STATISTICALLY SPEAKING, MINE'S A PINT

Posted at 12:56

Going back nearly a couple hundred of years to when I was a secondary school scholar, Monday morning was always double maths. I hated Monday mornings for this very reason. We all did, (apart from Roger Burrows who was nothing more than a brain on legs) but fortunately we had a well tested plan. And it almost always worked.

You see, Mr Cosgrove our maths teacher was a fanatical fisherman in his spare time, and so our ‘get out of maths strategy’ was quite simple. Someone would just casually ask him at the start of the lesson... "Did you go fishing at the weekend Sir?” and that was it. Half an hour later, he would still be yacking on; talking about floats, bait and all manner of other tackle I neither knew, nor cared about. But what I did care about was that half of the lesson had gone without me being fazed by fractions, troubled by trigonometry or agitated by algebra.

You see me and maths just didn’t get on back then. It’s probably because I couldn’t really see the point and nobody properly explained it to me. An equation was just a collection of letters and numbers with no practical application that I could ever see. And I could think of no good reason why the angles of a triangle would ever be of any interest or use to anyone. On the odd occasion where a problem was couched in practical terms, it was usually something along the lines of ‘Kevin, Liz, Johnny and Carol have 7 apples, 6 oranges and 12 plums between them, how can they divide them up so each has an equal share, assuming that oranges are worth twice plums, and apples are worth half an orange.’ Even this carried no resonance, because the real world answer is that they would simply give up their fruity bounty to the school bully, else ditch the fruit, and go and buy some Mars bars and Kit Kats instead.

It is perhaps little surprise therefore that despite attending several months of additional night school lessons (a decision not totally divorced from the fact that I got to sit next to an older girl with a penchant for sexy short skirts and lovingly tight tops) I still only managed to scrape a lowly C grade pass at O’ level. And even that exceeded everyone’s expectations.

For the next few years, I carefully avoided anything maths or number related altogether. It wasn’t until I recently began an Open University course, and was forced to study statistics as part of my course that the light bulb switched on. Numbers could be used for something useful after all! And if you played your cards right, they might actually help you to make some money.

While I’ve never quite managed to fully develop a mathematical brain, I have developed an appreciation of some of the uses and abuses of numbers over the years, And it’s the latter which I mainly want to talk about today. You see, if you don’t understand numbers, not only can you miss out on some massive opportunities, but you also leave yourself open to being seriously misinformed and misled. I got to thinking about this last night while watching the government’s latest alcohol awareness campaign advertisements on TV.

I don’t know whether you’ve seen any of these latest advertisements. The earlier ones concerned themselves with the dangers of binge drinking, which it has to be said are numerous. But these latest ones are targeting the regular social drinker - the sort of person who drinks a couple of pints or a couple of glasses of wine in an evening. Needless to say, alas there are dangers in this too, which you haven’t even thought about, and to illustrate this, the ad’s churn out a catalogue of seemingly worrying statistics.

Now before I go any further, I need to make something very clear. I have no specialist knowledge of the real effects of alcohol on the human body. I don’t know exactly what effects it has in either the short term or the long term. But if these recent ad’s are anything to go by, neither does anyone else. Or if they have, they’ve got a lousy way of proving it.

In one of the advertisements, aimed particularly at men, a number of claims are made, backed up by official sounding statistics. I don’t have the time or space here to go into every one, but I’ll just take one of those claims and dissect it. You can do the same thing with any of the ‘scary’ claims made, and then make your own mind up.

Anyway, here’s what the voice over says…“If you’re a man drinking more than two pints of strong lager a day, you’re more than 3 times more likely to get mouth cancer.”

Now on first hearing it, that’s pretty worrying isn’t it? But what does it really mean?

We’ll gloss over the fact that there’s no definition of strong lager given and get straight to the doomsday quantity of lager quoted… “Over 2 pints per day”.

How much over 2 pints do we need to drink to kick the 3 times risk into action? If we drink an extra half pint will that do it? And if it will, might we just as well be hung for a sheep as a lamb and have 6 pints because we’ve already gone over the limit? Is there no difference to the risk between drinking two and a half pints and 10 pints? Surely there must be. And what of the converse situation? If we drink exactly 2 pints a day are we fine? Or do we need to drink one and three quarters? I think we should be told properly.

But moving back one stage, there’s something else that isn’t explained at all. Assuming that we do drink ‘over two pints’ of strong lager, whom are we more than three times as likely to get mouth cancer than? Is it the bloke who drinks nothing at all, or the bloke who drinks one pint a day or the one who drinks exactly two pints? Or is it someone else?

