USC Trojan fans have fretted extensively the past two seasons as the team's offensive production has marginally declined. In hindsight this decline was somewhat inevitable after the 2005 season when the strongest offense in USC history largely departed for the NFL.
Still however the most recent Trojan squads did not match up to the level achieved by the 2002 to 2004 teams fielded by Head Coach Pete Carroll.
Whenever offensive points production falls off the normal fan and media tendency is to put all the blame on either the quarterback and/or the offensive coordinator. While this is indeed often the case there normally is more to the picture than initially meets the eye.
This article takes a closer look at USC football points production using five different categories across several years. The intent of the article is to analyze the points scored by the Trojans as well to identify the main sources of variation.
I did not fully include 2001 or 2002 in this study since the scoring drive charts were not all posted online by USC's Athletics Department for those games. For the few games I sampled however the same trend that I will explain below held true.
For starters lets review USC's total points production over the past seven years.
| Year |
2001 |
2002 |
2003 |
2004 |
2005 |
2006 |
2007 |
'01-'07 Average |
| Points Per Game |
26.55 |
35.77 |
41.08 |
38.15 |
49.08 |
30.46 |
32.62 |
36.24 |
A more detailed look on a game-by-game basis is contained in this next graphic below as well. The following trend chart below includes the game-by-game average, a linear trend fit, and a sixth order polynomial trend fit as well for the entire period.
The lowest year in terms of points scored during the Pete Carroll era for USC is 2001 at 26.55 points per game in his first overall season at the helm. The highest level is of course the 2005 Trojan edition at 49.08 points per game when Matt Leinart, Reggie Bush, LenDale White, Steve Smith, Dwayne Jarrett, and others lined up on offense.
The average points per game scored for USC over the seven year span is an impressive 36.24 points per game. The past two years however have been on the lower side of this figure.
(Note: Keep in mind that the 2006 season in college football was effectively 10% shorter due to changes in the game clock rules that year. I will not adjust for that effect but any cross year comparison should probably bump those figures up by roughly that amount.)
A big problem however with looking at the scoring data at this aggregate level is that the total combines so many different factors it is hard to sort out with respect potential sources of the variation. For example in football:
- The defense scores points at times on safeties, interceptions or fumbles recovered and returned for scores
- Special team units can score points on punt and kick off returns for touchdowns or blocked kicks
- Teams typically score on offense at a higher percentage after turnovers by the defense
- Teams can score on short field (SF) scores (less that half the field) after blocked kicks, or turnovers, or excellent kick returns
- Teams can score starting from normal medium field (MF) position starting around the 30 yard line
- Teams can score on long field (LF) drives of 85 to 90 yards or more
Each of these categories is indicative of a different relative strength or weakness in a given year. The first four categories for example are reflective of how defense and special teams play directly and indirectly contribute to scoring by the offense.
The latter two cases are more reflective of the true offensive capability in my opinion since those involve sustaining drives the length of the field. It is worth looking at each of these closer in detail for greater insight into how a team actually scores. For simplicity I chose to break things into the five categories listed below.
Category 1 = Defense or Special Teams Scoring.
Category 2 = Scores on offense after a turnover (TO) caused by the defense.
Category 3 = Other scores (Non turnover related) or short field (SF) drives starting on the opponents 1 to 50 yard line.
Category 4 = Medium field (MF) drives for TD by the offense without the benefit of turnovers and starting between the USC 21 and 49 yard line.
Category 5 = Long field (LF) drives for TD by the offense without the benefit of a turnover and starting between the USC 1 to 20 yard line.
