Pinned Inside The 10

10/06/2014 Matt Chambers 0 Comments

It took a bit longer to finish this visualization than originally anticipated. I found a really cool dataset from Advanced Football Analytics that contained 10 years (2002-2012) of NFL play-by-play data. Unfortunately, it appears AFA has removed the file since I downloaded it. Once I had the file in hand, I started looking at the data and immediately I started thinking back to a question I've always wanted to answer. What's the impact of a safety?

Nothing gets the defense pumped up like sacking the quarterback in the end zone for a safety. It results in two points and a free kick to the opposition, and it demoralizes the offense. What I wanted to find out is what is the average number of points given up on the ensuing drive after the free kick. The total points given up due to a safety is the two points plus the value of the ensuing drive. Then, I wanted to see how many points are given up if you punted inside the ten yard-line instead.

What I found is that inside of the three yard-line less points are surrendered on average with a safety than a punt. Now, I realize that the sample size for safeties is not enough to say it is statistically significant, but the average amount of points surrendered is lower. A safety results in much better field position than a punt, so you are basically trading the two points for a gain in field position. Take a look at the interactive visualization to explore the impact of punts and safeties.