Tuesday, March 27, 2007

2006 Third Down Efficiency

Brian at mgoblog was kind enough to post the third down data from every I-A school again this season. And it's all in a handy graphical format. I'm going to take a look at the NC State offense here, but you can find a lot more at mgoblog (2005 numbers, and defensive numbers as well). While you're over there, take a look at UNC's weird third down efficiency graph. The Heels were well below the national average in 3rd-and-less-than-5 and well above it in 3rd-and-everything-else.

I'm going to start with the Wolfpack's third down efficiency graph; here's a brief explanation from Brian:
First: Third down efficiency. The thick line in the center is the NCAA average (e.g., approximately 68% of third and ones were converted last year). There is a second line that represents an individual team's third down efficiency. Where there is a gap between the lines that gap is filled in with either red or green depending on whether it is "good" or "bad". Being above the line is good for offenses--you convert more often. Being above the line is bad for defenses--you are converted upon more often. You want to see a lot of green in these graphs.

(click images below for larger versions)

NC State converted 3rd-and-shorts at a rate higher than the national average, but that's it. We sit below the average at every other distance, and we especially struggled to convert in the 8-11 yard range. Even so, we showed some definite improvement over 2005. We were 6-of-16 on 3rd-and-1 last season (a conversion percentage that was waaay below average), 13-of-16 from that same distance this year (well above average). I don't have a good explanation for that. Better play calling? Improvements to the offensive line's technique?

Next up is third down distance. This graph illustrates what percentage of NC State's third downs occurred at the various distances listed on the x-axis. The green and red don't indicate "good" or "bad," just above or below average.

In 2005, State's offense had more third downs between 5-10 yards than average and fewer third downs between 1-5 yards than average. In 2006, that basically flip-flopped, with the offense getting a lot more third down opportunities between one and five yards. In particular, a whole bunch of 3rd-and-5s.

One reason for the change in third down distribution between 2005 and 2006 is probably play selection: we threw the ball on first down 49.2% of the time in '05, 59.6% of the time in '06.

This last graph displays the raw numbers. You can see, for example, that the Wolfpack had 19 3rd-and-5s: