The NFL has one of the most obvious home field advantages in all of sports – the fan noise. Quarterbacks read defenses and then need to be able to effectively communicate to the rest of the offense after they line up. Things like telling lineman to pick up blitzers all the way to changing the entire play based on what the defense is showing. As a fan in the stadium, you remain quiet when your team is on offense but get really loud when the other team’s offense gets to the line – this has a material impact on the game. With COVID-19 running rampant in the United States, NFL teams have not been able to pack their stadiums with screaming fans. However, the NFL has allowed teams to decide how many fans they allow in their stadiums which I believe gives certain teams an advantage. Teams like my Green Bay Packers have elected to keep their stadiums completely empty while other teams, like the Dallas Cowboys, have filled their stadium with 20,000+ fans. The goal of this analysis is to demonstrate whether the NFL not having a uniform attendance policy has led to teams risking public health for a competitive advantage. Using Coegil’s powerful data science tools, I was able to perform my analysis much easier than if I was just using a spreadsheet.
I pulled two sets of data from Pro Football Reference: game results and attendance from 2010 through the current season using a notebook. I looked at three statistics – points scored, offensive yards, and a games point differential. The goal was to look at those three stats and see how they were impacted by whether or not a team was home and how filled the stadium was. To keep things simple, I created a metric for how much a stadium was filled that assumed every stadium had a capacity of 60,000 and compared the attendance to that number (if the attendance was greater than 60k, I recorded it as 100% filled) since we really only cared about buckets – (was the stadium empty, full, half filled).
Before exploring home field advantage in 2020, I wanted to take a look at how home field advantage has changed over time. I created these charts to help visualize the league trends as well as these ones to visualize the team trends. I noticed a few interesting things.
1 – Offensive numbers are way up in 2020 compared to previous years – both yards and points scored. I believe this makes sense given how the offseason was this year. Camp was mostly held remotely, teams had few in person practices, and there were no preseason games. All of these things would result in defenses being under prepared and would result in offenses over performing.
2 – It looks like home field advantage was non-existent in 2019 and 2020 despite being pretty consistent between 2010-2018.
Despite the lack of a concrete home field advantage in 2019, I still wanted to see if there was any advantage for teams in 2020 based on their attendance. I ran some basic analysis in my notebook and build a chart to see if there was any correlation between stadium capacity and home field advantage. Unsurprisingly, there does not appear to be any.
It appears that my initial hypothesis was incorrect and there is no competitive advantage for allowing fans into the stadium. While doing this analysis, I stumbled upon something that I find more interesting – home field advantage may be diminishing in the NFL. Whether it is offenses getting better at non-verbal communication or something else, it will be interesting to see if that trend continues in the 2021 season when stadiums are back to full capacity with screaming fans.