With the recent changes to thetouch-back rules taking effect this 2016 NFL preseason, one can begin to probe
the data for trends in both returner and kicker strategy. To this end, a python script was written to
scrape the play-by-play data from the 2015 and 2016 seasons for every instance
of the word “kicks” or “kickoff” from the ESPN play-by-play data. The result was 604 and 556 respective
kickoffs from 2015 and 2016 preseason games.
After excluding onside kicks (9 and 6 respectively), kicks that were
called back due to penalty (3 and 4 respectively), and kicks from locations
other than the 35 yard line (18 and 19 respectively), we’re left with 574 and
527 standard kick-offs in 2015 and 2016 respectively:
Year
|
G
|
KOs
|
Onside KOs
|
From non-35
|
No Play
|
Standard KOs
|
Returns from EZ
|
Returns from field
|
Touchbacks
|
OOB
|
2015 Pre
|
64
|
604
|
9
|
18
|
3
|
574
|
220
|
87
|
261
|
6
|
2016 Pre
|
64
|
556
|
6
|
19
|
4
|
527
|
156
|
142
|
229
|
0
|
We can now compare the average
starting field position (FP) following pre-season NFL kicks between 2015 and
2016:
Starting FP of
"standard" KOs
|
||||
Year
|
Kicks
|
Avg.FP
|
SD.FP
|
p-value
|
2015
|
574
|
20.8
|
7.3
|
< 0001
|
2016
|
527
|
23.1
|
7.5
|
|
It’s no surprise that the average
starting field position is significantly different after increasing the
touchback spot by a full five yards, but it is interesting that the difference
is only 2.3 yards. Furthermore, we can
compare the field position in 2016 of kicks into and out of the end zone (EZ):
Starting FP by EZ kick
location in 2016
|
||||
Year
|
N
|
Avg FP
|
SD
|
p-value
|
Kick to EZ
|
382
|
23.3
|
7.3
|
0.364
|
Out of EZ
|
145
|
22.6
|
7.8
|
|
Though the difference is not
statistically significant, a kick short of the end zone yielded 0.67 fewer
yards (2 feet) this pre-season. In
preseason games, players are vying for a roster spot and are likely being instructed
to return kicks at a higher percentage than we should expect in the regular
season. To this end, let’s examine the
return and kick rates:
Returner Decision
|
Kicker Decision
|
|||||||||
Year
|
Stat
|
Kneel
|
Return
|
p-value
|
Year
|
Stat
|
out of EZ
|
Kick to EZ
|
p-value
|
|
2015
|
freq
|
261
|
220
|
0.124
|
2015
|
freq
|
87
|
481
|
< 0.0001
|
|
rel %
|
54.3%
|
45.7%
|
rel %
|
15.3%
|
84.7%
|
|||||
2016
|
freq
|
229
|
156
|
2016
|
freq
|
142
|
385
|
|||
rel %
|
59.5%
|
40.5%
|
rel %
|
26.9%
|
73.1%
|
|||||
Indeed, the 5% bump in touch-back
rate may only be a difference due to random noise. However, the 11.6% increase
in kicks short of the end-zone is a big enough difference to prove a systematic
difference between kicker behaviors between 2015 and 2016. As the informed reader knows, preseason is
about the process of player evaluation and may not be reflective of regular
season trends, so kickers and returners may do drastically different things
next week, but rest assured that this data will be evaluated in a prospective manner as the season unfolds.