Saturday, December 03, 2005

What are the odds?

You live in a house that sits below sea level. The only thing that keeps the ocean and the callous whims of nature from rolling into your living room is a levee. A man-made ridge of earthen materials constructed to keep your life and your property safe and secure.

Now we all know that nothing is perfect, and I think we would all agree that nothing lasts forever. But if you’re going to live and work in the shadow of that levee, you probably want to know that every reasonable step has been taken to minimize the risk. You want the probability of levee failure to be low, very low.

What are the odds?

* If your house is in a densely populated area of the Netherlands, the odds of failure are 10,000 to one.

* If your house is in New Orleans, the odds of failure are 100 to one. (To be technically precise, there is a 1% annual chance of levee failure.) This same design standard applies to most federal flood control projects.

Think about it this way: As the average lifespan approaches 100, the odds are that almost every person in New Orleans will experience a catastrophic event in their lifetime. For a Dutch citizen, only once in 100 lifetimes.

Compare this to commercial air travel. According to, the odds of being on an airline flight which results in at least one fatality is about 1 in 186,000 if you’re flying on an airline that is among those with the worst safety records. That’s 1 in 186,000. If you live to be 100, you’d have to fly 1,860 times a year before the odds of being on a fatal flight match your chances of seeing a flood disaster in New Orleans.

But better yet, if you fly on one of the leading airlines in safety, your odds improve to 1 in 4,200,000! It’s odds like these that make commercial air travel viable.

So now the question: does the current 100-year standard for flood protection in New Orleans make any sense? Would you invest in a city that will, in all likelihood, flood at least once in your lifetime?

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