By Eric Rynston-Lobel
This time last year, Northwestern was on the cusp of its first Big Ten West title. Now, the Wildcats are on the cusp of their worst season in the 14-year head coaching career of Pat Fitzgerald.
How did this happen? A team that won nine games last year brought in a five-star quarterback to take the reins from four-year signal-caller Clayton Thorson. But it seems that Thorson’s legacy has only been enhanced this season despite having not played a snap.
Following the ‘Cats 34-3 drubbing in Bloomington on Saturday, it doesn’t seem as though things will get any better this season. But how did we even get here?
I’m going to make the case that the statistical principle of regression to the mean can help explain why. Sure, it’s far from being the only reason why this team has struggled mightily, but it can definitely help with our understanding of this disastrous season.
What is regression to the mean?
For those unacquainted with this statistical phenomenon, regression of means is a theory which basically states that an extreme event is likely to be followed by an event that’s less extreme. Taking this out of a football context, consider the following examples of this theory:
Wolfgang Mozart was a phenomenal musician. His six children were still incredibly talented when it came to music, but they were not as great as their father.
A couple (dad is 6’8 and mom is 6’4) have children. Their children are likely to be taller than average, but shorter than their parents because their parents are an extreme example of what is means to be tall.
Now, we can turn back to sports and think about something I’m sure many of you have heard of: the Sports Illustrated Jinx. This is the phenomenon that when an athlete or a team is featured on the SI cover, they subsequently underperform in the near future. Though there are many examples of this, let’s look at a recent instance.
In September of 2017, the Los Angeles Dodgers were featured on SI’s cover with the question ‘Best. Team. Ever?’ posed. On August 25, the Dodgers were an astounding 91-36, on pace to tie the Seattle Mariners’ single-season regular season record of 116 regular season wins. But instead, the team finished the regular season losing 22 of its 35 games and ultimately lost to the Houston Astros in game seven of the World Series.
You could say, ‘well, a team like Seattle did win 116 games in the regular season, so they didn’t regress to the mean.’ And yes, that’s true. But how many teams have ever won 116 games in a regular season? Just one. It’s not typical because it’s an extreme outcome for a Major League Baseball season.
Now, back to the 2019 Northwestern Wildcats.
Good defense. horrific offense
Last season, the Wildcats’ offense was ranked 94th out of 130 FBS teams per S&P+. In 2017, the offense was 60th. This year, it’s 130th.
What’s interesting to note about the 2017 and 2018 seasons was how massively Northwestern differed in expected wins compared to its actual number of wins. Last year, the ‘Cats had the second largest differential in second-order wins. This is a metric that basically calculates how many wins a team is expected to have. In 2018, that number said the ‘Cats should have won 6.2 games. Instead, they won nine.
In 2017 when NU was 10-3, second-order wins suggested that total should have been eight. This difference of two was tied for fifth largest among the 130 FBS teams. In other words, the ‘Cats have overperformed the last two years according to this metric.
While S&P+ won’t have the numbers for 2019 until the season ends, it’s rational to assume Northwestern will have underperformed in the second-order wins differential.
This is where regression to the mean comes in. The last two seasons, Northwestern was the 91-36 version of the Dodgers. Now, they’re the September version. What they are doing this year is well below the mean, while what they did the last two years was well above it.
The point is, Northwestern could have easily been 6-6 last year had a couple of the five one-possession wins not gone its way. Similarly in 2017, the team won four one possession games. If a couple plays go a different way, that team is 8-4, not 10-2.
This year, the same logic can be applied in the opposite manner. Sure, the offense has been worse than horrible since the Nebraska game on October 5, but that’s not to say the team couldn’t have won that game. A case could also be made that they should’ve won the season opener at Stanford. If that happened, the ‘Cats, though still far from where they’d want to be, would be 3-5 and certainly within striking distance of another bowl appearance.
Their method of winning, though, just doesn’t seem sustainable. Obviously, a team would rather win a game by more than one possession, but having a +14 point differential like the ‘Cats did last year typically doesn’t translate to a nine-win season.
The tide was bound to turn eventually. And 2019 has been that year.
Isn’t the defense still elite?
Until this week, the answer would be yes. Indiana’s potent offense gave Mike Hankowitz’s crew a difficult time. But even still, the ‘Cats boast a top defense in college football.
The problem, though, is that the defense can only do so much. As I discussed in my story last week, Fitzgerald has stressed the unit’s need to “force” turnovers. But after some investigation, it doesn’t seem fair to ask a defense to “force” turnovers because of the number of components outside of the players’ control.
Additionally, when the defense is on the field for as much as they’ve been this year because of the floundering offense, it’s reasonable to expect them to fatigue as the game and season progresses. Again, there’s only so much they can do.
The offense has been the scapegoat most of the year and rightfully so. But at the same time we need to consider how the team still won games it probably shouldn’t have last year with a poor offense. Regression of means says the poor offense was bound to catch up to the ‘Cats eventually.
That’s not to say the positive results last year are the cause for the poor outcomes this year. However, not much has changed in the offense, and more generally the team’s philosophy of winning close games and creating turnovers. It’s just not a sustainable strategy to winning.
If Northwestern wants to take that next step and become a perennial contender in the Big Ten, it needs to rethink it’s offensive strategy. Sure, years like 2017 and 2018 where winning close football games partially due to timely turnovers can happen. But 2019 is a prime example of how things can just as easily head in the opposite direction.
In 2017 and 2018, the ‘Cats were much closer to the fire than it may have realized. This year, they’ve finally gotten burned.