Here is the five year summary in terms of a) scoring drives and then b) points:
| Category | Scoring Explanation |
2003 | 2004 | 2005 | 2006 | 2007 |
| 1 | Defense or Special Teams |
11 | 3 | 4 | 3 | 0 |
| 2 | Scores off TO's | 18 | 22 | 22 | 12 | 18 |
| 3 | Non TO SF drive (1-50) | 12 | 9 | 10 | 4 | 9 |
| 4 | Non TO MF drive (49-21) | 26 | 37 | 28 | 32 | 28 |
| 5 | Non TO LF drive (20-1) | 22 | 9 | 34 | 15 | 15 |
| Sum Total | 89 | 80 | 98 | 66 | 70 |
Converting the scoring data into more the familiar points look results in the following numbers:
| Category | Scoring Explanation |
2003 | 2004 | 2005 | 2006 | 2007 |
| 1 | Defense or Special Teams |
5.1 | 1.6 | 2.1 | 1.7 | 0.0 |
| 2 | Scores off TO's | 8.1 | 10.0 | 11.2 | 5.8 | 8.1 |
| 3 | Non TO SF drive (1-50) | 5.2 | 4.2 | 4.7 | 1.8 | 4.5 |
| 4 | Non TO MF drive (49-21) | 11.8 | 17.8 | 14.1 | 13.5 | 12.9 |
| 5 | Non TO LF drive (20-1) | 10.9 | 4.5 | 17.0 | 7.7 | 7.1 |
| Total | 41.1 | 38.1 | 49.1 | 30.5 | 32.6 |
As you can see the sub-totals move around a bit and are pretty interesting once you start comparing the sections with each other across time. I will put them into bar chart format for easier viewing and explanation purposes. Let's start with Category 1—direct scoring by either the defense or special teams.
These initial numbers are not large but they are still significant. The 2003 edition of USC football for example was amazing in that the defense and special teams scored almost a dozen times in one season without the offense ever taking the field.
There were two safeties as well as five interceptions returned for TD (Will Poole, Lofa Tatupu, Jason Leach, Ronald Nunn, and Omar Nazel one each). In addition there were four fumbles returned for touchdown (two by Mike Patterson, and one each by Ronald Nunn, and Kenechi Udeze).
That amount alone accounts for 67 points of the USC total scoring offense that season or an impressive 5.1 points per game on average. Each squad afterwards has scored fewer points in this manner and the 2007 edition was the first team of the Pete Carroll era to be shut out on defense or special teams in terms of scoring.
Even in 2006 LB Brian Cushing scored once versus Notre Dame on an on-side kick off return and CB Terrell Thomas scored once versus Stanford on a blocked kick for example.
Of course direct scoring by the defense and special teams is one thing but contribution of good field position and positive momentum is another to be considered.
In the Rose Bowl game ABC put up the following picture in the game in the fourth quarter reflecting points production after turnovers in the 2008 Rose Bowl game.
Sudden "momentum shifts" after turnovers are forced by the defense clearly benefit the offense and subsequently affect how teams score for a couple of reasons. Of course there is the psychological advantage to the offense in these cases.
In addition, however, is the simple gain in terms of relative field position. The average spot over the past few years after the USC defense forces a turnover is roughly the opponent's 40-yard line.
After a turnover the offense starts with a "short field" advantage and only has to move about 10 yards to get into field goal range and 40 yards to score a touchdown.
USC is about 70% likely to score from such a spot the last time I checked. Combining the points in the first rows from above (direct scores by defense and special teams) along with points scored after a turnover the past five years you get the following result for categories one and two.
As you can see that is a pretty interesting insight. A very significant amount of USC scoring in any given season is a product of either direct scores by the defense or special teams, beneficial short field position, or the momentum created after turnovers by the defense.
This result becomes important when you also consider the trend the past several seasons for USC football in terms of net turnover margin (see below).
For this turnover trend data I'll go back to 2002 since the information is easily obtainable.
The blue columns indicate the turnovers forced on defense by either fumbles or interceptions. The middle bar is the number of turnovers committed by USC on offense. The third and lightest colored bar is the differential for the year (i.e. turn over margin).
Quite disturbingly turnovers forced by USC have fallen the past two years while turnovers by the offense spiked in 2007.
For USC the turnover differential has been extremely small now for two consecutive seasons. That may sound insignificant but remember that the average field position after a turnover is the opponents 40-yard line for USC.
From 2002 to 2005 that meant 38 to 42 drives per year that started *on average* inside the opponents half of the field. From there USC is highly likely to score roughly 70% of the time by my calculations.
When there is no turnover forced by the defense USC or any team instead gets the ball back via punt for example and loses 40 or so yards of field position and starts around or inside its 20 yard line.
Conversely when USC commits a turnover it in turn gives the opponent a shorter field to work with as well. That net effect is large and troubling when I look further at the data.
