The "Zero-Probability Fallacy" Fallacy
By Bryan Caplan
Lenore Skenazy’s Free-Range Kids has 58 5-star reviews on Amazon – and only one 1-star review. But Olga, the book’s lone detractor, makes a striking argument: The real innumerates are not paranoid parents, but people like me and Skenazy who mock them.
According to Lenore, if the chance of your child being abducted and
tortured to death by a stranger is only 1 in 610,000, then you should
simply act as if the real number is zero. Using this type of logic, I
should discontinue wearing my seatbelt every time I get in the car.
It’s uncool. Paranoid. The chance of dying in a car accident is only 1
in 100 over my lifetime, so, it might as well be nothing…
Well, 115 children in the US are abducted by strangers, sexually
assualted and murdered every year. 115 yearly. That isn’t an urban
myth. It isn’t a horror film. It isn’t a Stephen King novel. It’s 4
classrooms full of children.
There is a difference between “rare” and “non-existent”. In the
face of any kind of preventable risk, a parent has a responsibility to
work to prevent the event, regardless of the odds against it ever
My reply to Olga: Yes, there is a difference between “rare” and “non-existent.” Taking precautions against a non-existent danger is silly; taking precautions against a rare danger might be wise. So far, we agree. My objection: All parents, including you, frequently fail to try to prevent risks. Why? Because after you reduce a risk – for example, by buckling your child’s seat-belt, a risk still remains. Buckled children still get injured. And that risk is also preventable! You could make your child wear a helmet in the car to further reduce the risk of head injury. You could make him wear thick clothing – or a face mask – to protect him from shattering glass.
Or you could just stay home, brick up your windows, and make your kid wear a bullet-proof vest.
I bet even Olga would admit that these precautions are absurd. But what makes them so? Simple: They only slightly increase safety at a large cost. Which is precisely Skenazy’s objection to Today’s Typical Parents’ effort to prevent child abduction. She doesn’t advocate zero precautions. She explicitly tells her kids not to “go off with strangers.” But she uses probabilities to convince readers that the additional precautions parents take – like keeping nine-year-olds under continuous observation – are absurd.
Of course, parents’ risk-aversion varies. But it’s still fair to ask them do comparative risk analysis. If you’re willing to drive your kids to the mall, and car travel is forty times more lethal per minute at unsupervised mall loitering, then why will you allow the former but not the latter?
Olga ends with a challenge to Skenazy: “Who are you to claim that the antidote to ‘unrealistic fear’ is to dishonestly give your children a false sense of security?” But this just raises a deeper question: What is a “true sense of security”? If it requires absolute safety, then no one could ever justifiably feel secure. That’s ridiculous. If you can’t feel secure – and teach your children to feel secure – about 1-in-610,000 nightmare scenarios – the problem isn’t the world. It’s you.