Steven Levitt and Stephen Dubner, in Freakonomics, explain that “car seats” provide barely any protection above and beyond what seatbelts would provide. This in itself was not a well-qualified statement (what size of child? lap belts only? what seatbelt-induced injuries, if any?), but the sequel made matters worse.

  • Supercalifreakonomicsexpialidocious, p. 151, states that “car seats” must “be anchored in place by the car’s existing seatbelt.” Have they even looked at a car built in the last eight years? Lower anchors and top tethers are required to be installed in many rear seating positions by U.S. and Canadian spec. These LATCH anchors allow you to attach a child restraint directly to the frame. You may instead use seatbelts, but there is no reason to do so unless (a) you don’t know LATCH exists or (b) your child restraint or car is so old it doesn’t have LATCH.

  • I was surprised to see a mention of incorrect installation in the book, but the authors still have not that as a variable in the data. Remember: Car seats are the least usable consumer product. A reasonable prediction for an economic scientist would hold that child restraints are so hard to install properly that most of them won’t be. If so, as attested data shows, then injuries and deaths can be traced to incorrect installation. A true comparison would be known-well-installed vs. known-poorly-installed child restraints.

    Levitt and Dubner should be looking at figures from Australia, a safety-obsessed nation with seriously rigorous specs for child restraints. (New Zealand standards are functionally equivalent.) Rear-facing infant carriers, for example, may use a foot that anchors them to the car floor to reduce deflection.

  • I would discourage the use of “car seats” as a generic term. I know that’s what ordinary people use and the Freakonomics empire is a populist one. But “car seat” invariably conjures an image of a booster seat. “Child restraint” is the hardware-neutral term. I would also encourage being specific: Rear-facing infant carrier? Convertible car seat? (Facing which direction?) Booster seat?

  • Several auto manufacturers have addressed the problem of designing seats compatible with child bodies. It isn’t hard to buy a wagon or SUV with a built-in child restraint.

The Freako dudes have really been dining out on their deliciously contrarian findings on child restraints. It’s almost part of their mystique by now: You may think you know all there is to know about car seats, but step aside and let the experts tell you what’s really happening. But what Levitt and Dubner write just is not accurate and specific enough.

The foregoing posting appeared on Joe Clark’s personal Weblog on 2010.03.29 14:02. This presentation was designed for printing and omits components that make sense only onscreen. (If you are seeing this on a screen, then the page stylesheet was not loaded or not loaded properly.) The permanent link is:

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