Bad charts can happen to good people
Doing legwork, doing justice

Highway Safety Agency goes rogue

A reader sends me to Adam Obeng, who did the dirty work deconstructing a set of charts by the U.S. National Highway Traffic Safety Administration on his blog. Here's an example of these charts:


Aside from the sneaker chart, they concocted a pop stick, a pencil, a tower of Hanoi, etc. These objects are ones I think should be evaluated as art. Adam gamely tells us that the proportions are totally off, and they are both internally and externally inconsitent.


I'll add two small points to Adam's post.

First, these charts pass my self-sufficiency test, that is to say, they did not print the entire data set (just one number here) on the page. Alas, given the distortion identified by Adam, not printing the data means everyone is free to create their own data. Herein lies the problem: there is an argument for allowing a small degree of distortion in exchange for "beauty" but these charts without any data have gone too far.

Second, see Adam's last point (the footnote). The original data is something quite convoluted: “3 out of 4 kids are not as secure in the car as they should be because their car seats are not being used correctly.” (How would they know this, I wonder.) This is a statistic about kids while the picture shows a statistic about their parents (or drivers).




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You asked: "How would they know this, I wonder." I understand that the police stops cars with child seats during awareness campaigns and check whether the seats are correctly installed.

I couldn't understand the first such ad, even though I see graphs everywhere. It took me 2-3 viewings to understand what they were suggesting a chart and then quite some time to understand it. It would have been better to have pictures of four kids in child seats.

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