Living the (micro) life

One way to quantify risk

US scientist Ronald A Howard first introduced the concept of ‘micromorts’ – a unit of risk measuring a one-in-a-million probability of death. This allows us to compare the risk of day-to-day events.

For example, in the medical world, going under anaesthesia for a non-emergency operation exposes you to an average of ten micromorts. In the UK, giving birth (all births combined) is worth 120 micromorts; a Caesarean section increases this to 170. Sky-diving, rock-climbing and hang-gliding come in at ten micromorts or lower. Calculations suggest each mission flown by a member of Bomber Command in World War II carried 27,000 micromorts – a 2.7 per cent chance of death.

About this resource

This resource was first published in ‘Number Crunching’ in June 2013.

Statistics and maths, Medicine
Number Crunching
Education levels:
16–19, Continuing professional development