Of course even where there is not a turnover USC often gets a nice kick off return, punt return or the occasional shanked punt, etc. to help field position.
Those instances all can provide USC with short field position in a variety of subtle ways. I calculated those effects separately as Category 3 instances from the table above. Adding up rows one through three above now provides a complete total of all short scores (i.e. less than 50 yard drives), as well as points after turnovers, and points directly scored by the defense.
The trend now starts to become somewhat alarming when these three components are added together. As you can see below the USC offense the past two years clearly has not benefited from short field scoring opportunities as much as it has in previous years.
(Note: I sampled four games for 2002 and it was roughly the same picture.)
Next here is what is left over when you strip away the first three categories and see what the offense can do when it starts on its own side of the field and has to travel at least 50 yards to score and does not have the sudden momentum change advantage stemming from a turnover.
The following chart reflects Categories 4 and 5 put together and shows what the Trojan offense has done in terms of points production when starting on its own side of the field.
In my opinion this is the most accurate measurement solely of offensive points capability since it nets out most of the help often provided by special teams or defense. The result is surprising flat across four of the years and of course still spikes upward for the amazing 2005 USC offense.
The 2006 figure might be bumped up a small amount as I mentioned above due to the scoring clock rules for that season.
If you look at the breakdown in terms of points scored by USC as organized above the following conclusion pops out that I mentioned above.
The biggest problem the USC offense has had the past two years in terms of scoring has mainly been a decline in short field scoring opportunities which in reality are created as much or more by defense, special teams, and other events.
That message might seems somewhat perplexing at first but here are some additional points to keep in mind that tend to back it up overall.
For starters third down and fourth down conversion percentages have been improving overall the past seven years for USC on offense. The 2005 squad was of course the highest but the next two best seasons have been 2006 and 2007 by a slight margin. Fourth down conversion exhibits a somewhat similar trend.
Next here is a look at the average drive length by USC the past few seasons. This figure is calculated by taking all the yards for a given season and dividing it by the total number of drives for the year.
I did not sort the data and pick out the one play kneel downs etc. before halftime or the end of the game. So this amount probably understates the "real" number by a slight margin and may affect a couple years more than others but the effect should be small (i.e. a yard or two at most).
Average yards per play over the seven year provides another insight that I think is also very revealing in terms of the total picture. USC was indeed better on offense in the years of 2003 to 2004 by about a half yard per play and of course by a larger amount in 2005 than the past two seasons.
Those years correspond directly with the development of Reggie Bush, Matt Leinart, LenDale White, the wide receiving corps and one of the best offensive lines in recent USC history. The years of 2002, 2006, and 2007 in comparison have indeed been more "ordinary" compared to those years.
In conclusion let's return to the total points situation for the USC Trojans. If fans want to see an increase in points scored per game there are of course multiple ways for the Trojans to accomplish this goal.
- For one the defense and special teams could come though again and score more some points directly. However I am not optimistic about this possibility given the past two years. 2003 in reality was probably quite unique in that regard for USC.
- Alternatively the defense also can contribute in a major way by producing the same level of turnovers accomplished in years 2001 to 2005. That would dramatically help field position and increase the probability of any given scoring drive for USC on offense (e.g. more short field opportunities).
- The more conventional angle of course is for the offense to become more explosive in terms of big play potential and increase the number of long field drives that result in scoring.
With skilled players such as Joe McKnight and Stafon Johnson at RB and many other talented receivers returning the third option indeed may be possible in 2008 for the Trojans.
However, the unknown variables at this point in time for USC on offense are of course 1) the QB position with new starter Mark Sanchez at the helm, two) the depth and talent of the 80% new offensive line, and of course three) the inevitable injuries and position shifts that will occur, etc.
With no up tick in turnovers and short field opportunities however I suspect USC will remain "stuck" around the level of 32 points per game on offense. That level is nothing to sneeze at but it feels slightly low compared to the past several seasons (a sign of how spoiled USC fans have already become?).
Keep in mind however that improving the offense is not the only thing required to win a national championship for USC or any other team for that matter.
The Florida Gators for example won the national title with a 13 Wins and one Loss mark in 2006 compiling 396 yards per game (19th in the country) and 29.7 points per game (23rd overall in scoring). That team finished strong however and had a suffocating defense at the end of the year.
