A Look at Penalties

It has been about six weeks since my last post, which was after the Stanford game.  In those six weeks, I have been very busy at work doing long hours and weekends, including working on gamedays occasionally.  Well, the work schedule has finally slowed back down to the normal pace, just in time for me to write another post following a USC loss.  Bummer.

This post will take a look at USC’s penalties this season.  We will first look at an overview of penalties for USC this season.  Then we will look at how penalties have affected offensive drives and USC’s ability to convert first downs.


After eight games, USC ranks dead last in both penalties per game (10.25) and penalty yards per game (84.63).  USC gets 1.69 more penalties per game than the second-to-last team (FIU) and gets 4.75 more penalty yards per game than second-to-last team (UCLA), so it isn’t even really close (from second-to-last to third-to-last, the margin is 0.06 penalties per game and 2.0 penalty yards per game respectively).  Against Arizona, USC was penalized 13 times for 117 yards.

Let us look at the penalties per game.  [Note: I grabbed all my numbers from the ESPN play by play, which is inconsistent in matching the numbers shown in the box score.  There may be a couple penalties that are missed, but it should still paint a good general picture.]

The bad news is that the general trendline shows that penalties are getting worse, not better.  USC’s season low for penalties called against them is the Cal game.  However, USC immediately follows that game up with a season high 14 penalties.    Now let us look at the penalty yards per game.

As you can see here, the general look stays the same as the last chart.  Some peaks that are not as high, which implies less penalties of the 15 yard variety and instead closer to the 5 or 10 variety in those games.  The general trendline of the graph still shows an increasing trend for penalty yards per game.  However, let us look at the average yards per penalty by game.

As you can see here, the general trend is that USC is slightly decreasing the yards  per penalty.  This decrease in yards per penalty likely means slightly less personal fouls for 15 yards but more things such as holding for 10 yards.

Now let us break it down further and look at the penalties based on phase of the game (offense, defense, special teams).

As you can see here, the offense is typically the worst offender by quite a bit.  That peak at midseason is quite disconcerting.  Looking at the trendlines shows that the offense is slowly increasing their penalties and defense is also quite quickly increasing its penalties.  The positives is that USC’s home games were all in the lower portion for penalties, especially on offense.  Will the coming home games show a similar low penalty count or will the trend continue?  I suspect the offense will get better at home due to less false starts, but we shall see.  Now let us look at penalty yards per game based on phase.

This shows a slightly different picture.  When looking at penalty yards, offense and defense square off for worst offender (other than the Utah and Washington games in which the offense really did poorly).  Since we know the offense commits a higher number of penalties from the last chart, this implies that the defensive penalties are generally for more yards.  The offense is probably committing penalties such as false starts (5 yards) whereas the defensive penalties are more like personal fouls or pass interference (15 yards).

Upon further review, the offense averages 7.4 yards per penalty while the defense averages 10.6 yards per penalty.  Breaking it down further, we can look at the number of penalties for each yardage category (5 yard, 10 yard, 15+ yards) based on the phase.

As you can see here, the offense commits by far the most five yard penalties.  This is not surprising as there were 21 penalties that were either false start or delay of game penalties.  However, the offense only committed 6 penalties of the 15 yard variety while the defense committed 14 of them.  In terms of personal fouls, the offense committed five personal fouls while the defense committed nine of them.

Most Committed Penalties

The most committed penalty on offense was false start with 14 flags thrown (31.8% of USC’s offensive penalties).  Next comes holding with 20.5% and then delay of game coming in at 15.9%.  Personal fouls accounted for 11.4% of USC’s offensive penalties.

The defense’s most committed penalty was personal foul, accounting for 45% of USC’s defensive penalties.  Offsides comes in next with 25% of the penalties and pass interference coming in at 20%.

Special teams also had their most committed penalty being personal fouls.  These accounted for 26.7% of USC’s special team penalties.  Offsides and holding were tied for the next highest with 20% each.

Effects on Offensive Scoring

I went into this post wanting to see how penalties affected scoring opportunity for USC’s offense.  Is it a coincidence that this offense, which returns many of the key components from last year, is struggling as penalties increase?

I decided to track every drive that USC had this season.  I then calculated the touchdown percentage and also the scoring opportunity of drives.  I define a “scoring opportunity” as any drive ending in a touchdown or a field goal attempt.  I consider it a scoring opportunity even on missed field goals since it is the offense’s job to get within field goal position, not to kick the actual field goal.  I then split up the drives based on whether there were penalties and how many penalty yards were in that drive.

