13||0.3%||17|
For those who are curious, the team that is second in weighted DVOA between Tampa Bay and Kansas City without Week 17 is Green Bay. The team that is second in total DVOA between Tampa Bay and Kansas City without Week 17 is New Orleans.
Next, here are one-game ratings for the conference championships. As you can see, the Kansas City Chiefs were outstanding, putting up their best single-game DVOA of the year.
We've written numerous times about how DVOA was unimpressed by some of Kansas City's close wins this season. That was not the case in the AFC Championship Game, which was not as close as the final score of 38-24. Buffalo getting that close required a muffed punt recovered by the punt coverage (a rare event) and an onside kick recovery (an even rarer event). Kansas City gained more 1.7 yards per play plus Buffalo had lower third-down efficiency and an interception.
Kansas City's single-game rating of 94.3% was the sixth-highest single game by any team this season. It was by far the highest single game for Kansas City, way past the 54.6% they had for Week 3's win against Baltimore. The Chiefs had their best single game on offense and their second-best game on defense behind that Baltimore win.
This was the latest piece of evidence for the "Kansas City flips the switch" theory. That's the theory that the Chiefs deliberately took it easy with big leads during the regular season, leading to string of wins that ended up a lot closer than they should have been, but were always going to play at a higher level in the postseason when the games really mattered.
The week before, in the divisional round, Kansas City had 71.5% offensive DVOA and -23.2% defensive DVOA in the first half of the game, before Patrick Mahomes went out with an injury. So that's one and a half games in the playoffs where the Chiefs have been absolutely dominant. If they've truly "flipped the switch," they've done it on both offense and defense.
I was not a believer in the "flip the switch" theory because we've never really seen it happen in the NFL. We've had teams go on runs in the postseason, sure, but those were lesser teams in the regular season that got hot, not defending champions with the expectations that the Chiefs had this year. We've seen really good teams with high expectations win a ton of close games and then lose in the playoffs, suggesting that maybe they weren't as good as their win-loss record. There hasn't been a team that underperformed in the regular season and won a bunch of games anyway and then turned it up to a championship level in the playoffs.
Maybe the closest team to this year's Chiefs is the 2009 Indianapolis Colts. That Colts team did far outplay its Pythagorean projection and DVOA, winning a number of close games in the second half of the season before they sat their starters in the final game and a half of the regular season and took two losses. The 2009 Colts won their first two playoff games fairly easily. But in the Super Bowl, the switch flipped back, and they lost to New Orleans despite being 4.5-point favorites.
I went to take a look at the Chiefs compared to a number of other recent outstanding offensive teams, and the way the Chiefs played with a late lead does stand out. In the fourth quarter with a lead of more than eight points, the Chiefs' offensive DVOA dropped to -15.2% while their defensive DVOA ballooned to 23.6%. There's no question, the Chiefs simply let up with a big lead late. Past research suggests that this does give us information about how good the Chiefs will be in the future. But that research is always worth reexploring and questioning. I know there are other metrics that have been improved by lowering the weight of plays when a team has a very high or low win probability.
The Chiefs' decline when defending a big lead late is not unique, but it is distinctive. I went back and looked at ten other top teams from the last few years, from the 2007 Patriots to the 2019 Ravens. The only one of those teams that had a similar trend with a big lead late was the 2011 Green Bay Packers, a team I've already compared the Chiefs to in this space. Like the Chiefs, the 2011 Packers played a number of games that were only close because their opponents scored meaningless points late in the fourth quarter.
The aforementioned 2009 Colts also saw their offense go into a shell with a late lead, but unlike the Chiefs and the 2011 Packers, their defense was just as strong when defending late leads.
I also looked at the Chiefs themselves in 2018 and 2019 and, what do you know, the Chiefs show the same trend in 2018. The decline on offense was even stronger. And like this year's Chiefs, the 2018 Chiefs had some games where opponents scored late to make things closer than they were most of the game. In Week 1, a 31-12 lead against the Chargers ended up 38-28. In Week 8, the Broncos scored twice in the fourth quarter to make the final score 30-23. In Week 13, the Raiders scored 17 points in the fourth quarter to finish the game 40-33. And in Week 15, it actually cost the Chiefs when they allowed the Chargers to score two fourth-quarter touchdowns and a 2-point conversion to win 29-28.
The 2019 Chiefs also showed this trend, although not as strongly as the 2018 and 2020 teams.
Other teams I looked at kept the offense humming even with a late lead. As you probably can guess, the Patriots always kept their offenses going with a late two-score lead. So did the 2013 Broncos and recent Saints teams. Last year's Ravens were not as good on offense with a big fourth-quarter lead but their defense got even better.
Here's a look at these teams. It's by no means a scientific study, but I think it's interesting.
|Top Offensive Teams and Performance Up 9+ Points in Q4, 2007-2020|
Q4 Up 9+
Q4 Up 9+
I have to admit that the Chiefs' performance over the last two weeks has convinced me that the "flip the switch" theory is more accurate than not, and that we need to correct for this tendency in our playoff odds. To try to do that, I created playoff odds based giving Kansas City their final offensive DVOA from 2018. That's the highest of the three seasons for Kansas City's offense, tied for the third-highest offensive DVOA ever, and I think a better proxy for what to expect from the Kansas City offense for the long term. Of course, it's not as good as how the Chiefs have played in the last two games, but we've never done projections based strictly on a two-game sample.
Even with this adjustment, we still only come out with Kansas City winning the Super Bowl 53.2% of the time. That's lower than the odds we had for them in Super Bowl LIV, a year ago at this time. As I said at the start of this article, our numbers really like Tampa Bay this year. That's a very good team that the Chiefs have to beat in two weeks.
I know some of you are wondering, so: If we used the regular weighted DVOA -- adjusted to remove Week 17, like I've been doing the last two weeks -- we would have Tampa Bay as favorites to win the Super Bowl 54.2% of the time. Neither of these projections gives Tampa Bay any home-field advantage.
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