In 2007 the Florida Gators improved both offensive marks to 457 yards per game to rank 14th in the country and averaged 42.4 points per game to rank third in scoring.
Despite these improvements however the Gators only finished the year with nine Wins and four Losses. Winning in football still consists of offense, defense, special teams, coaching, player talent, and other intangibles that can't always be quantified.
I'll check this trend again for USC to see how things differ in another 12 months at the end of 2008.
Other overall trends for USC and the Pac-10 are available here for those interested www.trojanfootballanalysis.com
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4 months ago
Great analysis. The short answer is that (according to the data you provided), 60% of the decline in scoring from 2005 to 2007 was due to the long field, non-turnover category. Another 32% comes from combined scores off turnovers and defense/special teams. This 32% is well documented as USC has declined conistently it their ability to force turnovers. However, the 60% from long drives is suprising and shocking, and points to a much larger issue with the offense.
Keep up the good work!
from 4 months ago
Thanks Bill. Not sure which way you are coming up with the 60% figure that you mention? LF point trend is pretty flat and down by 10% or so when looked at on a year to year basis (e.g. 22-23 points in 2003-4 versus 21-20 points in 2006-2007). Categories 1-3 short field points which are a combination of things are down the most in comparing years (15-18 points in 2003-2004 versus only 9-12 points in 2006-2007). That is most of the delta when looked at on a year to year basis by category. I suspect you are measuring something else...it always comes down to what are you measuring, what baseline, and over what period, etc.
I was surprised though to see the overall improvement in 3rd and 4th down conversion % though and the big drop off in turnovers. I did not post something more detailed. It is a more true look at scoring conversion probability by field position. There has been a big decline in both short field scores and short field opportunities. I sent this to HC Pete Carroll via an intermediary. He was kind enough to respond and agreed that the TO drop off was a major concern for him and its affects on scoring were noticeable. Also he points out that there has been a drop off in "big plays" either +12 runs or +16 yard passes as well. That comes back to the players and the offense etc. JD Booty, CJ Gable, and Patrick Turner, etc. have not quite lived up to their predecessors yet. I hope to cover that drop off in another post soon.
Thanks again.
Art
4 months ago
Wow... incredibly in depth. I'll have to go back and re-read some segments just to make sure I got it all. I'm glad you noted the game-shortening in 2006. That's important as there are some new rules in place this year that might have a similar effect.
Still, there aren't many BCS teams who can be uneasy about being "stuck" on 32 points per.
Great article, hope we can hear more from you this season.
4 months ago
The answer to the scoring decline is very simple and you don't need any graphs for it...
it is ALL about the OFFENSIVE COORDINATOR -
NORM CHOW was AWESOME,, after he left,,
the others trying to fill his shoes have been the OPPOSITE of awesome.
Hopefully, they pull their heads out of their arses, go to Norm Chow's clinics , and
improve a little bit.
It was very CLEAR that our 'o' coordinators have been getting their heads handed to them by their counterparts... it has been like watching a 10 year old at the wheel of a Ferarri.
The 'o' coordinator gameplanning and play-calling need to DRASTICALLY improve.
from 4 months ago
The nice thing (to me at least) is that Norm Chow will be back in LA coaching for UCLA. That will be entertaining to watch. If you read the Titans Chat boards they absolutely ridiculed him in the NFL for his offense and inept play calling. It was sad to read to say the least...I have attended conferences where Norm presented at USC. I also have his book on the passing game, his old playbooks, and overhead coaching film, etc.
The year that Norm Chow was most in charge of the USC offense was 2001. After that it was modified by Pete Carroll. It was commented upon by Loel Schrader and Steve Bischeff in their book about USC football available on Amazon. Here is a passage from the book:
According to the authors:
Although there was little talk by the staff about a change in offensive strategy after the 2001 Las Vegas Bowl loss (USC lost 10-6 to Utah to finish the season with 6 wins and 6 losses), Carroll told the authors of this book the Trojans were "so awful, disgraceful," that he "decided that we were going to change the offense."
