Two Infographics on Deflate-gate

Several sites are covering the story of deflate-gate with infographics. The gist of these stories is that in 2007 an NFL rule change went into effect that allowed each team to bring their own balls to games, both home and away. Prior to this rule the home team supplied the balls for both sides. Coincidentally, several stories go on to quote, Tom Brady was a big advocate of this rule change.

Assuming for the moment that Deflate-gate is true then might the pre vs post rule change data reveal the truth? The data collected came in two forms, both involved “touches per fumble”. If this metric confuses you, it might be easier to imagine “plays per fumble” where “stickier balls” would be fumbled less frequently. But plays vary widely in their ball-handling characteristics so “touches per fumble” is a better metric.

One metric merely compiled the “touches per fumble” into two buckets… before the 2007 rule change and afterward. The other metric was showed “touches per fumble” per year, so you could see each year leading up to and then after the 2007 rule change.

I find the per-year stats to be the easier to understand so it is the first I’ll show:

KIGFumblesThis image links to a colleague’s website It’s a small portion of a much larger infographic they have on this. One feature of this additional information is shown at the bottom… Killer Infographics summarizes the effect with additional stats like “increased points per game”. Essentially answering the latent question “sure they fumbled less, but did this result in increased scores/wins?”.

Oddly this exact same infographic is available from the Slate magazine article on this subject, but their version of the above infographic doesn’t appear until page 2 (yea, you gotta click to get to page 2 on Slate). Slate instead leads with the more complicated looking (IMO) infographic comparing (2000-2006) in one side and (2007-2014) on the other, shown at the right. The years are important, because 7 in both so in a perfect world they’d be the same, but the red arrow shows that the Patriots touches-per-fumble before the rule change was average while their touches-per-fumble after was crazy high. Additionally from an infographic design POV the chart Slate lead with has “useless” information on the vertical axis… the heights of the bars means how many other teams had that same statistic (eg the Patriots were one of 4 teams that averaged 42 touches per fumble from 2000-2006). Not really relevant to our interests.



Both infographics were pulled together from Killer Infographics leads with the simpler chart so kudos to them.

However, I would love to see (but do not have time to compile myself) a chart like the first one above that shows ALL the teams INDIVIDUALLY instead of averaged together. For one, there may be a few more teams hiding their own “deflate-gate” in there. Additionally, the average touches per fumble seem to be slowly increasing, with the average being noticeably higher in 2014 than in 2006. This might be a natural consequence of  teams being able to use their own balls because of comfort and familiarity or tweaks to the footballs within the allowable range. Or it could be that teams over time have slowly started to adopt their own version of “deflate-gate”.

But it is odd how, right after the rule change, the Patriots fumble rate went from about 40 touches per fumble to about 80 touches per fumble… it’s as if they had plans in place for that rule change. Go Hawks.

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