Placing Fumbles in Context (Part 1)

The official statistics published by the NCAA list fumbles under the 'turnover margin' section.  For Nebraska, it records 22 fumbles lost (YIKES!) for 2012.  And that's basically it.  Other than to elicit the obvious response of "damn, that's a lot of fumbles" there isn't much more useful information there.

However, with a little digging I was able to come up with some more specific data on fumbles from 2010-2012 that helps place fumbles into a better context within the space and time of the game.

First, let's look at the types of plays that teams were running when fumbles occurred. There are really only four kinds of plays that can result in a fumble: rush (duh), reception, KO returns, and punt returns.

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Imagine that a team is moving the ball from right to left...or from the South to North endzone if you're sitting in the pressbox at Memorial Stadium. Fumbled KO returns accounted for about 2/3 of fumbles in the endzone across the FBS, and it was about that for NU. Rush fumbles show a marked decrease as teams approach the end zone, but then increase significantly inside the 10-yard line. NU shows a similar trend. Generally, NU's fumbles appear to be similarly distributed by type and location as the rest of the NCAA's.

UPDATE - 2PM, 6 March

When I first wrote this analysis I failed to break down the actual number of plays (all plays) for each down.  Because of that, I may have drawn exactly the wrong conclusion about fumbles by down.

First down accounts for 38.4% of all FBS plays, but only 33% of fumbles.  That means that 1st down is actually the safest down when it comes to fumbles, rather than the most dangerous as I assessed yesterday.  Third down is slightly more dangerous, but the real fumble danger zone is 4th downs and punt returns.  Fumbles occur on 4th down and punt returns almost twice as often as they should if they occurred at the same frequency as the plays are run.

Down	NCAA Fum	All NCAA Plays
1	32.95%	38.42%
2	27.60%	28.73%
3	19.59%	17.96%
4	3.12%	1.88%
P	13.61%	6.16%
K	6.25%	6.85%
Grand Total	100.00%	100.00%

Using the methodology to calculated a 'lost points' value for turnovers I proposed in this post, the average 'lost points' for each play type looks like this:

Fumble Play	Ave Lost Points
KO Ret	-6.14
Punt Ret	-5.6
Rec	-5.71
Rush	-5.73
Overall Ave	-5.74

While the other play types have nearly identical average values, KO returns are different, and cost more on average.  While 1st and 2nd down are clearly the 'danger zone' for fumbles, the chart above shows that fumbles on returns are a not-insignificant portion of all fumbles, and considering the preponderance of return fumbles deep in an opponents' territory, I think this is presents strong evidence to justify spending extra time on safely fielding returns. 

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I was surprised when I first saw this chart and how clearly it illustrates that fumbles are more likely to occur on 1st and 2nd Downs than on 3rd downs. 

This can be accounted for somewhat by greater number of 1st and 2nd downs in a game, but I don't think that is enough to account for the entire difference. Something appears to be happening here. Does knowing that you have a fresh set of downs lend itself to a false sense of security? Are coaches calling riskier plays on 1st and 2nd downs? I don't know the answer, but it's worth looking into I think. 

 When I compare NU's by-frequency to the NCAA's, I see this:

Down	NCAA %	NU %
1	32.95%	27.08%
2	27.60%	27.08%
3	19.59%	25.00%
4	3.12%
K	6.25%	6.25%
P	10.49%	14.58%

Nebraska's fumbles are much more uniformly distributed across 1st, 2nd, and 3rd down situations.  They fumbled slightly higher percentage of punts than the NCAA average, and they had a significantly greater percentage of fumbles coming on 3rd down.  This may be another needed point of emphasis for the coaching staff to address in 2013.  While this analysis doesn't cover this, I suspect that this symptomatic of NU's generally poorer execution on 3rd down across all offensive areas.  Also, NU's fumble percentage for punt returns is even higher than the already-high FBS average.

Stay tuned for Part 2 where I'll break down fumbles by Distance-To-Go, Player Position, and Game Quarter.  

GBR!

As always, you can download the data supporting my analyses.

The I used data in this analysis from cfbstats.com and Rivals.com.

@paul_dalen