Freakonomics and the Car Seat Debate:

I'm rapidly becoming addicted to the Freakonomics blog. The latest brouhaha on child safety seats, airbags vs. seat belts, etc., is quite interesting. Levitt argues that the data fails to support the hypothesis that car seats are safer than seat belts for children over the age of 2 years who are involved in an accident. He was criticized by a letter in the New York Times as being "irresponsible and dangerous" for publishing this conclusion and the fear was expressed by the letter-writers that they hope this "misleading article does not cost a child his life."

Also, see Alex Tabarrok's take on the child seat debate, criticizing the subordination of the scientific issue to activist conclusions.

Mike Rappoport sees something similar in legal scholarship, but I think there is one difference--I think that law professors may be more comfortable with intellectual disagreement (having been weaned nursed on the adversary system) and so that in theory there may be more of a check on the potential negative efffect of "activist scholarship" than perhaps for medicine/public health. I have the utmost respect, admiration, and deference to the medical profession, but would I be rocking the boat too much to raise the possibility that those from that world sometimes can be, shall we say, perhaps a bit paternalistic and a bit impatient with those who question their authority? I remember one medical person telling me that the very idea that there could be such thing as "lower-risk tobacco" (such as chewing tobacco vs. cigarettes) was like saying that someone could be "a little pregnant." (I reminded this person that at the very least she had to admit that the second-hand smoke risks associated with chewing tobacco are somewhat lower than for cigarettes.) The idea that Levitt's scientific conclusions from the data on car seats could be "irresponsible and dangerous," as opposed to perhaps "incorrect" or "unsupported," is really sort of a peculiar and unhelpful way to think about what is, after all, a positive empirical question, not a normative question.

Not to mention that the letter's kicker, "We hope that this misleading article does not cost a child his life," completely misconceives the public policy question. Again, I don't know if Levitt is correct. But if he is, then this means there are people who unnecessarily spend money on car seats (say to replace a broken car seat when a kid gets old enough to ride with a seat belt instead), who could otherwise spend that money on something else that benefits their kids' health (food, medicine, doctor's appointments, etc.), or other good things for their kids (books, exercise). In which case, Economics 101 tells us that laws that force people to spend money on unnecessary car seats also have the inevitable effect of leading to childrens' deaths as well. In a world of scarcity there is never a free lunch. Passing laws that forbid people to take car rides of more than 8 hours or prohibit driving over 30 miles an hour or prohibit people from driving small, light fuel-efficient cars might also reduce the number of casualties to chldren. But there are obvious social tradeoffs on safety, economics, and other concerns for each of these policies. The question is which policy is going to result in fewer overall casualties.

There are plenty of situations where what was originally thought to be true turns out later to be incorrect (Russ Roberts reports that 1/3 of medical conclusions turn out to be incorrect), or where efforts to regulate generate unintended consequences and incentives that defeat the regulation or cause unanticipated side-effects. So we gain little, and potentially lose a lot, when we shut down scientific inquiry on the basis that we are concerned that the public may misuse the information that results.

Let me emphasize--I don't know wither Levitt is correct. But conflating statistical analysis with activist demagoguery and inflammatory rhetoric that his research is going to kill kids isn't going to help us figure out the best policy here.