Packers vs. Pythagoras (and DVOA)

NFL Week 15 – The Tampa Bay Buccaneers hold on to the top spot in our DVOA ratings this week despite their 9-0 loss to New Orleans on Sunday night. Tampa Bay’s rating dropped from 30.8% to 28.0% but that’s enough to keep the Buccaneers ahead of the rising Dallas Cowboys and Buffalo Bills, who rank second and third after convincing victories over lesser opponents. The Los Angeles Rams rank fourth going into tonight’s game with Seattle.

The New England Patriots drop from second to fifth in overall DVOA but they are still No. 1 in Weighted DVOA even after Saturday night’s loss to Indianapolis. The Patriots had enough of a huge lead on the rest of the league from playing so well over the past two months that they keep the top spot even with Weighted DVOA dropping from 37.9% to 29.0%. The Patriots are followed by Kansas City, San Francisco, and Indianapolis, who each move up one spot with the Arizona Cardinals dropping from sixth to ninth after losing to Detroit. Then the Green Bay Packers finish up the top 10.

You may be surprised to see Kansas City and Green Bay still not near the top of the DVOA ratings, considering that they are on top of a lot of power rankings around the Internet. The Chiefs, in particular, are current betting favorites to win the AFC and put up a big statement win against the Los Angeles Chargers last Thursday night. Well, it may have been a statement but how big a win it was depends on how you are looking at things. It certainly was big in terms of how meaningful it was to the playoff picture and Kansas City’s chances to win the AFC West. But an overtime win is a close win, not a “big” win, in terms of how much it means in the DVOA ratings.

This gets to one of the most important aspects of the DVOA system: it is completely agnostic about wins and losses. DVOA is looking how well a team played compared to the league average baseline on a play-by-play basis, and wins and losses only matter in that wins usually represent good performances while losses are bad ones. Obviously, wins and losses matter, since that’s the whole point of playing the games, but they don’t tell us as much as play-by-play performance when it comes to how good teams are going to be going forward.

The Chiefs get 18.4% DVOA for this game, and the Chargers are at 17.3%. I’m actually surprised that the Chiefs-Chargers game came out so close despite the overtime result, because Kansas City outgained Los Angeles 7.3 yards per play to 5.5, and the turnovers and success rates were equal. The game drew closer because of a surprising special teams result, as the previously strong Kansas City special teams had a bad game (-10.2%) and the previously terrible Chargers special teams had a good one (14.1%). That made up the offensive and defensive difference between the teams.

Another very close game this week was Green Bay over Baltimore, where the Packers pulled out a win in part because the Ravens went for 2 and the win and failed. (2-point conversions, by the way, are not included in DVOA because they are so rare.) This game had 10.8% DVOA for Green Bay and 3.7% DVOA for Baltimore. That rating for Green Bay is very close to the Packers’ rating for the entire season, which is currently 11.6%. The Packers went up a little bit in DVOA this week because of shifts in opponent adjustments but overall this win had no effect on their DVOA rating despite making the Packers the first team to clinch a playoff spot and giving them the inside track on the No. 1 seed in the NFC. Despite having a lower DVOA than their NFC rivals, Green Bay now wins the No. 1 seed in two-thirds of our playoff simulations.

There’s been a lot of criticism of DVOA for having Green Bay too low this year, so let’s talk about them some more. The Packers are an interesting team because they started with a horrible game against the Saints in Week 1 and have played well the rest of the way… but not too well. Here’s the Green Bay week-to-week graph. You’ll notice that the Packers have DVOA above average for every single game since Week 2, including their two other losses (Week 9 to Kansas City and Week 11 to Minnesota). In fact, if you removed the Week 1 game, the Packers would have a variance of 2.3%, which would not only be the lowest for any team this year but the lowest ever measured in Football Outsiders history.

The best teams in DVOA tend to build their ratings with dominant victories. The Packers don’t have many of those. Their 17-0 win over Seattle in Week 10 is certainly dominating on the scoreboard, although the DVOA for that game is surprisingly low (33.4%). A Week 3 win over San Francisco is Green Bay’s only game over 50% DVOA. By comparison, the Bills and Rams each have five games that strong while four other teams have three of those games: Dallas, New England, San Francisco, and Tampa Bay.

It’s not like the Packers’ close games are “flukes.” As noted above, they come out with a positive DVOA for every single one of their wins. They have a number of mid-level wins over mediocre teams, beating Pittsburgh, Chicago, and Washington by two scores apiece around midseason. They just don’t have the big wins that are typical of a team that starts the season 11-3.

A good way to look at this is with something simpler than DVOA: points scored and allowed. If you read Football Outsiders regularly, you know we convert points scored and allowed into a win projection using what we call Pythagorean wins. Right now, the Packers are outperforming their Pythagorean projection by more than any other team in the league. It’s not a historic amount that’s going to come close to setting any records, but it’s a lot. The Packers have outscored opponents by 57 points which projects to 8.5 wins, ninth in the league. That’s a 2.5-win difference with their actual record, which is pretty big. And here’s the thing: This is not just because they lost to New Orleans 38-3 on the opening Sunday. If you take that game out of the equation, the Packers still lead the league in Pythagorean overperformance, just by a smaller margin. These are the six teams that currently are outperforming Pythagorean projections by at least one win:

Here’s a look at the teams on the other side (Seattle and Philadelphia do not include Week 15):

Green Bay Packers fans at this point tend to have a few different responses as to why their team should be rated higher than 10th (DVOA) or ninth (weighted DVOA).

1) Yes, but we have the best quarterback. This does matter! We know that offense is more predictive than defense or special teams. It matters that Aaron Rodgers is so good, it makes sense to trust him to win in the playoffs a little more than you trust a team that has Mac Jones or Carson Wentz under center. Rodgers took a significant lead this week as the best quarterback so far this season by passing DVOA, and the Packers are second in offensive DVOA behind Tampa Bay. That’s why advanced metrics that give extra weight to the quality of the quarterback, such as ESPN’s FPI, will have Green Bay higher than Pythagorean wins or DVOA. However, even ESPN’s FPI has the Packers sixth behind five teams with fewer wins.

2) Yes, but we’re done all of this with some of our best players injured, and some of those players will be coming back from injury soon. This is also true! It’s also not what DVOA is meant to measure. DVOA is not adjusted for every single injury that a team is dealing with. We’re measuring how well teams played on the field with the players they had on the field. The Packers could potentially have Za’Darius Smith, Jaire Alexander, and David Bakhtiari back on the field by the time we get to the playoffs. But those men were not part of the team for most or all of this season, and it is the team that was on the field this season that ranks 10th in DVOA. As for our playoff odds simulation, for the most part we only adjust the ratings we use in that simulation for quarterback changes. We’ve found that changes at other positions just don’t have the same easily measurable effect as a change at quarterback. The Packers rating used in the playoff odds simulation is already boosted, in that the offensive rating does not include the game started by backup Jordan Love.

3) Don’t these advanced metrics underrate Green Bay every year? Clearly the Packers are doing something that is winning more games than these advanced metrics can pick up, right? This is an interesting argument. The Packers have outperformed their Pythagorean projection for three straight years now, ever since Matt LaFleur was hired as the head coach. The Packers went 13-3 each of the past two years but had only 9.8 Pythagorean wins in 2019 and 11.2 Pythagorean wins in 2020. They haven’t outperformed DVOA to the same extent, but there’s no doubt their 13-3 record in 2019 was a lot better than their No. 9 rank in DVOA. Last year, the Packers were third in DVOA, which is much more commensurate with a 13-3 record.

It’s possible that there’s something about Matt LaFleur’s coaching which enables him to consistently win close games and outperform the Pythagorean projection. It’s also possible that the Packers just happened to have flipped a coin heads three years in a row, which isn’t really that stunning.

Or… it’s also possible that there’s something about Aaron Rodgers at quarterback that leads to the Packers winning close games and outperforming the Pythagorean projection. Most of Rodgers’ teams have outperformed their Pythagorean Projection, although usually by less than one game. The same thing is true of most of Peyton Manning’s teams and most of Tom Brady’s teams, so there certainly may be something to the idea that having a top quarterback enables you to win more close games. However, Peyton Manning’s teams were not routinely underrated by DVOA. (There are a couple of seasons such as 2009 where the Colts didn’t end the year as high in DVOA as you would expect, but that’s because of games where they sat Manning and backups dropped their rating.) Neither were Tom Brady’s teams or Joe Montana’s teams. So if there is something about the best quarterbacks that leads to them outperforming the Pythagorean projection, I think that DVOA is picking that up, and it’s not the reason why the Packers are only 10th in DVOA this season.

One thing that DVOA is picking up is just how bad the Packers are on special teams. They are now dead last at -6.5%. Someone asked me this week if a team with special teams this bad had ever won the Super Bowl, and the answer is no. The 2006 Colts had the worst special teams DVOA of any Super Bowl champion at -3.6%. The 2009 Saints, 2020 Buccaneers, and 2010 Packers were also below -2%. But just because a team with special teams this bad has never won the Super Bowl doesn’t mean it can’t be done. As mentioned above, special teams is less predictive than offense, and offense is where the Packers shine. Special teams is a weakness, but not necessarily a fatal flaw.

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Here is the Football Outsiders Top 16 through 15 weeks 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.)

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.

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.