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What are the odds? Risk and reality

Without chance events and the upending of natural probabilities, drama would be a monotonous montage of commuting, working and TV.

Climbing Everest: risky. Photo/Thinkstock


The concept of MicroMorts was defined by researchers at Stanford University in the 1970s. One MicroMort represents a one-in-a-million chance of dying. We can measure the death risks of different activities based on their estimated number of MicroMorts. For example, rock-climbing has a MicroMort rating of 3 for each climb. This means that every time you go climbing, you add three chances in one million of dying. Below are the MicroMort (MM) estimates of some common and not-so-common events:

Smoking 1.4 cigarettes: 1 MM.
Drinking half a litre of wine: 1 MM.
Giving birth: 120 MM per birth (UK 2010).
Giving birth by caesarian section: 170 MM per birth (UK 2010).
Anaesthesia for a non-emergency operation: 10 MM per operation (UK 2010).
Coronary artery bypass graft: 16,000 MM per operation (UK 2008).
Scuba diving: 5 MM per dive (UK 1998-2009).
Hang-gliding: 8 MM per jump (UK 1998-2009).
Rock-climbing: 3 MM per climb (UK 1998-2009).
Skydiving: 10 MM per jump (UK 1998-2009).
Running a marathon: 7 MM per run (US 1975-2004).
Riding 96km (60 miles) on a motorbike: 10 MM (UK).
Driving 4,000km (2,500 miles) in a car: 10 MM (UK).
Serving in the UK armed forces in Afghanistan: 47 MM (May-Oct 2009).
Climbing Mount Everest: 12,000 MM per climb (1990-2006).
Flying in Bomber Command in WW2: 27,000 MM per mission.

Source: The Norm Chronicles: Stories and numbers about danger, by Michael Blastland and David Spiegelhalter, Profile/Allen & Unwin.

For more on risk, plus ways to improve your chances of living a longer, healthier life, read this week's Listener cover story: Beating the oddsSubscriber contentIcon definitionSubscriber content

The banal reality of real-world statistics is bad news for journalists and death for drama. “The media's interested in very unusual, rare events,” says UK journalist Michael Blastland. “You don't want to hear ‘No child hurt on the way to school today’ – it's not a story. Several million children unhurt on the way to school today is still not a story. One child catastrophically run down by a bus is.” He says there is some evidence in the US that people think deaths from tornadoes were more frequent than those from asthma. It’s the other way round by a factor of zeroes, and a large part of that is that deaths from asthma do not feature on the news.

Without unlikely coincidence and the upending of natural probabilities, drama would be a monotonous montage of commuting, working and watching TV.

To illustrate how uneventful by comparison everyday life is, watch the period skit The Man Who Had A Cough And It's Just A Cough And He's Fine, by British comedians Mitchell and Webb.

http://www.youtube.com/watch?v=8vNJ5Krj7SQ

Or there’s The Day Today sketch in which Steve Coogan’s pool supervisor, who is criticised for a drowning, points out in dreary monotony all the other years in which absolutely nothing happened.

http://www.youtube.com/watch?v=ob1rYlCpOnM