

The New England Patriots’ prevention of fumbles is nearly impossible - _pius
http://www.slate.com/articles/sports/sports_nut/2015/01/ballghazi_the_new_england_patriots_lose_an_insanely_low_number_of_fumbles.html

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jsyedidia
If you watch Patriots games, you'll see that if Patriots running backs fumble,
they get benched. If they do it again they get released. Belichick is maniacal
about getting on his players about fumbling. That is a simple explanation. The
team has been well-coached for a long time. If you think the Patriots' success
is all from deflated balls, you need to explain how they out-scored the Colts
28-0 in the second half (and didn't fumble in horrible conditions).

~~~
fecak
Over the past two seasons there have been 9 total fumbles by Patriot running
backs - only 1 all this year. All of those backs are still employed by the
Patriots. Over those two seasons, the majority of fumbles came from Brady and
Edelman.

Of the backs that fumbled in 2012, only Woodhead is gone. He fumbled only
once.

Two backs fumbled in 2011, once each. Woodhead (who is gone) and Ridley, who
is still a Patriot.

Patriot backs simply don't fumble. Brady and Edelman do, and Welker did a bit.
Your explanation isn't supported by the data.

Source. [http://www.pro-football-
reference.com/teams/nwe/2014.htm](http://www.pro-football-
reference.com/teams/nwe/2014.htm)

EDIT - I'm not sure my source differentiates fumbles from lost fumbles,
although that doesn't seem to impact the conclusion regarding parent's
comment.

~~~
jsyedidia
"Patriots backs simply don't fumble": Yes, because if they have a fumbling
problem, they stop playing until they fix it (Ridley) or they cease being
Patriots if they can't fix it (Maroney). Belichick is well-known for having a
"doghouse" for running backs who fumble.

"Your explanation isn't supported by the data": I wasn't trying to give an
explanation supported by the data. I was trying to give an explanation for the
data that makes sense and is supported by observing the Patriots play.

It's like saying Magnus Carlsen must cheat at chess, because the chance of him
making so few errors is effectively zero assuming he makes errors at the rate
that other grandmasters do.

~~~
tbrake
I think it would be pretty easy to show, similar to this article -

Pre-computer era elite GMs and computer-era elite GMs have similar error
rates[1], with the caveat that we presume disagreeing with the computer's top
choice to be an error. They mostly agreed with the computer's assessment
something like 50-57% of the time.

As far as I know Magnus' games haven't been subjected to this kind of
analysis, and I recall 2 pretty bad moves in the recent match with Anand, so
I'd be interested to see it. I suspect he may be even slightly above 60%.

Should it be something like high 70%'s though I think it would be time to
start a conversation about it. It's how Ivanov was busted: overwhelmingly
playing one of the top 2 engine moves, which is basically impossible. [2]

1 - [http://en.chessbase.com/post/computers-choose-who-was-the-
st...](http://en.chessbase.com/post/computers-choose-who-was-the-strongest-
player-)

2 -
[https://www.youtube.com/watch?v=Jr0J8SPENjM](https://www.youtube.com/watch?v=Jr0J8SPENjM)

------
asynchronous13
I'm becoming more disappointed in this analysis.

"But in 2007, something happened to propel [the Patriots] to a much better
rate."

The author is using a 5-year average, and then concluding that something must
have happened in a single year that is suddenly different. What that implies
to me, is that they had a particularly terrible year in 2002. So, when the
really bad year slides off of the 5-year moving average, then the 5-year
average suddenly looks much better.

~~~
twoodfin
Also, while the article ultimately looks at both, the "money chart" is for
fumbles lost, rather than total fumbles. I'm pretty sure the stat guys at
footballoutsiders.com have more than once run the numbers to show that fumble
recovery is pure chance; hard to see how having easier to handle balls
increases those odds.

------
robryan
As someone who doesn't follow the NFL I am surprised that they allow the teams
to supply their own balls. Seems it would be less complicated and achieve an
even playing field if everyone had to use the same balls supplied by the
league.

