After what seems like forever, the NFL is finally back with pre-season play.

And while it's far from the regular season product, for die-hard fans its needed relief that brings early insight into how our favorite teams and players may fair during the upcoming season.



Pre-Season Lessons

How much can we really learn from the pre-season? Starting positions will be won and lost, team dynamics both positive and negative can be illuminated (re: New York Jets) and team and player performance can be highlighted.

But it begs the question, when looking at wins and losses and stat lines from the pre-season, what can the performance of a team in the pre-season suggest about their performance in the regular season?

For example, if the Denver Broncos come out in the pre-season with a 4-0, should one start crowning them as the team to beat?

If we look to last year, we see that the top two teams in the pre-season were the St. Louis Rams and the Detroit Lions - both went 4-0. But their records during the regular season were wildly different - the Lions went 10-6 while the Rams went 2-14.



Digging Into The Stats

While this cursory analysis suggests that pre-season performance is no indication of regular season performance, it's not detailed analysis enough to illustrate whether there is a relationship.

To do this, we decided to compare the winning percentage of the pre-season of the team to the performance of that team in the regular season for every team over the last 10 season, which gave us a sample size of 320 team seasons.

When comparing the records, we found that there was no correlation between the performance of the pre-season to the regular season.

Statistically, the correlation between the winning percentage of a team in the pre-season and their winning percentage in the regular season is 0.0944 - values between -0.1 and +0.1 suggest no correlation between two variables.

There are a few issues with comparing the two records - mainly that the pre-season contains 4-5 games, which limits the number of possible winning percentages creating greater variability in the pre-season winning records. For example, one extra win in the pre-season means a lot more, from a percent standpoint, than in the regular season.

Taking this into consideration, we created buckets for winning percentages in the pre-season and calculated the average winning percentage for the regular season for that bucket.



Pre-season Record of Average Regular Season Record 1.000 0.495 0.750-1.000 0.508 0.500 0.535 0.400-0.625 0.533 0.250 0.442 0.000-0.250 0.450 0.000 0.473



As seen above, there is some indication that having a winning record in the pre-season suggests that the team will do better in the regular season than if they did poorly in the pre-season. But, when the average regular season record for teams with undefeated pre-seasons is below 0.500, one needs to take caution in relying on pre-season records.

What could explain this?

Lack of divisional play

Lack of competitive motivation

Players rotating in and out of the lineup

Use of secondary players

Off-season Rust

In conclusion, based on the analysis above, the pre-season record of a team, provides very little insight into the performance of the team during the regular season - when it counts.