A former member of the staff said Carroll, in effect, "junked the BYU offense" Norm Chow brought with him to USC in 2001. Carroll turned to two professional coaches for assistance -- Alex Gibbs of the Denver Broncos and Jon Gruden, who was then at Oakland but moved to Tampa Bay. Denver had been known for possessing the best running attack in the NFL, and Gibbs was generally accorded most of the credit for developing it. Gruden was young, but he was known for his passing schemes and offensive brilliance. Each summer, Lane Kiffin has spent time with Gruden, who is head coach of the Tampa Bay Buccaneers. His defensive coordinator is Monte Kiffin, Lane's father.
"I had decided we were going to do the whole offense over again," says Carroll. "I had gotten real frustrated with our offense, and I always wanted to be more involved to see if the things and concepts I liked would work. But I always gave in to the coordinators I had. This time, I decided this might be my last shot at being a head coach, and I'm not going to go down that way. I'm not going to leave it all on somebody else's shoulders. So, I spent the off-season working with the offense, and we recreated everything--philosophy-wise, rhythm, and principles--and the results have been phenomenal. The first game against Auburn, Carson Palmer was poppin' that ball around, and we were running the ball better. I even told the guys, 'I don't care if we're the best running team in the conference, just get it to average.' That was how high I set my goals then."
When Chow was praised for what "his" offense was doing, the offensive coordinator would make a point of saying, "It isn't *my* offense, it's Pete Carroll's offense." But most USC followers assumed Chow was just being modest, when, in fact, he was telling it like it was. (End of passage)
I'll be charting Norm's progress at UCLA the next couple of seasons. It should be great for a few articles.
from 4 months ago
Wow, Arthur! Great stuff in your article, but even better job following up the response about the offensive coordinator. I full-heartedly believed that Steve Sarkisian was inferior to Norm Chow, and your reference from the book kind of opened up my eyes--although I'm still have some doubt until we see how the offense pans out with Sanchez at the helm--albeit I am super optimistic about our chances with Mark to get back the offensive prowess we once grasped. The scariest part, Arthur, is that even due to our offensive decline in the past two years under John-David, we still had chances to get into the BCS national championships the past two years (only to be beaten in a *rivalry* game in 2006 and unfairly left out to contend in 2007).
4 months ago
Art,
Excellent, in-depth post as are all of your posts at WeAreSc. I had one question. Any data on the length of kick-off and punt returns averaged over the last two years? It seems to me that there would have been a fall off from the Bush era, especially back in 2006. It probably ticked up a notch or two in 2007 with RoJo and McKnight.
I'm glad you're posting on B/R now as well for all of our fans and writers here. Looking forward to more great stuff during the season.
4 months ago
Yeah,
that Chow guy was incredible. Incredibly calling 3 straight runs into the middle of the Cal line for Dennis when Dennis went down if a leaf fell on him. I agree. He was a flawless playcaller.
Get real! I liked Chow as well, but nobody is God. I think there are many factors to consider but in looking at the small turnover margin and the lack of scoring from defense/special teams; that's what stands out; however...
...don't forget that in regards to the stats, stats don't tell the whole story. When Booty went down with an injury, PC played it much more conservatively in regards to the offense. And, in the first 6-8 games of Booty's 1st season he also played it close to the vest.
All of those games will skew the stats; that's why stats are fun, but rather meaningless in the final event.
4 months ago
Wow, this is by far one of the best analytical articles I've read here on B/R - and I'm not just saying that because it's about my favorite team and alma mater. Great in-depth analysis, and a joy to read. I'd have to say that in addition to the added big play potential from McKnight and Stafon to increase the number of long scoring drives, there is a likelihood of more defensive turnovers this year with the depth and experience of the linebacking core, the maturation of Taylor Mays, and the emergence of some beastly new pass rushers along the D-line. I'd expect turnovers to increase this year, and it is up to Sanchez and the O to capitalize on them more. Thanks again Arthur and I look forward to your future contributions here.
4 months ago
This gets my POTD! I have always maintained that one of the biggest reasons why USC hasn't been as good as a few years ago is due to turnover margin. Your graphs validate that. Outstanding read! Five stars!
4 months ago
This a great article. When statistical analysis is applied to sports, it's usually only in the context of baseball. It's nice that this article applies the same methods to college football, and the link at the bottom is excellent as well. (in a word: POTD).
