Wow. I kind of had the feeling the new book Superfreakonomics was going to be weak, but I didn’t expect it to look as rough as the preview currently coming. I enjoyed Freakonomics – it was about doing research, finding results, questioning conclusions, and it had the feel of how research is conducted. The glaring problem with the organizing principle: “People responds to incentives, and you can tell what incentives are because they are what motivates people to do things” was usually glossed over, and you could look at the times when it is invoked with a sense of quirky amusement, like picturing a kid with a bucket on his head running in a circle thinking he is flying.
What I really want to point out is Ezra Klein’s takedown of the opening chapter. Ezra Klein is a health care wonk/reporter/blogger, and he swept-the-leg out of a shoddy econometrics argument by someone who won a Clark Medal for doing econometrics.
The next few pages purport to prove that drunk walking is eight times more dangerous than drunk driving. Here’s how they do it: Surveys show that one out of every 140 miles driven is driven drunk. “There are some 237 million Americans sixteen and older; all told, that’s 43 billion miles walked each year by people of driving age. If we assume that 1 out of every 140 of those miles are walked drunk — the same proportion of miles that are driven drunk — then 307 million miles are walked drunk each year.”
“If we assume.”
But why should we assume that? As the initial example demonstrates, a lot of people walk drunk when they would otherwise drive drunk. That substitution alone suggests that a higher proportion of walking miles are drunk miles. Other people walk, or take transit, when they know they’ll be drinking later. That’s why they’re walking and not driving. That skews the numbers and makes it impossible to simply “assume” parity.
I’m going to refer to this move economists make, where they make some provocative claim based on completely made-up data that doesn’t pass a critical first thought as “Old Custer.”
Why? Did you see the movie The Royal Tenenbaums? In it, Owen Wilson’s writer character Eli from the movie says “Well, everyone knows Custer died at Little Bighorn. What this book presupposes is…maybe he didn’t.”
This Freakeconomics experiment Klein tears to shreds is the exact duplicate of saying “What my argument presupposes is….maybe Old Custer died from walking around drunk.” The argument move “Maybe Custer didn’t die at Little Bighorn” is what is being used for a cutesy, counterintuitive take on drunk driving. It’s really worth noting that if Levitt was giving this argument at a seminar, and Ezra raised his hand and said what he said, the seminar would be over. Killed.