I think what they are saying is the kind of tests they see in a corporate environment are not the kind that add any value to the refactoring process (or worse, inhibit it).
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.
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).