With the Chiefs and Bucs set to face off in the Super Bowl on Sunday, now would seem to be a great time to look back at the 2020 NFL season.

Due to the effects of the COVID-19 pandemic, this was far from your typical season. However, when dissecting early trends from it as the midway point, it was quite interesting how much it aligned with what you’d expect from normal seasons.

Now, however, we have a far greater sample size, and can officially answer our question: what correlated to winning in 2020, and how does it compare to data from years past? That will be the focus of today’s piece, with a special bonus: we will also look at the luckiest and unluckiest teams in terms of point differential, points scored, and points allowed!

Do these Super Bowl teams represent the norm of success in the NFL? Or are they a barrage? Let us crunch the numbers?

What Correlated To Winning?

In the past, offense has been proven to be much more predictive that defense when it comes to overall team success. Yet, people still can point to the Rams, Steelers, and Washington Football Team as organizations to prosper with strong defensive play. Does this mean that the tides are shifting in favor of defense? Not quite:

In essence, a point scored was 1.19 times more valuable than a point allowed. Overall, these numbers are closer to one another in the past, meaning that defense may have played a wider role, but that may have something to do with the wider difference in defensive play this season. Teams like the Jets, Jaguars, and Lions were poor all around, with teams like the Bucs, Rams, Saints, and Packers were all top-ten graded defenses from PFF but also ranked in the top twelve in offense grade.

Teams with top-ten defense grades and below-average offenses included the Bears, Broncos, Steelers, and Washington Football Team. Only Pittsburgh, who rated above-average in points scored due to turnover luck and regressed down the stretch, finished with a winning record. On the other hand, inconsistent play didn’t limit the Chiefs, Titans, Browns, and Bills from doing so. Even the Vikings and Texans, who were top-ten offenses with long records, did so with poor turnover luck, one-score game luck, and two of the most difficult schedules in the NFL by pretty much any metric.

Defense could have played a greater role in this season’s outcomes, but there is plenty to suggest that a) this is a mirage and b) it is unstable. Thus, those who benefited from strong defensive play this season are likely to regress next season. By estimating each team’s point differential by offense and defense grade, here are the teams likely to do just that.

Lucky Teams

1. Ravens
2. Dolphins
3. Cardinals
4. Saints
5. Bears

The Ravens, Dolphins, Saints, and Bears all benefitted from a significant amount of turnover luck and relied a lot on defensive play, making them strong candidates to regress next season. As for the Cardinals, their point differential is boosted by a successful Hail Mary and a ten-point comeback against the Seahawks based highly on a leverage penalty, so even though they relied more on their offense, they simply were on the right side of variance. It is also worth noting that the top-three teams on this list benefitted from schedules rated amongst the league’s easiest, which is something they won’t benefit from as much next season.

Unlucky Teams

1. Jets
2. Browns
3. Broncos
4. Jaguars
5. Vikings

No team is supposed to be as bad as the Jets and Jaguars were last season, so let’s throw them out. The Broncos, meanwhile, had the league’s worst turnover margin, which is why they are certainly a candidate for positive regression should they upgrade at the quarterback position. The Vikings, additionally, return all the pieces of their top-ten offense from a year ago, and are certainly a playoff contender if they can have similar success next season (not a certainty by any means).

The Browns have to be the most interesting team on this list. Many labeled them as a “fraud” due to their negative point differential, but it appears as though their point differential never accurately reflected them. Considering it was inflated by two blowout losses to the Ravens and Steelers, this makes sense, in addition to them squandering a huge lead in garbage time to the Titans. With an offense that turned the corner in the second half of the season, they’re a strong bet to be amongst the AFC’s top teams next season.

What Correlated To Strong Offensive Production?

If offense, as normal, is what wins games, then it behooves us to identify the most efficient way to maximize the amount of points scored from a roster-construction perspective. As per usual, the quarterback’s effect on an offense cannot be overstated:

How can you look at this scatterplot and not feel for Deshaun Watson? In all seriousness, just by a glimpse of this plot, the benefits of an elite quarterback are incredible. The best quarterback led the most productive offense, and the worst quarterback led the least-productive offense- all was right after all?

Outside of the quarterback, it is clear what position moves the needle:

Good quarterback play + dynamic receivers = a lot of points. That is all. The thought is that a quarterback needs to be protected by a strong offensive line, but, in reality, having a receiver who can gain instant separation is far more valuable. Football is won in the perimeter, rather than the trenches.

