Lessons from the long tail of improbable disaster

By Steven Pearlstein,
WashPost
Tuesday, March 15, 9:02 PM

If it seems that the frequency and size of calamities have been picking up in recent years, it’s only because they probably have.

In just the past decade, we’ve had the attacks of Sept. 11, the tsunami in the Indian Ocean, Hurricane Katrina, the global financial crisis, a global flu pandemic, the earthquake in Haiti, the oil spill in the Gulf of Mexico, and devastating floods in Australia and New Zealand. Now, Japan has been hit with a triple whammy of earthquake, tsunami and nuclear crisis.

What all of these have in common is that they are all low-probability, high-impact events — the “long-tail” phenomenon, to use the jargon of risk modelers, referring to the far ends of the traditional bell curve of probabilities, or “black swans,” to use the metaphor popularized by former Wall Street trader Nassim Nicholas Taleb.

Such calamitous events have been a regular part of the human experience since Noah and the flood, some of them natural, others manmade. In spite of that, however, we continue to underestimate their frequency and severity.

(More here.)