USC 2010 Defensive Comparative Stats

Now that the 2010 season is done for USC, this gives me some time to take a more in-depth look at the stats involved with USC.  Like the last post, this post will be looking into comparative stats.  This post will deal with the defensive side of the ball.  First I will explain what a comparative stat is and the significance of them, then we will go over a few key comparative stats: total defense, passing defense, rushing defense, 3rd down conversion defense, and scoring defense.

What are Comparative Stats?

Comparative Stats look at a team’s production compared to what the opponent allows on average.  For instance, if a mythical opponent were to gain 500 yards of offense against USC’s defense, one might think “wow, USC’s defense is really bad.”  However, if this mythical opponent gains 600 yards of total offense on average throughout a season, then suddenly the tune changes.  In this situation, USC has held the opponent to 100 fewer yards than what the opponent typically gained, which shows a stronger USC defensive performance.

By using this over a number of games, you can see various trends on how good or bad a team is in a particular area.  A strong defense will consistently force their opponents to gain less yards than the opponents’ generally gain in various categories.  On the flip side, a poor offense will allow higher than average for comparative stats.

Please note that this is only part of the overall picture of football.  Losing in comparative stats in a particular game can be completely negated by forcing turnovers, etc.  Using comparative stats is just one tool we can use to try to see how good a portion of a team is.

So with that in mind, let us look at some comparative stats for USC’s defense.

Total Defense

Lets take a look at how USC’s total defense compares to what their opponents’ typically gain.  Here is a chart which shows how many total offensive yards USC allowed against each opponent (shown in Cardinal) vs what that team’s offense is credited for on their average total yards for the year (shown in Gold).  Remember, a lower number is better for defense.  This means a negative margin is desirable.

There were three games in which USC’s defense was torched for more than the opponent typically averages.  Hawaii gained 91 yards more than they typically gain.  Oregon gained 62 yards more than their already high average of 538 yards per game of total offense.  Finally, Washington really outperformed the USC defense by gaining a whopping 172 yards more than they average.  Also of note is that UCLA gained 41 yards more than they average.  On the flip side, there were a few good games by the USC defense as well.  Arizona was held 41 yards below their average and Minnesota was held 54 yards below their average.  Virginia was also held to 65 yards below their average offensive output.  Both California and Notre Dame were held just over 80 yards below their average.  Now let us look at the trend chart for USC’s total defense.

As can be seen, there is a general downward trend for the USC defensive comparative margin.  Remember that a negative trend is good in terms of defense.  There are still a number of high spikes, including the final game at UCLA.  However, as the season progressed, these spikes were lower in magnitude while the low points in the margins stayed relatively consistent.  On average, USC’s defense allowed 0.87 more yards than their opponents typically gained.  In terms of total defense, USC was very middle of the road.

Passing Defense

Now let us look at the passing defense and how the very inexperienced secondary performed.

USC’s passing defense was very inconsistent, which is somewhat to be expected due to the secondary’s inexperience.  There are five games of note in which USC’s secondary performed poorly.  Arizona was able to throw for 43 more yards than they averaged over the season.  Oregon gained 54 yards more than they averaged.  Hawaii gained 71 yards more passing yards than they typically gained, most of those probably yards after catch due to poor tackling in that game.  UCLA gained 88 yards more than they averaged.  And finally, Washington gained a whopping 111 more yards than they typically averaged.  On the flip side, there were three games in which USC’s secondary outperformed their opponents.  Against Oregon State, the secondary held the Beavers 53 yards below their passing average.  Virginia was held 76 yards below their passing average and Notre Dame was held 108 yards below their average.  However, USC still lost in two of the three games the secondary performed well.  Time to look at the passing defense’s comparative margin trend.

There is an overall downward trend for the secondary, which again is a good thing.  This trend is aided by strong defensive performances against Oregon State and Notre Dame.  However, the vast majority of games had the opponent either at their average or gaining more yards through the air than typical.  On average, the USC secondary allowed 14 more yards through the air than the opponents typically gained.

Rushing Defense

Now let us look at the rushing defense.

Once again, the USC defense had a very inconsistent rushing defense.  However, the front seven did a much better job than the secondary.  There were two games in which the defense allowed a significant amount of rushing yards more than the opponent averaged.  Oregon State gained 54 more rushing yards than they averaged and Washington gained 61 yards more than they averaged.  Both these games ended in losses.  On the flip side, there were four games in which USC’s defense did well against stopping the run.  UCLA’s run-first pistol offense was held 48 yards below their average rushing.  Minnesota was also held 52 yards below their rushing average.  Arizona was held 84 yards below their average and California was held a strong 107 yards below their average.  All those four games were victories.  Now let us look at the trend chart for the rushing defense.

The rushing defense was very inconsistent, which can be seen in the graph.  There are only a handful of games which fall near the trendline “average” for the team.  Most of the games erratically bounced up and down beyond the trendline.  However, there is a general downward trend which shows improvement for the defense over the season.  Overall, the defense held opponents to 14 yards below their average rushing attack.

3rd Down Defense

3rd down conversions allowed is a bit of a sore spot for USC.  The conversions fans remember most were the 3rd and longs which were allowed to convert.  But let us take a closer look at the 3rd down defense for USC.

There were five games in which USC’s defense did poorly against their opponents.  Washington State converted 9% more 3rd downs than their average.  Hawaii, Stanford, and Oregon were all allowed to convert about 15% more 3rd downs than they typically averaged.  Arizona was allowed a whopping 69% conversion rate on 3rd downs, which is 32% more than they typically convert.  On the flip side, there were five games in which USC held their opponents under their typical 3rd down conversion rate.  Washington and Oregon State were held just below 10% under their average.  Virginia converted 11% below their average 3rd down conversion rate.  Cal converted 15% under their average and ASU converted 18% under their average.  Time to look at the trend chart for 3rd down conversions allowed.

Again, there is a general downward trend.  However, the games which the defense allowed more conversions than the opponents typically gained had a higher positive margin than the games with a negative margin.  Overall, the defense allowed 2% more 3rd down conversions than the opposing offense typically allowed.

Scoring Defense

Now to look at the scoring defense for USC.

There were only two games which USC’s defense allowed a significant number of points more than the opponents typically scored.  Washington scored 10 points more than they typically scored and Oregon State scored 12 points more than they averaged.  Both these games ended in losses (with the Washington loss coming as a single point loss).  On the flip side, there were three games in which USC held the opponent to a significant amount of points below their average.  Arizona was held nine points below their average.  Both Virginia and Cal were held about 11 points below their average.  It is also worth noting that Notre Dame and UCLA were both held about six points below their averages.  Now let us look at the scoring defense trend.

This is the only defensive category which had an upwards trend.  However, even with the upwards trend, the USC defense had a number of games which held opponents under their averages.  The two large peaks against Washington and Oregon State really hurt USC’s scoring defense.  Overall, USC still held opponents an average of 2.4 points below their typical scoring offense.


As with the offense, there is a mixed bag here with the defense.  On one hand, there is a general downward trend throughout the season in defensive comparative margins.  This shows improvement from the defensive unit.  However, there USC’s defense is still holding opponents to their averages or even allowing more than their average in too many categories.  This shows a very average USC defense.  There is also the upwards trend in the scoring defense which may be a concern as well.  The key question is how the defense will move going forwards.  Will the improvement continue into next year to make this defense above average?


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