Does this happen in baseball/ basketball as well? From an Australian
perspective it seems unusual.

~~~
skwirl
Quarterbacks like their footballs to be broken in a bit, and they all have
their own preference for doing it. They lobbied the NFL years back to let them
break in the game footballs and the NFL said OK. They have to use official NFL
footballs and they are SUPPOSED to be properly inflated at game time. Each
team uses their own footballs while on offense.

I doubt this happens in basketball because the same ball is being handled by
numerous people on both teams, so it wouldn't be fair to let one player or
team break the ball in to their own preferences. The same would be true of
your AFL. In the NFL, teams are using their own broken in balls, and the
quarterback is (usually) the only guy who has to actually throw it.

Baseballs only last a couple of pitches and offense/defense are completely
different games, so I seriously doubt anyone is allowed to do anything to any
ball before the game. When a pitcher gets a new ball it is already pre-rubbed
in a special mud, and they can rub it in dirt a bit but they can't put
anything that will stick to the ball on it as it gives the pitcher an
advantage.

------
itsdrewmiller
plays per fumble is not a very good metric - as fumbles go down it increases
exponentially. If you look at the total fumbles, the patriots are #1 but only
7 ahead of #2. The two worst teams are 10 behind the next two teams. I didn't
run the numbers, but eyeballing it, it seems like the Patriots are pretty
easily within a couple standard deviations there.

~~~
donchipotle
I think Brian Burke did a more thorough take on it.

[http://advancednflstats.com/index.php/home/research/general/...](http://advancednflstats.com/index.php/home/research/general/224-the-
patriots-have-great-ball-security)

It's not as damning for the Patriots. But very interesting that it suddenly
started in 2007, the same year the NFL changed the rules to allow visiting
teams to use their own balls.

~~~
chockablock
Thanks this is a much more mathematically reasonable analysis. I especially
like the idea of using the #fumbles made by Pats' opponents as a control for
the weather (although that confounds the Pats' defense's ability to generate
fumbles).

The OP gets credit for noticing an unusual trend in the data, but does all
kinds of weird seat-of-the-pants analysis that I found pretty hard to even
look at.

E.g. Sorting the teams by fumble frequency, and then running a regression on
the ranked list (!!?); using plays/fumble instead of fumbles/play; reporting
stats with the null hypothesis that the Pats fumble rate is drawn randomly
from other teams (instead of asking what the likelihood is of an extreme value
at least that high).

------
Anechoic
For those of you who aren't keeping up with the up to the minute minutae of
the New England Patriots (American football team) scandal (presumably because
you have lives), head coach Bill Belichick gave a press conference a few hours
ago where he provided a hypothesis of what might have happened: as many people
know, quarterbacks like their game footballs prepared in specific (sometimes
elaborate [0]) ways prior to use in games. Belichick says that the team went
over the process they use for games a few days ago and they determine that the
preparation process they use for their footballs (which he claims they do
right up to the point they are given to officials for pre-game testing)
increases the air pressure in the balls by about 1 psi [1]. Therefore, the
balls appear legal when tested by officials, but after a few hours of sitting
around, the pressure reduces to below the legal limit. He doesn't specify the
process used by the team, but presumably it's some kind of rubbing that heats
the ball up, and when it cools down the interior air pressure is reduced
accordingly.

I'm sure someone will test this out and verify or discredit the claim.

[0] [http://www.nytimes.com/2013/11/24/sports/football/eli-
mannin...](http://www.nytimes.com/2013/11/24/sports/football/eli-mannings-
footballs-are-months-in-making.html?_r=0)

[1]
[http://www.boston.com/sports/football/patriots/extra_points/...](http://www.boston.com/sports/football/patriots/extra_points/2015/01/bill_belichick_defends_patriots_on_deflategate_we.html?p1=feature_pri_hp)

~~~
zaroth
Going from 75 degrees to 50 produces something like a 1.5 psi reduction. 85 ->
35 wound be closer to a 2psi drop. Water vapor increases the drop. Funny thing
is searching for the calculation produces highly variable results.

~~~
axiak
Belichick specifically said he was not talking about atmospheric temperature
conditions, but the conditions of the ball. Presumably whatever rubbing of the
ball was necessary for preparation heated the air in the ball. He must have
explained this in the most obtuse way possible to reduce the chance people
call him a cheater for heating the air in the ball.

------
jonjenk
Analyzing outlying statistics across all the available variables would be an
interesting technique to try to predict other potential rules violations. This
could apply to many different types of sporting events.

I wonder if anyone is working on this problem?

Despite a few nit picky issues I have with this particular analysis of the
Patriots fumble data it's probably the strongest evidence I've seen so far
that there has likely been a persistent rules violation.

~~~
Anechoic
_it 's probably the strongest evidence I've seen so far that there has likely
been a persistent rules violation._

That's only true if ball inflation tracks with fumbles. There have been lots
of assertions that's the case, but I haven't seen any evidence.

Two counter examples:

\- If you look at AFCC, that's Patriots had 1 fumble in the first half playing
with an underinflated ball in dry weather conditions, and had zero fumbles in
the second half playing with properly inflated balls, and in wet conditions.

