In 40 years 13 out of every 10 US citizens will not have landlines. The kind of reasoning that leads to this conclusion also supported the recent claim that in 40 years 10 out of 10 Americans will be obese. As the Numbers Guy in the Wall Street Journal points out:
The phone forecast is impossible, of course, but it’s arguably no less solidly grounded than the obesity forecast. The weight projection uses three data points spread out over nearly three decades to estimate a linear trend — then brazenly draws that line into the future.
Human beings have real deficits in reasoning about probability, and that can include people giving medical advice, but you don’t really expect it to show up in a scientific journal, even an online journal like Obesity (link corrected thanks to Noumena in comments), where it was published. Certainly, at least not one backed by the highly respected Nature Publishing Group.
The recent study was intended by lead author Youfa Wang “to send a message” to public-health officials, he says. Dr. Wang, associate professor of international health and epidemiology at Johns Hopkins University, adds that there is no conflict between this goal and the standards of scientific inquiry. He notes the scientific pedigree of his co-authors, who include Hopkins colleagues, and researchers at the University of Pennsylvania and at the federal Agency for Healthcare Research and Quality.
And the response when confronted with the problem?
“This study isn’t designed to predict what the future actual situation will be,” Dr. Wang says. “We just say, if you take these assumptions, this is what the future may be.”
Richard Bergman and David Allison, editor and associate editor, respectively, of Obesity, wrote in an email: “Each scientific paper is hoped to be an ever closer approximation to the best possible answer to a question than was the work that had gone before. We believe Dr. Wang’s paper fulfills that spirit.”
On the fact of it, I’d say the paper deserves a C or a D and a good scolding that centers around not presenting propaganda as though it were truth. And the editors? Well, I just hope they are not the sort that grumble at cocktail parties about how post-modernism is the curse of academia.
Is that too harsh? What do you think?
(And thanks to Tara Parker-Pope’s article for the link to the Numbers Guy.)