Brian Cook posted this in response to that Dave Curtis piece on third down conversion rates I linked to yesterday:
… Just looking at third down rates is goofy because first and second down contribute to the distance you have to go—you’re really looking at “first and second and third down conversion rate,” which is fine if you want to look at that. Just don’t make it seem like third down is really really important when your number doesn’t control for the effects of first and second.
Well… yeah, pretty much. I mean, it’s hard to argue with Brian’s overall point, but I ‘m not sure that explains everything about Curtis’ numbers. What if a defense is bad about preventing conversions on third down and seven or more yards, or if an offense has trouble picking up first downs on third and short yardage situations? Those are both cases where the contributions on first and second downs Brian contemplates don’t have as much of an impact on drives.
There’s no way I’ve got the time to run down an analysis of every team Curtis referenced, but I was curious how much the 2010 Georgia results are in line with Brian’s observation.
A look at Georgia’s stats at cfbstats.com discloses plenty of third down information. First, the big picture:
- offense third down plays: 64 rushing; 99 passing; 163 total
- defense third down plays: 74 rushing; 98 passing; 172 total
Next, here are the conversion rates for various distances.
- rushing offense: 3 yards or less, 18-30; 4-6 yards, 2-14; 7-9 yards, 1-14; 10 yards or more, 1-6
- rushing defense: 3 yards or less, 21-35; 4-6 yards, 6-13; 7-9 yards, 3-11; 10 yards or more, 2-15
- passing offense: 3 yards or less, 10-18; 4-6 yards, 13-32; 7-9 yards, 7-26; 10 yards or more, 5-23
- passing defense: 3 yards or less, 6-10; 4-6 yards, 8-27; 7-9 yards, 12-29; 10 yards or more, 11-32
Did you catch the anomaly? If not, let me repeat the data with emphasis.
- rushing offense: 3 yards or less, 18-30; 4-6 yards, 2-14; 7-9 yards, 1-14; 10 yards or more, 1-6
- rushing defense: 3 yards or less, 21-35; 4-6 yards, 6-13; 7-9 yards, 3-11; 10 yards or more, 2-15
- passing offense: 3 yards or less, 10-18; 4-6 yards, 13-32; 7-9 yards, 7-26; 10 yards or more, 5-23
- passing defense: 3 yards or less, 6-10; 4-6 yards, 8-27; 7-9 yards, 12-29; 10 yards or more, 11-32
In other words, if you were an offense facing last year’s Georgia defense, you stood a much better chance of converting on third and long passing plays (37.7%) than you did on third and medium ones (29.63%). Some of that is the result of Georgia playing some truly exceptional defense in third down and medium distance situations (opposing passer rating: 53.42!), but, still there’s something going on with the longer distances (note that Georgia’s conversion rate on offense in those circumstances was under 25%). Any ideas about what the cause(s) for that might have been?
Get The Picture 