Each Turnover Worth a Touchdown

NOTE: I know I'm getting ahead of myself, as this post corresponds to 2nd order win%, but this is what I've been thinking about for days.

In our quest to identify true team talent, one of the questions I have been thinking about is how much is a turnover worth? How many points can a team expect to lose by turning it over. Not just in the points off the turnover given the good field position, also the lost scoring opportunity, the game changing ability, and the momentum shift. These all contribute to lost points.

To estimate the value of each of these turnovers, I took data from my new favorite site http://pro-football-reference.com/ on each of the past 5 years. I took each team's full season data, especially considering Point Margin (Pts Scored - Pts Allowed) and Turnover Margin (Takeaways - Turnovers).

Then I plotted on a scatter plot the two values. The regression line will give us the answer we're looking for:

There! Over the last 5 years, a turnover has been worth 7.615 points over a full season. Thats almost a point every two games! Its also more than most touchdowns. This gives us a starting point to move forward in our analysis of individual NFL contributions. If a running back fumbles the ball, -7.615 points immediately... boom baby.

I'll call this value TOp (Turnovers in points), thus TOp = -7.615.

In defense of TOp, I believe that margins are the best way to estimate this because of the effects on both the opponents score and your own. I also believe in including non-offensive scoring because momentum is also part of this analysis. Turnovers affect the very mindset of the football players. Thus we must use all-encompassing values that are expected to go towards the mean over time. I believe 5 years is enough time, although, we can add that to the list of todo posts: When do these stats stablize?

Interestingly, the 4 years preceding 2009 saw relatively stable value for TOp, but in 2009, that value jumped to 10.123:

I wonder what was the cause of this. It seems turnovers were especially important last year. This is interesting, but a story for another time... 

The bigger picture:

This value of TOp will help us get ePM (Expected Point Margin) which is the key to 2W%, the 2nd order winning percentage.