Our grasp of risk, unless it’s accompanied by fear, is generally unreliable. We’re equally poor at acting rationally when it comes to gambling for gain. More often than not we act in stupid denial of elementary probability theory.
For example, crowds flocked to Romford last week to buy tickets for the National Lottery. It’s the luckiest town in the UK in terms of lottery winners, and the ‘rollover’ reached a record high before this weekend’s draw. Morons.
And last week the Government’s chief medical officer issued new advice on alcohol consumption. Men may no longer drink more than women, none of us must drink more than 14 units a week (seven glasses of wine), the slight benefits of alcohol are confined to women over 55 and all of us must abstain from alcohol on several days each week. There is no level of alcohol consumption that is safe.
Denial, predictably, was immediate. A succession of red-faced and unwell-looking men and women popped up to say they’d been drinking heavily for years and it hadn’t done them harm.
Tweets to BBC News arrived thick and fast:
‘How can there be a recommended level of consumption if there’s no level that’s safe?’
‘How can we believe the Government if their advice keeps changing?’
Frankly, these reactions are as stupid and annoying as when you ask someone for an average and you get the answer ‘Well, sometimes there are as few as ten and sometimes as many as a hundred.’ There’s no excuse for mathematical innumeracy on this kind of scale.
Is there anything more infuriating and tedious than the old lady who smoked thirty a day, drank half a pint of vodka before breakfast and lived to be a hundred. We’ve all got these improbable survivors lurking somewhere in our family trees. And we all trot them out when someone tells us that smoking and drinking are bad for us.
Doesn’t anyone understand a probability curve?
It’s absolutely clear what the UK’s Chief Medical Officer is telling us. True, it might not be the final word on the matter; all scientific research is provisional. But if you can be bothered to listen or read more carefully you’ll see that the idea of a ‘safe level’ is defined as a lower than 1% risk that you will die as a result of alcohol consumption.
Even so, how does this compare with the risks of other voluntary activities, such as driving, smoking, unsafe sex, or mountaineering? How can we compare one such risk with another? Who can ‘feel’ or ‘fear’ a 1% risk? And how do we go about balancing risk and pleasure? Mathematics might help us to answer the first question, but the second just isn’t amenable to quantification. It’s a personal judegement, whether foolish or wise.
For reference, 150 people, on average, are killed annually by falling coconuts. This represents a lifetime risk of about 1 in 27,000. But it’s a risk that’s easily averted.
Here are some other risks (as published in 2007 by the New York Times):
|Risk||Annual Deaths||Lifetime risk|
|Heart disease||652,486||1 in 5|
|Cancer||553,888||1 in 7|
|Stroke||150,074||1 in 24|
|Hospital infections||99,000||1 in 38|
|Flu||59,664||1 in 63|
|Car accidents||44,757||1 in 84|
|Suicide||31,484||1 in 119|
|Accidental poisoning||19,456||1 in 193|
|MRSA (resistant bacteria)||19,000||1 in 197|
|Falls||17,229||1 in 218|
|Drowning||3,306||1 in 1,134|
|Bike accident||762||1 in 4,919|
|Air/space accident||742||1 in 5,051|
|Excessive cold||620||1 in 6,045|
|Sun/heat exposure||273||1 in 13,729|
|Shark attack||62||1 in 60,453|
|Lightning||47||1 in 79, 746|
|Train crash||24||1 in 156,169|
|Fireworks||11||1 in 340,733|
So, drinking more than fourteen units of alcohol a week means that you’re slightly more likely to die in a car accident than as a result of alcohol consumption. Does that help? Driving and drinking (though never at the same time) are both pleasures that most of us wouldn’t entirely forego.
“Drinking any level of alcohol regularly carries a health risk for anyone, but if men and women limit their intake to no more than 14 units a week it keeps the risk of illness like cancer and liver disease low,” said Sally Davies, the Chief Medical Officer for England.
Liverpool University’s Professor Matt Field said the advice will help shape people’s choices and added that risk is involved in many of our daily activities. “Any amount of alcohol consumption carries some risk,” the Professor of Addiction said. “However, it is important to bear in mind that most activities that people undertake on a daily basis – e.g. driving to work – carry some risk, and people need to make informed choices about the level of risk that they are prepared to accept.”
It seems obvious to me that alcohol is bad for you. I’ve given it up for January, and after ten days I already feel the benefit – more energy, better sleep, slight weight loss, and so on. I’m not a heavy drinker (I’ve probably averaged about 21 units a week over the last year), but, on balance, I’ll accept the risk in return for the pleasure of a glass or two of a good red wine. I look forward to February.