David Spiegelhalter Quotes

One of the other things we do in the book is talk about radiation... [Y]ou can say exposure to radiation, you can talk in terms of micro-lives or cigarette equivalents. So... a flight to New York, the radiation you get from that is equivalent to smoking a couple of cigarettes, about 1/2 hour of your life... The whole body CT scan... exposing yourself... to possibly an unhealthy dose of radiation... 150 microlives, smoking about 300 cigarettes, about the same as standing about 1 1/2 miles from the Hiroshima explosion. ...[W]hen they advertise these things for a thousand quid, they don't tell you that.

Life-expectancy reduced by 1 year = about 30 minutes off your life expectancy for each day with the habit = 1

There'a a nice thing about 1/2 hour because an adult life expectancy is 55 to 60 years... is actually a million 1/2 hours. A million 1/2 hours is 57 years. So you have got, not all of you... some of you have got a million 1/2 hours to fritter away.

That change in life expectancy is not that gripping in itself. So what we've done in the book, it does seem a rather a strange thing to say... "Over an adult lifetime, about... 50-60 years... take a year off your life." It's like losing roughly 1/50 of your life. It's actually because of... these daily habits... like losing a week every year of your life, the same as losing 1/2 hour off a day. So we could say... that... 2 hours watching television... it's as if it's taking 1/2 hour... off your life. ...You're aging an extra 1/2 hour sitting on your backside watching television ...

Gompertz's observation said that between the ages of 25 and 80, your risk of dying increases by about 9% per year. ...[T]hat means that every eight years your risk of dying doubles, essentially. ...[I]t's going to get you in the end. Mathematics proves it. You can't go on forever, because it's this exponential increase in the risk. Amazing, really powerful. That's why you peg out in the end. It's going to get you.

So we've been trying to think of another metaphor... and the one we caught hold of is... speed of aging. So it's turning these numbers, rather bold numbers quite difficult to understand, into stories, and the story we've got is, "Getting older quicker" or "Aging Slower"...

These s that epidemiologists report, as Michael has so ably shown, tend to get... badly reported in the newspapers. So this... in the ... "Less Meat, More Veg is the Secret for Longer Life" which... probably could well be the case, but the way they report it... They said that if we cut down the amount of red meat... 10% of all deaths would be avoided. ...So 10% of us will live forever eating nuts. This is not true. ...[T]hey're talking about relative risk, but they don't understand.

When epidemiologists... do studies, when they follow lots of people for years, they measure the effects of various habits, in terms of s. This is what it does to your hazard every year. So if you have a daily sausage or a bacon sandwich, this goes up by about 10%, a fixed amount... as your... annual risk. 10% increase in your annual risk of death, of not making it to your next birthday.

This was discovered by Gompertz in 1825. There's something about our bodies, the way that we age, that means that every year our chance of dying increases by the same amount, 9%.

This is called a hazard curve. ...This is the chance of dying before your next birthday, on average. ...[I]t's... on a , so 10%... (1 in 10) 83 year olds will not see 84... 1 in 100 people like me [age 59] will not see their next birthday. 1 in 1,000 thirty-two year olds, and 1 in 10,000 7 year olds... and there is a... lump, sadly jumping up at 17, as you can imagine... boys... a risk-taking lump, but if you ignore that lump... it's a... straight line between... 7 and 90.

So it's a different sort of risk. These are chronic risks. ...[T]hings that... if you carry on with them, are likely to shorten your life. So how can we express these... [T]hese are the ones that newspapers tend to get terribly wrong.

So... in the book we make all these comparisons... That's acute timing risk, things that are going to kill you on the spot. ...What about the other sort of risks? ...You can have your spam ...[T]hat is not going to kill you on the spot. Well, it might. ...You might choke on...[it]... but it's... unlikely...

The point is... that you can make these comparisons quite easy... is... 8 [micromorts], running a marathon is... 7, ... 5, 's going to be 400...

If you go to the English Parachuting Association web site... you find this lovely Excel spreadsheet which has got all the deaths... [F]or the last 20 years, 4.6 million jumps, 48 deaths... or 10 in a million. On average, with going up in a plane... I thought there's around 7 or 10 in a million chances of me dying. There's 50 million people in England and Wales... Every day 50 of them have accidental or violent deaths... not to do with their health. So a couple are murdered a day, a few are run over, some people fall off ladders, etc... So that's 1 in a million... Our daily dose of acute risk is a [a 1 in a million chance of dying]. So jumping out of a plane is only about a week's worth. ...[I]n terms of overall mortality... at my age, 59, it's 7,000 micromorts a year in terms of my chances of dying. So an extra 7 or 10 on top of that... [I]t's worthwhile doing... it once....So I did it [parachuted], and I survived.

What we use in the book... are ways which we think might... provide gripping narratives, and yet provide a realistic way of communicating small risks...