\- Aaron Rodgers is on record stating that he likes his footballs to be
inflated as high as possible. But if you look at GB's fumble data in the link,
they're #6 behind NE in total fumbles.

There are a whole bunch of confounding variables here, including coaching
techniques (look at how Tiki Barber's corrected his fumble problems in one
year after coaching changes).

~~~
jonjenk
I agree that we don't have a controlled study in this case. However, it will
be interesting to look at this data at the end of next season. If the Patriots
fumble stats revert to pre 2007 levels it will certainly raise some
interesting questions.

~~~
twoodfin
Why? Fumbles are rare and highly variable.

------
asynchronous13
I'm not convinced that it's okay to just remove all the dome-teams from the
plot. Using the author's data, here's a plot of all the teams and total
fumbles (not 'fumbles lost' that the author focuses on):

[http://i.imgur.com/QP6LXWg.png](http://i.imgur.com/QP6LXWg.png)

The Patriots are not even the top team! It's actually the Falcons that have
the most plays per fumble. If it's "nearly impossible" for the Patriots, what
does that say about the Falcons? The author focuses on "fumbles lost" because
that number is more dramatic if one is trying to prove that the Patriots did
something wrong. That number in isolation only shows that the Patriots were
extremely good at recovering their own fumbles.

Looking at the graph, there is a notable bend at the top 4 teams. Either the
top 4 teams have fewer fumbles through training, or the top 4 teams are all
cheating somehow. It's hard to call the Patriots statistics impossible when
they're in 2nd place.

------
abram
It would be interesting to get the stats on fumbles during kickoff/punt
returns (when a neutral kicking ball is in use, not a team-supplied offensive
ball), and on plays involving interceptions or fumble recoveries (where they
would be using the other team's ball). If they rank highly in fumble
prevention in those situations, it would suggest that this is a result of
coaching, not using a particular ball.

~~~
fecak
Kickoff and punt return fumbles can be the result of other factors - players
traveling at high speed over a long distance hitting a returner looking
skyward is a unique football situation that only occurs on returns.

Interceptions and recoveries would be by defensive players, who would spend
much less time focusing on ball handling since they rarely carry the ball.

------
ragtimepiano
Listen, engineers and scientists: 11 out of 12 balls, markedly different and
underinflated compared to the other team's balls? This is a priori evidence of
tampering. Any jury would convict. We don't need a Perry Mason-type
confession; we don't need to identify the culprit. The team should be strongly
punished for breaking the NFL rules. I think the NFL should do an extensive
investigation, after the initial punishment, which justly would be done BEFORE
the Super Bowl. This investigation needs to determine whether the Pats have
cheated with underinflated balls over a period of months and years. It can be
done. Then is the time for scientific analysis, testimony by physicists, and
so on.

My point is: We don't need to identify the person responsible, and we don't
need a confession. Guilt is obvious, a priori. Punishment should be swift.

------
xofer
Is the author confusing "fumbles" and "fumbles lost" or am I?

~~~
asynchronous13
The author starts out with a plot of lost fumbles, and further down shows a
plot that includes all fumbles, not just lost fumbles.

------
_croz
Wouldn't pass completion ratio be a better metric?

------
mrwarn
The game against the Colts the Patriots clearly cheated. It is beyond
reasonable that 11 of 12 footballs are 2psi less than the rule allows.
Especially since the 12th football of regulation weight is the football used
for kicking as you want the football inflated properly. But using fumbles as
proof of long term violation is tough because their are too many factors to
consider. Patriots are a pass heavy team and have been for a long time. They
use multiple RB's and a fresh RB is less likely to fumble than one RB used
heavily throughout the game due to mental and physical fatigue. WR's fumble
but are less likely than RB's. An under-inflated ball is easier to grip so it
would be interesting to see how WR's who left have fared on their new teams
and if any returned later, after playing poorly on new team, to play well for
the Patriots. Since 2007 has Tom Brady's completion % and interception ratio
on the road improved drastically? All these things could be explained by an
under-inflated but not definitively.

~~~
joshuapayne
You are incorrect with respect to your explanation of "the 12th football being
used for kicking". An entire separate group of footballs are used for kicking,
outside control of either team. The kicking balls are brand new and are not
allowed to be broken-in. They still have the waxy coating a new ball has. This
was done some years ago to try to reduce the effectiveness of kickers.

~~~
mrwarn
I stand corrected, I didnt know that tidbit and just assumed that the 12th
ball was for kickoff/field goals. But what about punting is it the same ball
used for kicking or would it be part of the 12?

~~~
etrevino
Punting balls are also the special kicking balls.