4 months ago
Arthur,
Here's the way I came up with 60%. First of all, I was just looking at 2007 (most recent year) compared to 2005 (peak year). Overall scoring dropped 16.5 ppg. Non-TO LF Drive scoring dropped 9.9 ppg. 9.9 is 60% of 16.5. In other words, a real high-level (dumbed-down) view says that 60% of the scoring decline from 2005 to 2007 was in Non-Turnover long-field drives.
I sometimes get accused of making things too complicated. Hopefully my 2nd attempt was better!
from 4 months ago
Thanks Bill. I figured it had to be something like that. You essentially made a peak to bottom comparison comparing two years (2005 and 2007) if I understand now. I was making a broader point across the entire series. I figured we were using different comparison points somehow. That is usually the case in this sort of thing.
The other way to look at is using averages across the set of data points. The average for example is 36.24 points overall across the series. A low year (I'll exclude the terrible 2001 season) such as 2006 scored 30.46 points which leaves a gap of just under 6 points per game. On average that difference is *roughly* about 1/3rd LF points and 2/3 SF points. I am leaving out the unfortunate problem that the game was also about 10% shorter that season as well.
Either way though USC has a "gap" on scoring and they need to close it or fans will not be happy I guess. I'll have a follow up post in a few days that also shows the decline in the big play category that Coach Carroll mentioned. Thanks again. Art
4 months ago
this is a new year, a NEW trojan O .I do beleive that we will be quite impressed on how sark , sanchez and crew lead a young but very talented trojan team to many victories this season.(12-0) Oh, and dont forget rey-rey,cushing,mays and the extremley fast and physical "D" AS THEY SHUT DOWN every one this season!!!!! FIGHT ON.. FIGHT ON!! RTSTROJAN ,REPRESENTING ALL THE WAY FROM HARRISON ,ARKANSAS.
4 months ago
Excellent Art, thank you.
One small point: there is something of a self-correcting, closed-loop system when looking at percentage completion of fourth downs. Although I can't prove it statistically, it sure seemed to me last year that with a less explosive and reliable offense, the Trojans were more conservative on fourth down attempts, thus possibly impacting their relative success on fourth downs. When doing this article with 2008 data, it might be interesting to look at the raw numbers of attempts as well as percentage completion. Or, perhaps look at the length of fourth down plays. In 2005, it sure seemed that if the Trojans were on their half of the field, they'd go for it on fourth down.
4 months ago
Wow, excellent work man. Could this of possibly been someone's end of the year stat project?
3 months ago
The quoted portion of the book is pure Pete Carroll self-agrandizing. His ego constantly overwhelms the truth. Count how many time he says "I" in those paragraphs. Really, no one else was even there with a suggestion?
Chow is the master of "elegant play calling." He had different personel after the first year so, of course, things were changed to take advantage of that. In at least one practice where I was present, Chow drove Carroll to the point of red-faced screaming because the defense was getting beaten.
Give Carroll credit for recruiting but not play calling on offense.
For the truth get in touch with Carson Palmer or Matt Leinart.
from 3 months ago
Chow was very good for the QB's. He coached receivers for years at BYU and it could be inferred that he learned Quarterbacking there from the likes of Mike Holmgren. Carroll may not have been too involved in the offensive X's and O's, but getting Chow to work with Gruden and Gibbs, not to mention bringing in Wisconsin's Tim Davis, only complemented Chow's passing game knowledge and coahing ability, which in my opinion are exceptional. Too bad he had to work with Vince Young in the NFL.
I'm a BYU fan for years, and recognize that Chow could pass the ball on anybody, but could never put together a sophisticated running game. And let's face it, the big years of USC were largely power running and Norm's ability to match up receivers well against a defense and coaching the QBs & WRs how to exploit things.
That said, I have been worried about the USC offense, particularly since Tim Davis left. The 2007 Rose Bowl was two identical zone running offenses that nearly produced the exact same results had not Pete had Michigan's number since the 2004 Rose Bowl. USC has too much size and power to be a strictly zone team. Zone blocking and spread offenses are meant for leveling the playing field for smaller teams, something USC does not need to try to do (see Michigan v. Appalachian St.).
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