The website makes much of the micromort (a unit of risk measuring a one-in-a-million probability of immediate death) and the microlife (30 minutes of your life expectancy),
- "...many risks we take don’t kill you straight away: think of all the lifestyle frailties we get warned about, such as smoking, drinking, eating badly, not exercising and so on. The microlife aims to make all these chronic risks comparable by showing how much life we lose on average when we’re exposed to them."
- If we expose ourselves to a micromort, we take a 1-in-a-million
chance that our future life will be 0, and hence our life expectancy is
reduced by a millionth. Hence a young adult taking a micromort’s acute
risk is almost exactly exposing themselves to a microlife. An older
person taking the same risk, while still reducing their life-expectancy
by a millionth, is only perhaps losing 15 minutes life-expectancy.
However, acute risks from dangerous activities are not well expressed as
changes in life expectancy, and so different units appear appropriate.
There is one big difference between micromorts and microlives. If you survive your motorbike ride, then your micromort slate is wiped clean and you start the next day with an empty account. But if you smoke all day and live on pork pies, then your microlives accumulate. It’s like a lottery where the tickets you buy each day remain valid for ever - and so your chances of winning increase every day. Except that, in this case, you really don’t want to.
- Is it more reckless to eat a bacon sandwich everyday or to go
skydiving? What's the chance that all children in the same family have
exactly the same birthday? Jim Al-Khalili talks to Professor David
Spiegelhalter about risk, uncertainty and the real odds behind everyday
As one of the world's leading statisticians, he is regularly called upon to help answer questions in high profile inquiries - like the one into the Harold Shipman murders, infant heart surgery at Bristol Royal Infirmary and the PiP breast implant scandal.
Jim finds out more about the Life Scientific of the man who despite winning many awards and his research papers being some of the most cited in his field David Spiegelhalter says he isn't really that good at maths.