Tuesday, June 17, 2008

Point Values Of Penalties And Turnovers

Wolfpack fans have been harping on penalties and turnovers for years now: if we're going to turn this thing around, we've got to stop shooting ourselves in the foot so frequently. Thanks to some outstanding work with play-by-play data from the 2007 college football season by Rock M Nation, we can actually look at the specific cost of penalties and turnovers in terms of points (hat tip: EDSBS):


Average point value of a defensive penalty: 0.914 points
Average point value of an offensive penalty: -0.229 points

Suggests that defensive penalties are more costly than offensive ones...


Average point value of a turnover: 3.17 points

Using the PBP, Rock M Nation calculated the number of points a team could expect to score based on its field position, and he used those averages to find the above values. More here.

Last year, I broke down the penalties committed during the 2006 season by NC State and ended up with these numbers:

        Pen     %Tot
Off 50 58.1
Def 25 29.1
SPTms 11 12.8

Plugging in those point values (which are derived from a different season, so this is definitely a rough estimate), the cost in terms of points looks like this:

Offense: 50 penalties x -.229 pts = -11.5 pts
Defense: 25 penalties x .914 pts = 22.9 pts

So 75 penalties made for a net cost of about 34 points in 2006.

As for turnovers...I'm not sure I really want to think about that.