The rest of the results are rather wonky. Now, rushing grade doesn’t exactly equate with rushing EPA/play, and it is worth noting that amongst the teams with the best rushing grades were:

• Titans
• Vikings
• Packers
• Browns
• Bucs
• Chiefs

All of these offense featured quarterbacks with passing grades above 84, and with how unstable rushing production is, the Colts and Saints need stronger quarterback play, while the Titans and Vikings should be more open to passing the ball more frequently on early downs. The two teams with top-ten rushing grades and below-average passing grades? The Patriots and Broncos, who offenses should not inspire to be.

Pass protection was much more significant than it had been in the past, though this is likely due to a small sample size. Then again, the Titans, Vikings, and Seahawks all prospered with below-average pass-protecting offensive lines, while extra pass protection surely didn’t help the Washington Football Team, Pittsburgh Steelers, or Detroit Lions much this year.

With a great emphasis on quarterback play and receiving talent, we can now project how many points per game each team scored. In the end, these teams overachieved/underachieved the most offensively:

Lucky Offenses:

1. Ravens
2. Steelers
3. Dolphins
4. Colts
5. Saints

We discussed earlier than the Steelers and Dolphins benefitted from turnover luck and strong field position, which is also true of the Ravens. Meanwhile, the Colts and Saints relied heavily on their rushing attacks, which may have worked this season, but likely won’t next season. Interestingly, with Phillip Rivers and Drew Brees set to retired, they’ll look to avoid offensive regression with new quarterbacks under center.

Unlucky Offenses:

1. Giants
2. Chiefs
3. Texans
4. Browns
5. Jets

The Giants got strong play from Daniel Jones, but for whatever reason, it never showed up in the way of results. Additionally, an offense led by Deshaun Watson should score much more than the Texans did, and any offense should score more than the Jets did.

The other two are far more intriguing. If the Chiefs offense was unlucky this season, what happens when they hit on the right side of variance. Meanwhile, the Browns not only were unlucky overall, but deserved to score more points than they did. I’m quickly becoming the top member of their hype team.

With our new play-caller metrics, we can also see how much coaching has an effect on an offense, which is quite substantial:

I’ve said for a while that an offensive play-caller in the second-most person on an offense, and this backs this up. Overall, we see a pretty strong linear relationship between scoring a lot of points and having a top-notch play-caller. It isn’t a coincidence that the league’s best play-caller, Andy Reid, is currently in the Super Bowl, with Matt LeFleur’s Packers and Brian Daboll’s Bills possessing two of the highest-scoring offenses in football. For a team like the Falcons, who upgraded tremendously to Titans offensive coordinator Arthur Smith as their head coach, positive regression can be expected.

What Correlates To Defensive Production?

I’ve been a major proponent of the idea that coverage is far more valuable than one’s pass rush, and as per usual, that was backed up by this year’s data:

Defending the pass is far more important than defending the run, but that comes by being sound in pass coverage. In fact, is this evidence that we should focus more on run defense on the defensive line? A lot of great work has been done to show the value of run-stopping interior players, who allow defensive coordinator to invest less resources against the run, and with pass-rush production far more easily schemed with blitz packages (it is much harder to hide liabilities in the secondary), this is further evidence that investing heavily in one’s pass rush is a bad idea. I’m sure the Eagles, Cowboys, and Browns (above-average pass rushes with poor coverage grades) would agree with that. Conversely, a poor pass rush didn’t stop the 49ers and Ravens from being amongst the better defensive teams in the NFL.

With that in mind, the luckiest/unluckiest defenses were:

Lucky Defenses

1. Giants
2. Cardinals
3. Raiders
4. Jets
5. Eagles

Man, the Raiders and Jets should have allowed more points than they did and still were abysmal in that area. That isn’t a great sign moving forward. The Giants, Eagles, and Cardinals all benefitted from easier schedules, but facing more difficult quarterbacks in 2021 could prove to be problematic without improvements in the secondary. Then again, they weren’t exactly lighting the world on fire anyways.

Unlucky Defenses

1. Vikings
2. 49ers
3. Broncos
4. Packers
5. Titans

Outside of the Broncos, none of these defenses were strong when it came to rushing the passer, and pretty much of all of them suffered from poor variance overall (either turnovers, red-zone luck, or third-down luck). The 49ers already were a top-ten defense this season and will be much healthier next season, and the Broncos were hit hard due to poor field position from turnovers. Plus, with how prolific the Titans were offensively this season, them hitting on the right side of variance (awful on third downs) in unstable facets of defensive play could lead to them being an even more complete team next year, though I’m not sure it would make much of a difference anyways.

