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Evaluating the success of a given rookie class is never easy, as there is no established definition of what success actually means. You could count the number of starts, the number of games played, the number of postseason accolades received or anything else that you can assign a number to.
Yesterday, we went in a slightly different direction and looked at the number of snaps played for each of the last four Dallas Cowboys rookie classes in their first year. We found that the 2011 rookie class played in 8.6% of the total offensive and defensive snaps last year, the highest value of the last four years (2010: 6.9%, 2008: 6.7%, 2009: 1.6%). But is that high enough, or too low? How much is good enough?
I've often heard it mentioned that getting two solid starters out of a rookie class can be considered a good draft. Perhaps not a great draft, but a solid draft at least. Two starters out of 22 total starters equals nine percent, so if your rookie class comes close to that percentage in its share of snaps played, you could argue that the rookie class was equivalent to about two starters.
The other thing I've frequently heard about evaluating rookie classes is that it usually takes three years, sometimes even more, to judge a rookie class, so that's what we'll do today. After the break we'll review the snap percentages for some recent Cowboys rookie classes for their first few years in the league in order to figure out just how much is good enough.
One important note right up front: The snap numbers I use are taken from Pro Football Focus, and unfortunately, their data only goes back to 2008, so I don't have snap numbers for the rookie seasons of rookie classes prior to 2008. But I do have the second year of the 2007 class, the third year of the 2006 class and the fourth year of the 2005 class.
What this allows me to do, is to show how four different rookie classes performed in terms of snap percentage in their first four years in the league. The graph below illustrates what this looks like:
How to read the graph: Take the dark blue bar which represents the 2008 rookie class. In its first year in the league, the 2008 rookie class played on 6.7% of all snaps. That figure climbed to 11.1% in the second year and 11.9% in the third year before falling back slightly in the fourth year to 9.4%.
Now take the green bar, the 2010 rookie class. Obviously, we only have data for the 2010 and 2011 seasons which would be the 1st and 2nd year in the league for that class. In its first year, that class notched a solid if unspectacular 6.9% of all offensive and defensive snaps, but in its second year that value more than doubled to 14.3%, the best value that can be observed using the data we have, and a very promising value for the future.
Equally promising is the 2011 rookie class, marked in purple, which has the highest snap percentage (8.6%) of any of the last four rookie classes.
The 2009 rookie class is the very obvious odd man out, with values of 3.6%, 2.9% and 3.6% in its first three league years. Some people have commented that to be fair, Roy Williams should be included in the numbers for the 2009 class. Well, the numbers in the graph already include Roy Williams! Without him, the numbers would be 1.6%, 0.9% and 3.6% respectively.
The standout class here is without a doubt the 2005 class, marked here in light blue, which returned the highest value of any class in its fourth year with 16.4%. That is the equivalent of 3.6 starters playing every single snap in 16 games. Quite a haul.
Overall, I'd say that the graph corresponds nicely to the way we collectively view the past couple of drafts. 2005 was an excellent rookie class, 2007 and 2008 were solid but could have been better, the 2006 and 2009 classes are forgettable. And with this historical perspective, the 2010 and 2011 classes both look quite promising.
For those who prefer their numbers without all the eye-candy, here's a table with all the data:
| 1st year | 2nd year | 3rd year | 4th year | |
| Class of 2005 | - - |
- - |
- - |
16.4% |
| Class of 2006 | - - |
- - |
3.6% | 7.9% |
| Class of 2007 | - - |
7.1% | 9.5% | 13.2% |
| Class of 2008 | 6.7% | 11.1% | 11.9% | 9.4% |
| Class of 2009 | 3.6% | 2.9% | 3.6% | |
| Class of 2010 | 6.9% | 14.3% | ||
| Class of 2011 | 8.6% |
From the data accumulated in this little exercise, it looks like adding the equivalent of two starters (or 9% of all snaps) to the roster is a good target for the first year of a rookie class. After that, you'd probably want to come out with the equivalent of three starters (13.6% of all snaps), and everything above that is just gravy.
The Cowboys have not hit those marks all that often, which is one reason the team saw fit to bring in so many new players via free agency earlier this year. If you hit on three starters in every draft, you'll be on a roughly seven-year cycle of roster renewal, and wouldn't need to bring in all that many free agents. When you only hit on two starters, that cycle extends to eleven years, which is much longer than the average span of an NFL starter's career, and you'll end up having to plug holes with free agents.