The winds of change are blowing across the NFL. The old defensive guard is gradually giving way to the young offensive guns. For the best or for the worst ?
With 7 vacancies, the position of NFL head coach will be highly sought after this offseason. The start of 2024 marked the end of an era with the departure of two of the most experienced coaches in the league in Pete Carroll and Bill Belichick.
Totally opposite profiles in the management of a workforce, they nonetheless embodied the same archetype of the defensive head coach. These layoffs are part of an NFL that seems more than ever seduced by the offense, with the regular recruitment of coordinators from the Shanahan tree.
This paradigm shift raises a well-known question for teams without a thinking head: do you need a defensive or offensive head coach?
Methodology
For this article, the list of head coaches between 2005 and 2023 was retrieved. Depending on their past as coordinator, a profile was assigned to each coach: offensive or defensive. For the few coaches for whom the path is not obvious (like John Harbaugh who mainly coached special teams), they have been put aside.
In the event that a coach was dismissed during the season, the results were still attributed to him.
State of play
Before diving further into the analytics, it's worth looking at where the NFL is currently. After 15 years of offensive evolution, franchises must adapt. Management received the message. Of the 32 coaches, the share of offensive coaches has increased enormously in recent years, going from 45% to more than 55% in 10 years.
A peak was reached in 2019 following the winning experiments of McVay and Shanahan. But do the results still justify this increase?
Impact of NFL coach profile on results
By comparing the number of victories per coach profile year by year, no trend really emerges. From 2005 to 2023, offensive head coaches averaged 8.23 wins compared to 8.16 for defensive coaches. The benefits alternate by period.
On the other hand, if defensive coaches had the best part between 2022 and 2014, a clear advantage has emerged for offensive coaches since 2020. This is the first time since 2005 that an advantage has been repeated over at least 3 consecutive seasons.
The number of victories does not always quantify the level of a team very well. To further the analysis, the point differential (points scored – points conceded) is a more suitable and much more predictive metric.
The alternation of trends is particularly visible but that's not all. Over the last 4 seasons, teams coached by defensive coaches have never performed so poorly.
The coaches in the Shanahan tree strongly influence these results. The success of these coaches in the league certainly explains some of the results but not all. One of the answers lies in the impact that coaches have on the performance of their squads.
Impact of coaches on offense and defense
Defensive coaches with listless offenses have punctuated football history. The same phenomenon exists for defense, however, not necessarily in the same proportions. To demonstrate this, EPAs per game allow us to quantify the performance of attacks and defenses.
The performances per season of the different squads depending on the coach's profile are compared.
These two graphs include a lot of data but a quick visual analysis gives a trend. On the defensive performance graph the curves follow each other much more than on its offensive equivalent. What does that mean ? What we see is that the profile of the head coach has much more impact on the attack than on the defense. This trend has been reinforced since 2020. Worse since 2021, offensive head coaches have had as much or more success on defense than their defensive counterparts!
Performance by period
The previous observation is clearly more visible by isolating by periods:
The differences in level of defenses of teams coached by offensive or defensive profiles remained fairly stable. On the other hand, for attacks, this gap only increases. Today an offensive coach therefore has a much better chance of making the attack progress without penalizing his defense. A defensive coach, on the contrary, risks penalizing his attack and is absolutely no guarantee of the proper functioning of his defense.
In 2023, 8 of the 10 best offenses have an offensive coach, but so do 5 of the 10 best defenses. 6 of the worst defenses have a defensive coach.
The reason for this discrepancy can be explained several times:
- First, the performance of defenses is much less stable than that of attacks. Many uncertainties impact defensive performance. So a head coach who takes charge of his offense should experience similar success as long as he is on the team (provided the quarterback is the same). A defensive coach will see more variations applied to their preferred squad. Taking this into account, the departure of a defensive coordinator will therefore be less detrimental for an offensive coach than the departure of an offensive coordinator will be for a defensive coach.
- Finally, it is possible that the offensive head coaches of the new wave are generally less conservative than their defensive counterparts and therefore give opportunities to innovative coordinators. This open-mindedness allows them to put in place good defenses.
Conclusion: attack advantage
As always there are no magic formulas in the NFL, the truth of today will not be the truth of tomorrow. It is highly likely that we will soon see a talented defensive coordinator rise to the top job and lead his franchise to the Super Bowl.
But today, the most obvious choice remains to go for an offensive coach.
The fact that the defense is naturally unstable reinforces this idea. So it seems more logical to try to control as much as possible. In addition, the attack today influences the results of a team much more than the defense, which makes it a squad to be favored. But the most important point is that a defensive coach is absolutely no guarantee of a good defense, if you doubt that, ask Brandon Staley.
