RISK 101

We all face risks every day. But it’s often hard to tell when a risk is truly dangerous and when it’s trivial. Fortunately, some smart people have created ways to measure and compare risks that are pretty easy to understand. Read on to find out more.






Everybody knows that skydiving is riskier than a walk in the park. But is skydiving riskier than texting while driving? Or taking heroin? The concept of the micromort, invented by renowned decision analyst Ronald A. Howard, allows us compare any potentially lethal risk. So what is a micromort? It is a one in a million chance of sudden death. And everything we do comes with a micromort attached.


We all sense that some habits (like exercise) might help us live longer while others (like smoking) may cut our lives short. But it’s hard to care because the consequence is far in the future. The concept of the microlife, invented by renowned Cambridge University professor David Spiegelhalter, provides a way to bring the results of our habits into the present. So what is a microlife? It turns out that on average, once we reach adulthood, we have about 60 more years to live – roughly a million half hours. A microlife is one of those half-hours. When we indulge in a habit we either add half-hours to our lifespan or take them away. Seen this way, a brief jog (adds one microlife) looks great while a cigarette (subtracts half a microlife) might not seem so enticing. The microlife concept can also prevent needless hysteria. For example, as you might guess, a bacon habit will shorten your life (minus one microlife per serving) but as the microlife measurement makes clear, one bacon sandwich won’t kill you.


The word “radiation” can conjure varied images and emotions. It might bring to mind the cloud of radiation caused by an atomic bomb (terrifying) or the radiation one receives from a medical X-ray (not so terrifying). It’s well known that the dose from an atomic bomb can be deadly. But at what lower level is radiation completely safe? Science has yet to fully answer that question, but it has produced a unit of measure that roughly defines health risks. The unit is called a sievert. One sievert is high dose – enough to cause acute radiation poisoning. A thousandth of a sievert - a millisievert - is the amount of natural background radiation we can all expect to be exposed to in one year. In between are many radiation sources from cosmic rays to medical scans to nuclear power plant melt downs. Eating a banana will give you a dose of .00001 millisieverts, and so will going through an airport scanner. Is that dose completely risk free? Common sense suggests it probably is. But as for the science… the jury is still out. (Video courtesy of Andrew Maynard at the Risk Innovation Lab, Arizona State University)

Cultural Cognition

For some of the biggest societal issues – climate change, gun control, terrorism – large swaths of the public see the risk (or lack of risk) in wildly divergent different ways. Why do our risk perceptions vary so much? Some blame the media. Some blame an inadequate education system. But Yale University researcher Dan Kahan is a proponent of a different explanation – the idea that our personal risk perceptions aren’t primarily guided by facts at all, but by our cultural style – what some call our “tribe.”

Beyond Risk 101

The risk experts who participate in this project provide first rate online resources where you can find out more.

Why don't we all agree about the risks of global warming? Are some people just stupid?

Cultural Cognition. This theory contends that our ideas (cognition) are determined by the beliefs of the cultural group we’re in. To (over)simplify, we tend to hold the beliefs and identity of our tribe.

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Understanding Uncertainty

Top UK risk expert Sir David Spiegelhalter has a constantly updated website packed with info, insights and infographics that explain how to quantify risks and rewards.

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Risk Bites

Director of the Arizona Risk Innovation Lab Andrew Maynard has a YouTube channel filled with his whimsically animated videos about every risk factor under the sun.

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Extreme Risk Blog

Renowned athlete Will Gadd has an informative blog where he shares hard won secrets about how to survive extreme risk.

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