The play-caller on defense has a greater effect than they do on offense, which makes sense since defensive stars generally move the needle less (more on that in a future article). The 49ers were an “unlucky” defense, but replacing Robert Saleh may prevent them from making good on positive regression, while the Rams are likely to regress significantly without the services of this year’s top-rated play-caller, Brandon Staley. Overall, continuity and coaching prompt up defensive play as much as talent (defensive grade to points allowed r^2= .601), which is precisely why heavy investments on the defensive side of the ball in free agency, trades, and the draft are often illogical.

Who Were The Luckiest/Unluckiest Teams Overall?

Since one season is a small sample size, I estimated each team’s point scored and points allowed per game by historical data, which is statistically optimal.

With these estimations, we can now estimate each team’s point differential for the season based on priors, grading profiles, their play-callers, and a proper weighting system.

No surprise here. The Ravens and Dolphins clearly benefitted from turnover luck, while the Saints, Steelers, and Colts need improved offensive production to sustain their success. On the other side of the spectrum, the Lions, Jaguars, and Jets were REALLY BAD this season, so, in my mind, the Vikings were the biggest underachievers this season.

Overall, these teams are the most noteworthy, as they go through a key number in terms of point differential:

• The Dolphins were fundamentally a negative-point differential team, as were the Cardinals. Both were middle-of-the-pack teams that were often treated and prices as true playoff teams.
• The Ravens were not the league’s best team, as their point differential suggests, and they need to be aggressive in terms of upgrading their passing offense.
• The Steelers’ regression in the second half of the season suggests they shouldn’t be optimistic about their chances of contending next season.
• The Bears should not buy into their 8-8 record as a reason to go all-in in 2021, which seems to be exactly what they are doing.
• The Vikings and 49ers were positive point differential teams in estimation with negative point differentials. Both are strong values in terms of banking on to be better this season, particularly the 49ers, who will be much healthier and perhaps will even upgrade at QB.
• I continue to be in awe of the Browns’ potential in 2021.
• Perhaps the Jets, Jaguars, Lions, and Bengals will regress to the mean in 2021! There is hope!
• The Chargers are a strong bet to be a playoff-caliber team with Justin Herbert in his second season and better luck with a new head coach.
• The Broncos were better than their point differential showed and an improved quarterback would be huge for them.

As for the Super Bowl teams, the Bucs slightly overachieved their estimated point differential while the Chiefs slightly underachieved. The main difference between these teams is Kansas City’s offensive play-calling, and it will be interesting to see a) if that plays a role in Sunday’s game and b) the Chiefs are even better next season.

Overview

Overall, this season was a little wonky in terms of minor offensive correlations, and defense was slightly more “important”. Yet, this was likely statistical noise, and moving forward, teams who realize this will be the ones who are able to sustain success.

On the other hand, the quarterback reigns supreme, with the receivers corps right behind. When the four final teams are the Chiefs, Bills, Bucs, and Packers, that is something that should already be true, but the numbers back it up regardless.

Also, we need to continue to fade the idea that a pass rush makes a significant impact on a game compared to a team’s coverage unit. Focusing on a collection run defenders on the defensive line who allow a defensive coordinator to not invest resources to stop the run, while accumulating depth in the secondary, is the way to build a strong defense. In the end, though, the play-caller also plays a huge role and must put his players in the right position to succeed- he must not invest resources to stop the run, scheme pressure, and tailor his coverages to his opponent.

Overall, the Browns, Vikings, 49ers, Broncos (pending a QB change), and Chargers would appear to be the teams set to positively regress next season, with the Dolphins, Cardinals, Steelers, Saints, Colts, and Bears the likeliest teams to get worse; the Ravens dealt with injuries and are talented enough to win in sustainable facets of play. Also, keep an eye on the Chiefs, who should be even tougher to deal with next season, based on the numbers.

It is critical to not overreact to one season, unless the data backs up historically-proven data. Thus, I’m assuming next season, with normal training camps, could fade even more for offense. In general, though, a major issue with defensive play is that it is difficult to predict from game-to-game, and also is reliant on the opponent much more than the other way around. Teams who realize this, such as the Chiefs and Packers, are the ones who generally have been able to enjoy sustained success. Hopefully, other teams realize this as well.

Quarterbacks, receivers, and a strong coverage unit; football really is won on the perimeter. Will any team dare to go away from the norm and stop investing heavily in the trenches? We can only hope so!