To begin with, I counted exactly 100 drives for USC this season.  34 of them ended in a touchdown (34%) and 43% of them ended in scoring opportunities.  If we only count the drives without any penalty yards, we get 71 total drives with 24 ending in touchdowns (33.8%) and 29 ending in scoring opportunities (40.8%).  This is pretty close to the overall count.  Conversely, there were 29 drives which had penalties with 10 of them ending in touchdowns (34.5%) and 14 ending with scoring opportunities (48.3%).  The numbers surprisingly didn’t get affected much by the penalties.  In fact, these numbers imply that penalties cause a higher scoring rate, which goes against all logic.

I decided to look at drives which only included 10 or more penalty yards as singular false starts may not affect the end result of the drive very much.  There were 15 drives which had 10 or more penalty yards in them.  Only three resulted in touchdowns (20%) and seven resulted in scoring opportunities (46.7%).  Furthermore, there were 10 drives which had 15 or more penalty yards and only one resulted in a touchdown (10%) and five in a scoring opportunity (50%).  See the chart below.

The data implies that a singular 5 yard penalty does not have a large overall impact on scoring touchdowns, but once you get 10 or more penalty yards, it drastically affects the offense’s ability to get into the endzone.  The data also strangely implies that getting penalties helps get within field goal position.  This may be an artifact due to penalties around the redzone that stall potential touchdown drives and instead make USC settle for a field goal attempt.  It should be noted that the sample size is pretty small here, and we could also just be seeing the effects of that.

Effects on Offensive Conversions

Taking it a bit further, I decided to track the percentage of success for conversions.  For every set of downs, I tracked if the team eventually converted for a first down (or touchdown).  Again, I tracked this based on whether there was a penalty or not and how many penalty yards there were.  The idea is that smaller penalties may not affect the big picture drive if the team is in good position to convert a first down anyways.  Once the first down is converted, there isn’t much long lasting effects on the drive itself other than extra yardage that they must get to score overall.

There were 203 sets of downs which had no penalties attached to them.  USC converted for a first down on 153 of these sets (75.4%).  This is a pretty good conversion rate.  Conversely, there were 34 sets which included an offensive penalty in them.  Of these, USC only converted 17 of them (50%).  Furthermore, 13 sets had penalties of 10 or more yards, which only four were converted (30.8%).  Five sets had penalties of 15 or more yards, which only one converted (20%).  This data pretty clearly shows a rapid decline when trying to get that first conversion after a penalty.

Effects on the following Offensive Play

I decided to do a quick check to see if penalties affected the play immediately following it.  The thought processes was whether there was any psychological effect on the players when they are forced to walk backwards.  I tracked the average yards per play immediately following a penalty and compared that to the average yards per play of USC.  What I found was that USC averages 6.94 yards per play normally and 6.70 yards per play immediately following a penalty.  Not a whole lot of difference.  This data most likely means there is either no or minimal effect on the next play.  It could also mean that any psychological effect is generally offset by the play call trying to get extra yardage (to make up for the penalty).

Quick Notes on the Effects on Defense

When I was gathering the stats, I was mostly gathering the stats for offensive purposes.  However, I did gather one defensive stat which is worth mentioning.  Of the 22 defensive penalties I tracked, five of them (22.7%) occurred on 3rd or 4th down which allowed the opposing defense to get an automatic conversion.  These are drives which would have otherwise been stopped had it not been for the penalty.  I did not count it if the opposing offense gained enough yards to convert without the penalty.  Two of these five penalty-aided drives lead to touchdowns.  One of those penalty-aided touchdown drives was against Arizona and could have helped decide the final outcome game.


Penalties hurt.  They slow drives down and cause them to stall.  They hinder the ability to score touchdowns.  They help opponents sustain drives.  This USC team has been uncharacteristically undisciplined.  I wanted to see if these penalties were being generally called on younger starters rather than our returning veterans, but unfortunately ESPN’s play by play does not usually list the penalized player.

I believe that these penalties have been a large contributor to USC’s weakened offensive output.  Combine the penalties we had against Arizona with a -4 turnover margin on the road and you’re going to lose the vast majority of the time.  It is surprising to me that the score margin was only 3 points given all that went against us.  However, USC will need to play more disciplined and greatly reduce the number of penalties if they want to have any chance upsetting Oregon this weekend.  I am hopeful, but given our trends I am not expecting too much in terms of drastic penalty improvement.  We will see if this USC team can overcome their own ways and get us a win at home.


One response to “A Look at Penalties

  1. These charts are the visual evidence of this season’s record of poor execution and undisciplined play. Good work and thanks.

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