Earthquakes present a stark contradiction: we know how often they are likely to occur but we still can’t predict when they will strike. To be precise, earthquakes follow a ‘Power-Law Distribution’: that is to say earthquakes that kill 100 people occur about 10 times more often that ones that kill 1000 people and 100 times more often than ones that kill 10 000 people. We can therefore say with confidence that disasters of the scale of Haiti are very rare indeed.
Other examples of unlikely events that have come to pass with tragic consequences include:
- Shortly before the Piper Alpha disaster it was calculated by the company that such an event was only likely to occur once every 10 000 years; and
- After the Selby rail crash, the Health and Safety Executive calculated that such crashes should occur only once every 350 years.
At a more mundane level a similar process is happening day-to-day with organisations being surprised by events that are perceived as being vanishingly improbable. We cannot effectively prepare for all of these possible disruptions: rather, we must keep an open mind and be prepared for the unexpected.