DVOA Week 1: NFC West is Best
The New Orleans Saints lead the Football Outsiders DVOA ratings after Week 1, thanks to their 38-3 dismantling of the Green Bay Packers. But the real headline is the hot start for the NFC West. The four teams from that division all finish in the top six for Week 1, with the Rams at No. 2, the Cardinals at No. 4, the 49ers at No. 5, and the Seahawks at No. 6.
The AFC West also swept its Week 1 games, but those teams are not as high in our ratings after playing closer games. We have Denver at No. 9, the Los Angeles Chargers at No. 15, Las Vegas at No. 15, and Kansas City down at No. 22. The Chiefs are the only team to win in Week 1 despite a lower DVOA rating than their opponent, the Cleveland Browns.
(Of course, though I'm calling our main metric DVOA here, it is actually VOA because there are no opponent adjustments right now. We do not apply opponent adjustments until after Week 4, so in Weeks 1-3 DVOA and VOA are the same thing.)
The close win over Cleveland doesn't hurt the Chiefs very much in our DAVE ratings. Those are the ratings that combine our preseason projection with the results of early games to give us a better prediction of how each team will rank at the end of the year. For those who don't know the story, this metric is called DAVE as a reaction to criticism that our stats are too much alphabet soup. I mean, who can argue with a guy named Dave? (Technically, it stands for "DVOA Adjusted for Variation Early.") In these week's DAVE, the preseason forecast still counts for 93% of the rating. Still, Week 1 did do some shifting to DAVE, with the Saints and Rams in particular moving up while the Packers and Titans fell.
Kansas City beating Cleveland despite the lower DVOA lets me introduce a new toy that I've been playing with over the last few weeks. It's called Post-Game Win Expectancy (PGWE). The idea is this: How often should we expect each team to win an NFL game given how the two teams played overall? We all know there are close games where the "wrong team wins," or at least it seems like the wrong team wins. This is a measurement of that.
This idea comes directly from Bill Connelly, who does something similar for college football. The Football Outsiders NFL PGWE is going to work a bit differently from what Connelly does. His PGWE consists of elements that go into his SP+ formula, such as success rates, marginal explosiveness, turnover chances, and average field position. Our PGWE consists specifically of DVOA splits. Well, technically they are actually VOA splits, because opponent adjustments are not included. (You don't get a bonus for playing Kansas City when it comes to the actual game on the field and turning your play into a win or a loss.) The PGWE formula uses both total VOA and VOA split into passing and rushing, with passing roughly three times as important as rushing in the formula. Yes, as you probably imagine, the team that passes better is more likely to win the game than the team that runs the ball better. Special teams DVOA is also part of the formula.
I tried to include some variables other than VOA splits in my PGWE formula, including penalties or penalty yards, total number of plays, and explosive plays (both plays over 10 yards and plays over 20 yards). None of those ended up improving the correlation with actual wins. One thing I didn't do which is part of Bill Connelly's formula is to account for the idea that interceptions are a somewhat random percentage of passes defensed in the same way that fumble recoveries are a somewhat random percentage of actual fumbles. Instead, DVOA only accounts for the actual interceptions. This is something I want to play around with in the future.
You're probably looking to see the PGWE for Week 1 of the 2021 season, so without further ado:
|Post-Game Win Expectancy, Week 1 2021|
As you can see, not all close games are created equal when it comes to PGWE. The formula believes that the Panthers (34.3% VOA) significantly outplayed the Jets (-40.5%) and the 49ers (39.0% VOA) completely outplayed the Lions (-54.6% VOA). On the other hand, you have three different games where PGWE has an unexpected winner. The specific splits of VOA matter here, because in only one of these games (Chiefs-Browns) did the losing team actually end up with a higher total VOA than the winning team.
The Cincinnati-Minnesota game may be the most interesting one here. Both teams ended up with positive VOA overall, but the PGWE is based on the idea that passing is usually more important than rushing. Therefore, Minnesota ends up with the higher PGWE thanks to an advantage of 51% to 38% in pass offense DVOA, even though Cincinnati had a larger advantage of -9% to -45% in run offense DVOA. Of course, pass/run ratio matters as well, which is why the formula also incoporates total VOA (specifically, total defensive VOA) but even here the Vikings were slightly better, 2.4% to 5.3%. The big difference between PGWE and the result of this game was penalties, where Minnesota had 12 of them for 116 yards while Cincinnati had only three for 15 yards.
