May 26, 2018

Clemson Minute – #3 Third down defense was great in ’15, but can ’16 unit match that standard?

Clemson finished fourth in the nation in 3rd down defense in 2015 and one area where the Tigers stood out was third and short. How good were the Tigers on third and short and how important is it that the Tigers duplicate or at least approach those numbers this season?

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Friday Numerology

A weekly look at the important numbers.

Third Down D – Conversion rates, averages and who makes stops

Below are the numbers for third down defense on the season.  Notre Dame faced an average distance to go on 3rd down of 10.8 yards and for the season Clemson opponents have averaged 3rd and 8.6 yards to go.3rd Down D 2015 4

Here’s who’s making those stops on third downs to prevent first downs.
3rd Down D Tackles 15 4

Third Down D

The Tigers picked up right where they left off in some ways, by allowing only a 25.0% conversion rate on third downs against Wofford.  One difference from 2014? 3rd and long gave Clemson some issues, while they were perfect on 3rd and 6 or less.

3rd D by Distance 2015 1

Tigers led nation in 3rd down D in ’14 and the reason is…

The key to leading the nation in 3rd down defense?  Being really good on 1st and 2nd down defense.

It turns out that Clemson’s opponents faced 3rd and 7 or more on 61% of third downs in 2014 and, as the chart/graph shows, there wasn’t much chance of succeeding when faced with that distance – 14.2% to be exact (17/120).
3rd Down D Graph3rd Down D Chart

When faced with 3rd and 6 or less opponents approached 50% conversions (37/77 – 48.1%).

It’s not earth shattering to note that the farther to go the more difficult it is to make a first down – that’s intuitive.

Perhaps the takeaway here is as good as the 2014 defense was even that group struggled (to some degree) when the distance to go was 6 yards or less and the key (in addition to a fast, athletic, talented defense) is stopping first and second down thereby forcing a more predictable play call on 3rd and long.

Third Down Conversions with Stoudt on Field

Of the many differences between Deshaun Watson and Cole Stoudt one that sticks out to me is third down conversion percentage.  While Watson’s is over 50%, Stoudt’s is hovering around 35%.

Below are the detailed numbers for Clemson while Stoudt is on the field.  This number is slightly different than those listed in the quarterback drive chart for Stoudt because that chart includes only drives in which Stoudt began and ended the drives and this one includes all third downs Stoudt was on the field for.  Remember, Stoudt took over drives that Watson began three times this season – Louisville, Georgia Tech and South Carolina.

Third Down Conversions Stoudt on Field 2014 12

Third Down Conversions – Both Sides of The Ball

Third down conversions by distance for Clemson offense and defense.

Apologies for the size of the graphs, but wanted to include visual representation of data in tables.



TDC O Graph 2014 11TDC O Chart 2014 11TDC D Graph 2014 11TDC D Chart 2014 11

Boyd Saves Drives with Legs


There’s not a lot to add to the numbers below. In this case they pretty much speak for themselves.  Tajh Boyd kept drives alive with his legs on third downs in 2012.  67% of the time Boyd either gained a first down or scored a touchdown, a rate nearly twice that of the 2011 season.

Boyd 3rd Down Rushes

With 7:07 left in the third quarter in the Chic-Fil-A Bowl Clemson took over on it’s own 23 trailing 24-16. Two plays netted 9 yards and the Tigers faced a third and 1 at their own 32.

Boyd gained three yards on that third down and the Tigers went on to score, pulling within 2 points.

We all know what happened after that.

I’ve included each of Boyd’s 3rd down runs for the 2012 season below. Because of the size you’ll have to scroll side to side and up and down to see the entire entry.

If you don’t believe me, just ask Boston College linebacker Steele Divitto, who got a face full of Tajh on this third and 10.

Geek Speak: The Effect of 3rd Down Conversion % on Points and Wins

In previous posts we’ve learned about the Pearson Correlation Coefficient, what it means and how it can be applied to analyzing a football team’s performance.

We’ll continue down that road today by looking at the correlation between successes on third downs (both offensively and defensively) and what that means to points and wins/losses.

Correlation between offensive 3rd down conversion %, points and victories:

0.696052 0.529742015

First, looking at the 2012 NCAA third down conversion statistics on the offensive side of the ball there is a correlation between success on third downs and points scored – a strong correlation of 0.696052, which can be seen in the chart below and the slope of the line through the data.
3rd and Points

When we look at how third down conversions affect wins and losses we see a correlation, but not as strong as the correlation to points. Notice the slope of the line is not as great as in the picture above. Why? Because the offense has a large degree of control of how many points a team scores, but has less direct control over how many points the opponent scores thereby decreasing the correlation between wins and offensive third down conversions.

In short, the offense alone does not control wins and losses (brilliant!).
3rd and Wins

On the defensive side (graphs not included), the correlation of third down conversion percentage to points is strong, but less than on the offensive side, which is an interesting note and one that we will see again and again when analyzing correlations.

Correlation between defensive 3rd Down %, points and wins:

0.60035 -0.44608

Notice the negative correlation to wins which makes perfect sense. The higher percentage of third down conversions a defense allows the fewer wins a team is likely to have.

None of this is rocket science and most fans are probably wondering why I took the time to research and write this post.

First, it’s what I do. Secondly, while we knew that third down conversions affect points and wins and losses, we had no idea how much. Now we know.

Finally, and this may be the key takeaway going forward, using the data above we can argue that third down conversions are more important on offense than they are on defense, both in terms of points and wins.

Not all third downs are created equal. Assuming everything else is the same, the offensive third downs are more important than defensive third downs and this is important because of the implication that revelation has on “defense winning championships”.

As we’ll see in coming posts, this isn’t the only metric that contains this nugget.

Play Counting

In general, I have not been a proponent of the “80+ plays = a win” club.  My own tracking of statistics for college football as a whole over the course of multiple seasons show that the average number of plays between winning teams and losing teams is small.  Many teams that reach 80 or more plays lose.

I did, however, think that the number of plays Clemson ran against South Carolina was important enough to make it my “Keep An Eye On” topic and for once I hit the nail on the head. 

The inability to sustain drives doomed Clemson on November 24th.  Clemson had the ball 4 times in the second quarter with the lead and had “drives” of 5, 5, 5 and 4 plays and 0 points. 

Clemson ended up running 59 plays in a 27-17 loss against the number 11 defense in the nation.


Play Counts

The Tigers have been prolific against defenses ranked outside of the top 25, averaging 88 plays per game.  When faced with more talented opposition Clemson averages only 70 plays – 20% less. (Only FBS defenses used in averages)

The numbers drop similarly when comparing wins and losses – Clemson averages 84 plays in wins and only 68 in losses – a 19% difference.

When Clemson runs 80 plays they are 7-0.  When they don’t they are 3-2 and more importantly 0-2 against top 11 defenses.  LSU is ranked 8th in total defense.

These numbers make it imperative that Clemson approaches 80 plays on New Years Eve.  This is not an impossible task as the Tigers ran 77 plays against a pretty good Florida State defense in Tallahassee in game 4.

It’s not unusual to see a dip in plays run against better ranked defenses. To the contrary, that’s part of how the lofty ranking was obtained. But the difference in the South Carolina game was pronounced.

It’s true that the defense had trouble getting off the field in the second half as South Carolina dominated in time of possession and plays run.

On the other hand – if Clemson could have extended just one of the 4 drives in the second quarter when they had the ball and the lead, they very easily could have gone up by two scores at the half and the second half may well have been different.

The numbers are pretty clear for this years Clemson Tigers. The closer to 80 plays they get in Atlanta, the better chance they have of winning.