CultureMap Claims I-45 Is The Second Most Dangerous Highway in the US. They are Wrong.
by Andrew Chalk
CultureMap is at its best when it regurgitates press releases from the restaurant trade (and they hire accordingly). When they get into numbers, things fail badly. A case in point is the current front-page story that "I-45 is the second most dangerous highway in the US". This claim is based on the number of fatalities per mile.
Unfortunately, CultureMap does not control for the number of cars on each highway and that, as any graduate of statistics 101 will tell them, makes their results worthless. A counterexample proves the point: Suppose, hypothetically, there are absolutely no vehicles on I-45. You then drive onto it to begin a journey. Unknown to anyone, an invincible Gobbling Monster comes down from outer space and positions itself on I-45, waiting for cars to appear. The Gobbling Monster is so deadly that it consumes cars in one gulp. Vehicle, passengers, even the cupholders.
When it gobbles your vehicle (with just you in it) the number of fatalities goes from zero to one in the CultureMap dataset. A number of fatalities so low that I-45 does not figure as a dangerous highway in the CultureMap dataset. However, the death rate for users is 100%, clearly making it ”the most dangerous highway in America”.
The error, not controlling for the number of cars on each highway, is a fundamental flaw. It means the results cited by CultureMap are worthless and should be ignored.
Culturemap apparently got their results from a press release by someone else and reproduced it, "monkey-see, monkey-do" fashion. The writer and editor not only did not understand statistics well enough to realise that this press release was best consigned to the round file, but they did not understand statistics well enough to know what they did not know! Culturemap has committed numerical howlers before (such as claiming that the Bass Family of Fort Worth were ‘millionaires’) but this latest one is the worst.