Monday, July 19, 2010

FREAKONOMICS Fallacy: An Economist or a Pediatrician - Who Would You Trust To Keep Your Child Safe?

Economists vs Pediatricians
Who is really looking out for your child's safety?

Unfortunately, many parents have mistakenly put their trust in the economists Steven Levitt & Stephen Dubner, co-authors of the popular book Freakonomics, rather than following the advice of pediatricians and the medical community when it comes to protecting their children in the car.  In 2005 the Freakonomics authors wrote an article in the NYTimes Magazine entitled "The Seat-Belt Solutionwhich came to the sensational conclusion that "there is no evidence that car seats do a better job than seat belts in saving the lives of children older than 2." But fatalities are just the tip of the iceberg; for every death there are 19 injuries requiring hospitalization (some leading to permanent disability) and 300 requiring medical attention.

While Dubner & Levitt have "softened" their stance over the past 5 years to say that "car seats are a little better..." than seat belts and advised parents "don't throw out the car seats" The Car Seat Ladies feel like the damage has been done - and we want to try and undo it by providing you with the whole story. More people heard and remember the sensational message than Freakonomics' weak efforts to bring their message more in line with what we know to be best practice. Therefore, we at The Car Seat Lady want to provide you with the evidence so that you can come to your own conclusions and make the best decisions regarding your child's safety. As an interesting side note, both Dubner & Levitt admit to using car seats and boosters for their own children beyond the age of 2; they are willing to endanger the lives of other people's children to sell their books, but aren't willing to make their own children be the guinea pigs for their own misguided hypothesis.

Dr Dennis Durbin & Dr Flaura Winston are pediatricians at the Children's Hospital of Philadelphia and co-principal investigators for the Partners for Child Passenger Safety study, which is the largest study ever done of children in crashes. Data from this ongoing study has led to the publication of dozens of papers in some of the most highly regarded peer-reviewed medical journals including JAMA, Pediatrics, Archives of Pediatrics, Journal of Trauma, and Injury Prevention. 

Drs Durbin & Winston wrote a letter to the editor in response to the 2005 NYTimes article.   
  • "As pediatricians, scientists and leaders of the world's largest study on children in crashes, we think that overinterpretation of findings from a single source of data led Stephen J. Dubner and Steven D. Levitt (July 10) to claim that child safety seats are no more effective than seat belts for 2- to 6-year-olds. They examined children in fatal crashes (about 1,200 per year) while ignoring the equally informative data on those in nonfatal crashes (450,000 per year). Our research, which includes over 25,000 in-depth interviews and over 800 crash investigations, consistently shows that child safety seats and booster seats significantly lower the risk of serious injury compared to seat belts alone. Their conclusions stand in stark contrast to the existing body of scientific data that support current child restraint recommendations, and are, in our opinion, irresponsible and dangerous.  Learn the facts at We hope that this misleading article does not cost a child his life."
Drs Durbin & Winston followed up this letter with an study published in the June 2006 issue of the Archives of Pediatrics & Adolescent Medicine. This study was designed in direct response to Freakonomics' conclusion that seat belts are equally effective as car seats/boosters at preventing death for kids 2-6 years of age.  Drs Durbin & Winston's study found that children who were using child restraints were 28 percent less likely to be killed in a crash than children who were wearing seat belts alone - or as Dr. Durbin explained "for every 100 children who were killed in a crash wearing only a seatbelt, 28 of them would have survived if they'd been in a car seat or booster seat."  

In August 2008 Dubner & Levitt published their study concluding that seat belts are equally effective as child restraints for kids 2-6 in the journal Economic Inquiry.  A quick survey of the archives of this journal uncovers such scientifically rigorous and groundbreaking studies as "Secret Santa Reveals the Secret Side of Giving" and "The Influence of Social Forces: Evidence from the Behavior of Football Referees".

The data refuting the Freakonomics conclusion keeps coming in.  A 2009 article from the Partners for Child Passenger Safety study published in Pediatrics showed that 4-8 year olds using boosters seats were 55% less likely to be injured in a crash than 4-8 year olds wearing seat belts alone - or said another way, for every 100 children injured in a crash wearing only a seat belt, 55 of them would have been injury-free if they'd been in a booster seat. 

The Car Seat Lady feels that car seats (with a 5 point harness) are the best protection for kids until they are at least 4 years old AND at least 40 pounds (but with many seats offering the option of using the 5-point harness beyond 40 pounds we are in full support of this) - and boosters are the best protection for school age children until the vehicle's seat belt fits them properly without the booster (i.e. when they can pass the 5-step test). 


  1. Turns out, I would trust an economist. If their analysis is sound, why wouldn't you?

    Fundamentally, Levitt's methodology is the deciding factor. All of the medical studies suffer from the same flaws: using indirect data sources, such as self-reports.

    The benefit of Levitt's study is that it looks at car seats as they are ACTUALLY used in "the wild", from on-the-scene data collection, no post-hoc problems or memories to cloud the results.

    Given the title and subject of your blog, I expect you to be skeptical, however, that doesn't excuse your generous use of red herring fallacies of every type rather than addressing the actual argument.

    Given the fact that most car seats are installed improperly, and the data that demonstrates that seat belts work almost as well for kids over 2 years old, the conclusion is clear: no additional equipment = no chance of installing it improperly. In addition, people could keep their hard earned money in their pockets instead of buying an extra device for their car.

    The best part is: these data include instances where car seats would have been installed improperly, AND the instances where the seat belt would have been worn incorrectly!

    Regarding the fact that Levitt and Dubner both admit that they use car seats...of course they do, it's the law.

    The question is, given the fact that noone has actually refuted Levitt's results, even though he has offered the data to others to analyze (and has now analyzed HUGE national sets of data), why are people so hostile? If it is correct, we should be happy that we have been enlightened. We can save our kids, and our money.

  2. I wonder if those economists were comparing the safety of a seat belt with a Forward Facing or a Rear Facing seat.
    Because research shows kids under 2 are 75 percent less likely to suffer serious or fatal injuries if they're in rear-facing seats.
    What do they data to say to that?