The Chargers-Washington game is also about the difference between passing and rushing. This may surprise you given how many accolades Justin Herbert got for some great throws in this game, but it was Washington that finished with the better pass offense VOA, 24% to 4%. The Chargers were the better rushing team, -19% to -37%.The Chargers were the better offense overall because passing is generally more efficient than rushing and was in this game, and the Chargers passed about two-thirds of the time while Washington passed only slightly more than half the time.
The Kansas City-Cleveland result should not surprise you, especially if you know that Cleveland outgained Kansas City on average 8.2 to 6.5 yards per play. As noted above, it wasn't just PGWE, Cleveland also has the higher VOA rating in total for the game.
Last year, there was a .80 correlation between PGWE and actual wins. (This is slightly higher than the correlation that Bill Connelly has for his college version of PGWE, which is .78.) To give an example of the kind of game where the final result is very different from the PGWE, here are the five most "unexpected" wins from the 2020 regular season, the games with the lowest PGWE for the team that took the win:
1) Week 9, New England 30 at New York Jets 27 (6%): This was a Monday night game which the Patriots won with a last-second field goal. Joe Flacco subbed for an injured Sam Darnold and was fantastic, 18-of-25 for 262 yards through the air. So the Jets had 115% pass offense VOA compared to 66% pass offense VOA for the Patriots. Overall, the Jets outgained the Patriots 7.3 to 5.7 yards per play, but the Patriots ran far more plays, 76 to 44. "The winning team ran many more plays despite being less efficient" is a general theme of "unexpected wins." As noted above, I tried to account for this by adding a variable based on the number of plays each team had, but it didn't do anything to improve the formula.
2) Week 12, Arizona 17 at New England 20 (7%): Here we go with the Patriots again. New England won this game despite -144% pass offense VOA. Cam Newton was 9-of-18 for just 84 yards with two interceptions and three sacks. Overall, the Cardinals had more yards per play (4.3 to 3.5) and ran more plays (70 to 51). The Cardinals won the turnover battle (+1) and the two teams had the same number of penalties. In retrospect, a mind-boggling loss for Arizona.
3) Week 2, New Orleans 24 at Las Vegas 34 (12%): You probably remember this game, a Monday night contest where the Saints committed roughly 11 billion penalties. OK, technically it was 10 for 129 yards compared to the Raiders having just three for 13 yards. The Saints outgained the Raiders in this game, 7.4 to just 5.0 yards per play, and the turnover battle was even, and the Saints lost anyway primarily because of all those penalties. Drew Brees looked bad despite gaining all those yards and everybody talked about how his arm as shot. I had to spend a lot of time explaining this one in the DVOA column the next day.
4) Week 5, Indianapolis 23 at Cleveland 32 (16%): This is an interesting one because the two teams were essentially even in offensive and defensive VOA although the Colts did outgain the Browns 5.9 to 5.3 yards per play. The big gap was in special teams, mostly because Isaiah Rodgers had a 101-yard kick return for a touchdown for the Colts. And yet the Colts lost the game anyway.
5) Week 5, Tampa Bay 19 at Chicago 20 (17%): This was a Thursday night game, another one you probably remember. It was brought up for much of the season as evidence that the Buccaneers were struggling even though DVOA had them as one of the top two or three teams in the league. The Bucs outgained the Bears 5.3 to 4.1 yards per play and ran more plays as well, with the turnover battle even at one apiece, but the Bucs had issues finishing drives (four field goals) and then Tom Brady lost track of the downs when the Bucs were trying to come back in the final minute.
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These is the Football Outsiders Top 16 through one week of 2021, 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.) Please note that there are no opponent adjustments in DVOA until after Week 4, which is why it is listed here as VOA.
OFFENSE and DEFENSE VOA are adjusted for 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.
DAVE is a formula which combines our preseason forecast with current DVOA to get a more accurate projection of how a team will play the rest of the season. DAVE is currently 93% preseason forecast and 7% actual performance.
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>
Click here for the full table.