The Patriots Have Incredible Ball Security
For whatever reason, the Patriots do have exceptional ball security, especially for an outdoors team. And I mean exceptional.
I was intrigued by a link sent to me via Twitter at Sharp Football Analysis, a handicapping site. The article demonstrated that NE's ball security was an outlier to the tune of several standard deviations. The charts are convincing, and the implication is that NE benefitted from under-inflated balls is unmistakable. But I wasn't sure how much stock to put in the numbers for a couple reasons. One is that they were so extraordinary they seemed unlikely to be true. And second, the analysis used plays per fumble as its basis rather than fumbles per play. For low-rate events, like fumbles, outlier cases can appear exaggerated depending on which way you look at them.
I started by verifying the numbers. They may vary slightly because I'm including playoff games, but overall the numbers look correct. The article looked at both fumbles lost and at total fumbles. I'd submit that if we're talking about ball security, fumbles lost is just total fumbles + noise, so let's just focus on total fumbles. Here are the offensive plays per fumble for each team in each season since 2010:
<snip>
NE ranks third over that period. Very good, but nothing out of the ordinary. You'd expect teams with good QBs and good offenses to have fewer strip-sacks. But the article linked above makes a good point: Many teams that play indoors are concentrated at the top of the list. Let's see how the table looks if we exclude dome teams.
http://www.advancedfootballanalytics.com/index.php/home/research/general/224-the-patriots-have-great-ball-security
Something I found interesting, the timing is bad but I haven't visited the site at all following the conference championships but I should have realized they'd have the best deflate-gate analysis there is.
This was a follow-up to the above article -- it is long so I'll snip the middle parts. It is also much better with more details & analysis, I recommend reading top to bottom.
A Last Look at NE's Fumbles
<snip>
READ THIS IF YOU WANT TO BELIEVE NE IS INNOCENT
NE is not an outlier in any sense. They are actually #2 on the list after ATL for the period since 2006. There are other teams with nearly as impressive over-performance as NE for several-year stretches, such as ATL, IND, and DET. Should we also be investigating ATL for ball tampering?
You can see that the model used may not completely account for QB "eliteness." Brady's best years came since 2007, and you can see the Manning-led Colts had impressive fumble over-performance for a certain period. Drew Brees' Saints seem to have a similar pattern.
NE actually had 3 more fumbles than we'd expect in 2013, breaking the string of consecutive seasons with fewer than expected fumbles.
<snip>
READ THIS IF YOU WANT TO BELIEVE THERE'S SOMETHING FISHY GOING ON
NE is #2 since '06, but is #1 since '07, #1 since '08, #1 since '09...you get the picture. The string of consecutive seasons of over-performance is unmistakable. One year where they might be nipped by randomness (and just barely) does not mean they don't have an advantage.
Besides, the standard here isn't that unless NE is an extreme outlier they are in the clear. It's misleading to imply otherwise. The standard should be: which explanation is the data most consistent with? The tables above show that the data is exactly what we'd expect if a team had an advantage but extremely unusual and unlikely to be observed by chance alone.
Regarding ATL, yes, they are also very good with ball security. Should they be investigated too? Possibly, but I wouldn't start an investigation or make an accusation on statistics alone. The bottom line is that nothing here rules out the possibility other teams also tamper with their footballs.
http://www.advancedfootballanalytics.com/index.php/home/analysis/team-analysis/227-a-look-at-ne-s-fumbles
FWIW -- the first Deflate gate post
Deflate-Gate and PV/T=k
This Deflate-Gate controversy had me thinking about 9th grade chemistry and wondering about the effect of temperature on the balls. I saw that CAR kicker Graham Gano recently tweeted that he is often frustrated by how the balls naturally lose their air pressure when going from an indoor setting, where the inflation pressure is set and checked, to a cold outdoor setting. Could NE's balls have lost their pressure due to the temperature?
We'll need to dust off the Combined Gas Law to figure this one out. That's the physical law that says gas temperature, pressure, and volume are all related. Pressure and temperature are directly proportional--As temperature goes up, pressure goes up proportionally and vice versa. Pressure and volume are inversely proportional--as volume expands, pressure decreases and vice versa. And so it follows that volume and temperature must also be directly proportional. Put mathematically, we can say that for a given mass of air, the ratio of product of the pressure and volume and the temperature must remain constant.
PV/T = k (where k is a fixed constant)
If we change any one of those variables, we can solve for the others. Because k=k, we can write:
P1*V1/T1 = P2*V2/T2
<snip>
ssuming V1=V2 (the ball does not significantly grow between 10 and 13 psi) and that no deflation occurred, the mass of air remained the same and we can write
(12.5+14.7) * V1 / 294.3 = P2 * V2 / 283.7
Since V1=V2, they cancel out. Solving for P2, we get 26.2 absolute psi, which is 11.5 gauge psi. That only explains a half of the discrepancy, and there's still 1.0 psi left to account for. But the volume of the ball does change when inflating, which is the whole point of deflating it to make it easier to hold, throw, and catch. But it only does so slightly in that range of pressure, probably by a few percent. And a shrinking ball would have the effect of mitigating the loss of pressure.
Any warming that may have occurred during halftime when the balls were re-examined would reduce the effect of temperature, and leave more of the discrepancy unaccounted for. Certainly, a full half of play might deflate the balls, but 11 of the 12 were under-pressurized, so I doubt that would explain it. Some balls would be affected much more than others depending on what kind of abuse they get.
http://www.advancedfootballanalytics.com/index.php/home/research/weather/222-deflate-gate-and-pv-t-k
= new reply since forum marked as read
Start posting articles about the Seahawks MAKING THE WORST PLAY CALLED BY THEIR COACH.
Which, according to the analysts kissing their asses all week, are now saying it will go down as one of the worst calls in history. 
Well, congrats to both teams....it was a great game. Sad to see some bad sportsmanship at the end, but I guess when you thought you had the game in the bag and all the bad rap the Pats get, your ego might get deflated.
Expected since they won. Yay! 
Great skill on both sides of the field. Loved every second of it - even the ones that made me cringe (Brady's INTs, and yet another miracle catch!)
Except for loving the ones that made you cringe. 
I knew it would be tough but damn, what a finish!
