Steve Levitt continues his reputation for counter-intuitive economics with a new working paper (which he tantalisingly alluded to in Freakonomics) arguing that child safety seats don’t make kids safer.
Evidence that Seat Belts are as Effective as Child Safety Seats in Preventing Death for Children Aged Two and Up by Steven D. Levitt
Over the last thirty years, the use of child safety seats in motor vehicles has increased dramatically, fueled by well publicized information campaigns and legal mandates. In spite of this movement, there is relatively little empirical evidence regarding the efficacy of child safety seats relative to the much cheaper alternative of traditional seat belts. Using data from the Fatality Analysis Reporting System (FARS) on all fatal crashes in the United States from 1975-2003, I find that child safety seats, in actual practice, are no better than seat belts at reducing fatalities among children aged 2-6. This result is robust to a wide range of sensitivity analyses, including controlling for sample selection that arises because the FARS data set includes only crashes in which at least one fatality occurs.
Near the end of the paper, he addresses the explanation that probably pops into most people’s minds (especially if you read this engaging little New Yorker column recently):
An obvious question to ask, although one which is beyond the scope of the FARS data, is the extent to which the failure of child safety seats to outperform seat belts is a consequence of child safety seats frequently being improperly installed. … it is worth noting that when I conducted my own crash tests at an independent lab using lap and shoulder belts on dummies corresponding to children aged 3 and 6, the seat belts performed well within the guidelines the federal government has established for child safety seats, and just about as well as the (properly installed) child safety seats that I tested. While far from definitive, the crash tests I conducted suggest that even with proper installation, there may not be clear advantages of car seats over seat belts.
Expect a rapid-response from the multi-million dollar car seat industry.