We have no way of knowing. Nothing is defined, nothing is nailed down. It would be bad enough coming from some dodgy double glazing firm, but this is supposed to be our government conveying a very important health message. And it gets even worse too.

Let’s just cut them a bit of slack and assume that on average, men who drink more than two pints of strong lager have a higher incidence of mouth cancer than our lighter drinkers. Does this therefore mean that the lager has led directly to the mouth cancer?

Of course it doesn’t. Heavier drinkers are also more likely to make other lifestyle choices which may not be particularly healthy. People rarely make ‘bad’ choices in isolation. They’re certainly more likely to be smokers, and as anyone who’s ever over-indulged in alcohol will testify, far more likely to eat the sort of greasy, fat laden slop (yes, I speak of you, Mr. Donner Kebab!) which sober folk tend to stay well clear of. It is no coincidence that fast food outlets are usually clustered around pubs.

So if there is this higher incidence of mouth cancer, is it not just as likely that smoking or diet may be to blame, or certainly things that act in tandem with alcohol as contributory factors? Multiple factors like these are notoriously difficult to screen out and weight statistically. They rely on building a detailed, accurate and truthful picture of an individual’s true lifestyle which those individuals are not always willing or able to give.

And now we turn to the stomach churning statistic, ‘three times as likely’… three times! For this purpose, let’s assume that alcohol is totally to blame, 2 pints is the limit, and any more and you’ve trebled your risk of mouth cancer. What does that actually mean? Well, when taken in isolation, not very much. If one in ten people normally get mouth cancer, then trebling your risk to three in ten… 30%, is worrying indeed. On the other hand, if one person in a million normally gets it, then trebling the risk to three in a million isn’t nearly so scary. So the only way we can read anything into this figure is to know the underlying incidence of mouth cancer. Of course, the ads don’t tell us this either.

So I looked it up, and about 9 people in every 100,000 fall victim to oral cancer each year. If we’re assuming that this includes all those people who are drinking beyond their two pints a day, then the underlying rate (for light/none drinkers) must be somewhere around 5 people in every thousand. It therefore follows that heavier drinkers will have an incidence somewhere around the 15 per 100,000 mark.

The extra drinking has given them ten extra chances in a hundred thousand of getting the disease each year. Or to put it another way, an extra one in a 10,000 chance. So it seems there are at least two ‘factual’ ways of stating the same information:

1. Drinking more than two pints of strong lager each day makes you three times more likely to get mouth cancer.

2. Drinking more than two pints of strong lager each day, gives you an annual extra 1 in 10,000 chance that you will get mouth cancer.

Now, how you perceive and react to these two statements will be down to you as an individual, but I doubt there are many that would perceive and react to them in exactly the same way. The information has been presented in a way that fits in with the objectives of the people who created it.

Statement No.1 may be factually correct, (although, as we’ve seen, that is in doubt) but I think a lot of people would see it as misleading in the context of Statement No.2.

Disraeli is reported to have said that, “There are three kinds of lies: lies, damned lies, and statistics.” And well over a century later, his successors are still taking full advantage of the fact. There’s a growing tendency for information to be presented in easy to digest sound bites and this is what makes it easy. People are often busy, they don’t have time to take in huge swathes of information on the multifarious topics they’re expected to be up to date on these days. And that plays right into the hands of the persuaders who use statistics to shape our thinking, behaviour and actions.

I’m not here, to persuade you on the rights and wrongs of the alcohol/health debate. The truth is that I’m in the dark about it all just as much as anyone else. No I suppose my real purpose is to get you to take a critical look at any statistics you’re presented with, and ask yourself a few vital questions:

Where do the statistics come from?

Are there vested interests at stake?

Are the key factors properly defined?

Are there other factors involved which could affect or create the result?

What are the real numbers behind the headline figures and percentages quoted?

When or if you ever do this, you will give yourself a far stronger and more rational basis for the decisions you make, than if you allow yourself to be side-tracked by a wave of statistical misdirection. Plus of course, you get the added satisfaction of knowing that the smart-arsed, controlling and power obsessed politicians have failed to channel you down the alley that suits them best again.

And there are too few better reasons for doing anything than that. Now mine’s a pint and when you’ve done the maths, let me know what you’re having.

STATISTICALLY SPEAKING, MINE'S A PINT

   

2 Comments:

1. Unknown said...
   14 September 2010 at 22:49  
   haha ! brain on legs ! more people would understand statistics if they used the beer analogy !
   Katyjean Leslie said...
   14 September 2010 at 23:27  
   I'm having what you're having--no second thought I'll just have a glass of red instead. :)

Post a Comment