Tuesday, September 15, 2009

Please Drive Your Kids to School

The article in Sunday's Times about driving your kids to school has generated a lot of discussion. I just posted a mini-rant in Reader about this, and figured it was worth re-posting here.

As a parent and a computer scientist, to me this comes down to basic probability theory. The idea of the "only 115 abductions a year" stat is to make it sound as though the chances are so low that it's not worth protecting against.

As we all remember from discrete math, though, you don't care about the probability, you care about the expected value. As a parent, the cost of losing a child is, for all practical purposes, infinite. So any "lose my child" event with non-zero probability becomes worth preventing against. The cost of driving a kid to school each day is astonishingly low; there's no point in NOT doing it.

The author is basically appealling to the sentiment of "why aren't things the same as when I was a I kid?" To them I say: the world changes, get over yourself.

This is not meant to be an argument for protecting kids against all possible dangers, but driving your kids to school is pretty much a no brainer. It's right up there with "should I buy my kid a car seat or not?"

By the way, most states these days have much stricter car seat and seat belt laws for children than when we were kids. My kids will never know the joy of bouncing around, unrestrained, in the way back of an '85 Oldsmobile wagon. That's life.


Sam said...

How many kids are injuring in car accidents each year? http://www.kidsandcars.org/ reports 687 incidents last year resulting in 204 deaths. I'm also curious about your intimation that the world has changed. Have child abductions increased, or are there the same or fewer than in years past?

There is a large societal cost to driving children to school rather than have them taking their bike, walking, or even taking the bus. It promotes an unhealthy, insular community that feels that safety is linked with literally isolating yourself in a large, noisy, fuel-consuming box.

Andy said...

Once you assign infinite cost to something, you can't reasonably use EV analysis.

8000 children per year die in car accidents. Cost of child loss is infinite, so no putting your kids in the car.

3 school shooting deaths in the US this year. Cost of child loss is infinite, so better home school.

You end up with your child in a padded room for their own safety.

You also ignore the costs of sheltering your child, and not letting them experience life out from under the umbrella of mommy and daddy.

I also say it is not the world changing, rather it is the media coverage and the ease of dispersal that has changed. What was once a local news story that only ran in the local newspaper is now propagated all over the internet.

Also, the violent crime rate in the US is lower now than it was in the 70s and 80s, when you and I walked to school without anybody abducting us.

Equating walking to school with not wearing a seatbelt is fairly ridiculous, and can only happen because of your "infinite cost" scenario.

Unknown said...

If the opportunity cost of something approaches infinity, then any finite probability behavior achieves too high an expectation value (risk). Better get rid of that play structure in the back yard!

Number of children killed in playground accidents (2008): 15

Number of children seriously injured (paralysis/brain damage/spinal injury) (2008):78

Perhaps the best statement is, "Statistics lie on both sides of the arguement"

Unknown said...

I agree 100%. It is the parents responsibility to take the utmost care of their children.