Follow Up on QB Fragility
After reading the reactions to the first diary I wrote on the issue of QB injury rates, I thought it’d be worthwhile to go back and address some of the skepticism still lingering. For the most part, the source of the skepticism was in regards to the number and scope of the data points or in how the QBs were split into their Threat Level categories.
More Data Please
Addressing the first issue was straightforward—get more data. I included the 2004-2007 seasons for a total of 5 seasons including 2008. The scope was all FBS schools and all starting QBs with starters defined as players who averaged more than 17 plays (passes + runs) per game they played in. This level of play was chosen based on the median of the data in that category. One tweak I added was to increase the resolution of the data to include partial games (ie. if a QB gets knocked out in the 3rd quarter and missed the next two games, I counted 2.25 games against him). I also corrected a few errors I found along the way.
Cherry Picking
The issue of the chosen break points was simply a matter of choosing one arbitrary line in the sand over another, I went with the one I thought made the most football sense. I actually considered using the quartiles of the data as break points to ensure that there would be equal numbers of QBs in each category. But, we know that this simply isn’t the case—there are way more Jimmy Clausen/Mark Sanchez/Matt Staffords (Threat Level 0) than there are Pat White/Terrell Pryor/Tim Tebows (Threat Level 3).
The goal of using categories was to group similar players together in an unbiased way. Using whole number denominators (1 run per 2 passes, 3 passes, etc) was a reasonable football-sense based method to do this. Using quartiles would have put the level 3 split data at 2.78 passes per run…huh? Ok so maybe you round up to three then but a) how is that not arbitrary and b) does it make sense to put Steven Threet into the same category as White/Pryor/Tebow? Obviously not…
Regardless of all that, the expanded dataset neutralizes this concern
The Goods
Anyway after all the grunt work was done, not much changed but the extra data does yield more insight. The average injury rate for all QBs was 23.6%. Level 3 running threats came in at a 25.3% rate and level 0 threats were injured at a 23.9 % clip. I’ve left my hypothesis testing skills mercifully nestled amongst the dust and cobwebs of my mind but there’s no statistically significant difference here. The theory that option QBs are more likely to get injured than the average QB is a load of crap.
There does seem to be a significant deviation from the norm in the injury rates of level 1 and level 2 QBs, with 1’s getting injured at a lower than average rate and 2’s getting injured at an above average rate. A possible explanation for this is that Threat level 1 QBs enjoy the safety of the pocket but also have the ability to escape from pressure and not be sitting ducks like threat level 0 QBs. On the other end of the injury spectrum, level 2 QBs leave the pocket but don’t have the speed/agility/field vision/down field linemen necessary to elude defender’s looking to teach them a lesson. This is definitely an eye opener. If you’re going to ask your guy to be a running threat on a regular basis, he had better be a slippery one and you’d better have blockers on the second level. Check and check.
The last interesting note is that 1 out 4 teams can expect to lose a QB for about 3 games; that’s 3 teams each from the B10, SEC, ACC, etc. I would have never guessed that. Another way to look at it is that a recruit can/should be expected to miss 3 games over a 4-year college career.... yikes. Having at least 2 game ready backups is an absolute must, regardless of offensive system.
Threat Level |
No. of QBs |
Injured QBs |
Lost GMs |
Avg. Games Lost |
QB Inj % |
2008 | |||||
3 |
26 |
6 |
7.5% |
3.08 |
23.1% |
2 |
24 |
10 |
7.7% |
2.33 |
41.7% |
1 |
46 |
11 |
9.2% |
4.89 |
23.9% |
0 |
64 |
14 |
4.8% |
2.79 |
21.9% |
2007 | |||||
3 |
19 |
7 |
7.3% |
2.5 |
36.8% |
2 |
26 |
7 |
5.5% |
2.57 |
26.9% |
1 |
35 |
7 |
6.5% |
4.04 |
20.0% |
0 |
79 |
19 |
6.9% |
3.61 |
24.1% |
2006 | |||||
3 |
14 |
4 |
7.4% |
3.19 |
28.6% |
2 |
34 |
13 |
10.4% |
3.38 |
38.2% |
1 |
36 |
4 |
4.6% |
5.31 |
11.1% |
0 |
60 |
13 |
5.1% |
2.96 |
21.7% |
2005 | |||||
3 |
19 |
4 |
5.5% |
3.00 |
21.1% |
2 |
29 |
8 |
8.5% |
3.47 |
27.6% |
1 |
36 |
6 |
3.0% |
2.08 |
16.7% |
0 |
60 |
16 |
6.2% |
2.72 |
26.7% |
2004 | |||||
3 |
17 |
3 |
3.6% |
2.33 |
17.6% |
2 |
28 |
4 |
1.6% |
1.25 |
14.3% |
1 |
40 |
6 |
3.5% |
2.67 |
15.0% |
0 |
63 |
16 |
7.4% |
3.39 |
25.4% |
All Seasons | |||||
3 |
95 |
24 |
6.3% |
2.81 |
25.3% |
2 |
141 |
42 |
6.9% |
2.81 |
29.8% |
1 |
193 |
34 |
5.6% |
3.88 |
17.6% |
0 |
326 |
78 |
6.1% |
3.13 |
23.9% |
All |
755 |
178 |
6.1% |
3.3 |
23.6% |
Brace for Impact
Given the rhetorical skill of most of the visitors of this site, I’ll take a second to put out a preemptive strike against the “how do we know Tate/Denard/Devon wont be a level 2 Threat?” argument. Simply put, we don’t. But, the categories aren’t an explicit evaluation of the athleticism of the player; they only allow us to infer his physical skills by how he’s deployed by the coaching staff.
Example. Juice Williams ended up as a marginal level 2 QB in 2008 with an R/P ratio of 0.46. The previous 2 seasons he qualified for level 3 status which is not a surprise. His skills didn’t diminish and the offensive scheme of the Illini did not change but for whatever reason, he ran a few time less than before and ended up in the upper end of the same category as Steven Threet. Actually, he ran more often (+2 runs per game ’07 v. ‘08) but passed a lot more (+11 passes per game).
Now on the flipside, does anyone believe that Threet would have had a better chance of staying healthy if we had run him more? The point is that the athleticism of the QB determines his injury risk outside of the pocket, not the number of excursions outside of the pocket he makes.
August 6th, 2009 at 11:23 PM ^
August 6th, 2009 at 11:29 PM ^
August 6th, 2009 at 11:30 PM ^
August 7th, 2009 at 10:22 AM ^
August 7th, 2009 at 10:51 AM ^
August 7th, 2009 at 11:00 AM ^
August 7th, 2009 at 10:09 AM ^
August 7th, 2009 at 11:28 AM ^
August 7th, 2009 at 11:38 AM ^
August 7th, 2009 at 12:35 PM ^
August 19th, 2009 at 4:54 PM ^
August 22nd, 2009 at 1:37 AM ^
August 22nd, 2009 at 11:29 PM ^
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