Does the NFL preseason matter?

The NFL preseason is underway, which means football is back. It's a time full of overreactions and unnecessary panic attacks. For instance, ESPN's Ron Jaworksi said Arizona Cardinals third-string quarterback Logan Thomas played like a Pro Bowl quarterback. 

These games are important for a lot of players trying to make a team's final roster, but are they vital in determining a team's success in the ensuing regular season? A good preseason could be a sign that a team has significant roster depth. 

The most infamous overreaction occurred in 2008, when the Detroit Lions won all four of their preseason games, and ended up going winless in the regular season. 

I went back six years and found a team's preseason record and regular season record. The findings: 

Teams that won 100% of their preseason games: 39.8% regular season win percentage; 4/11 (36.4%) made postseason.

Teams that won 75% of their preseason games: 54% regular season win percentage; 22/51 (43.1%) made postseason.

Teams that won 50% of their preseason games: 54.1% regular season win percentage; 29/66 (43.9%) made postseason.

Teams that won 25% of their preseason games: 42.9% regular season win percentage; 12/39 (30.8%) made postseason.

Teams that won 0% of their preseason games: 47.5% regular season win percentage; 4/15 (26.7%) made postseason.

The numbers do show that teams that are 2-2 or 3-1 in the preseason do slightly better than their 1-3 or 0-4 counterparts, but just don't win too many games in the preseason. 

The average difference in regular and preseason win percentage is 23.1%, which would be the equivalent of roughly 3.7 regular season games. 

In addition, the correlation between preseason and regular season win percentage is just .085, although there are really only five options for a team in the preseason (excluding Hall of Fame game), while there are 17 possibilities in the regular season (excluding a rare tie). 

Here are all of the instances in graphical form, and keep in mind some data points have more than one instance represented. 

From 2008-13, comparing NFL preseason and regular season win percentage.