Whatever Mark Twain or Benjamin Disraeli may or may not have said on the subject, statistics are not in themselves a species of lie. In fact, they are at the heart of pretty much everything we do.

But while statistics are vital to understanding our world, they are often misunderstood. Which may not be because they’re being manipulated by liars – though that is sometimes the case – but because they are both open to interpretation and, let’s face it, sometimes difficult to interpret. Whether deliberately or not, the same statistical findings can often be presented to show very different pictures indeed.

Take these figures published recently by Statistics Netherlands, the official Dutch statistical office, showing an increase in e-cigarette use by young people between 2021 and 2022. The biggest reported rise is in the 16-20 age group (itself, of course, a somewhat arbitary grouping – why not 15-18, or 17-21? How different might those figures be?). But how big is big? It depends how you look at it.

You could say vaping in that age group rose by 252%, which sounds pretty high. You could say it more than trebled, which possibly sounds even more startling. Or you could say it rose by 6.3 percentage points, from 2.5% in 2021 to 8.8% in 2022.

All equally valid ways of reporting exactly the same figures. And, in fact, it does look fairly remarkable however you describe it – though without knowing how large the sample was in each year, it’s impossible to guess how representative the results really are of the young Dutch population overall.

 

Confirmation bias

 

The one thing we can say for sure is that the anti-tobacco (and anti-vape) Youth Smoking Prevention Foundation (Rookpreventie Jeugd) saw only what it wanted to see, taking the figures as proof of the message it was already committed to.

While it’s hard to deny the statement on the organisation’s TabakNee website that the figures “show a strong increase in e-cigarette use among young people”, there is simply no evidence there at all to support its assertion: “This shows that e-cigarettes have a strong appeal to young people and facilitate the transition to tobacco cigarettes.”

In fact it shows nothing of the sort – never mind that the repeated word “strong” is a matter of opinion, not fact, and never mind that the claims made about both smoking and vaping by 12-16 year-olds are directly contradicted by the table immediately below.

This is a clear case of confirmation bias at work, and it’s anything but an isolated case. In fact, the twin beliefs that a) vaping is rife and growing among young people, and b) it hooks them into smoking, have become orthodox views in many quarters.

So let’s look at some more figures, and how they might be interpreted.

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    As our sister service ECigIntelligence reports this week, a study newly published in the Journal of the American Medical Association (JAMA) found that young people who use e-cigarettes are indeed more likely to become regular smokers than those who don’t. If you’re on the lookout for bad news, there’s your headline.

    On the other hand, the numbers involved are nowhere near enough to alter the overall picture that smoking is simply going out of fashion with US youngsters. And indeed, of the very few vapers (and non-vapers) who do “try” combustible cigarettes, an almost vanishingly small number like smoking enough to go on doing it for long.

     

    Statistically significant doesn’t always mean significant

     

    As Lion Shahab, co-director of the Tobacco and Alcohol Research Group at University College London (UCL), pointed out, the statistics can be reported in starkly different ways. And the temptation for many will be to use them to exaggerate enormously the actual significance (as opposed to statistical significance) of what they reveal.

    You could say they showed that kids who vaped first were 81% more likely to try smoking than their non-vaping classmates. Yikes.

    Or you could examine the small numbers in addition to the big percentage, weigh up other relevant factors, and find that the absolute risk difference was a mere 0.88%. Not such an eye-catching headline.

    In the words of the study’s authors: “Although the significantly higher odds of continued smoking among e-cigarette users suggest a potentially important problem, the small magnitude of absolute risks and the minor risk differences in continued smoking between baseline e-cigarette users and non-users indicate a much less consequential problem: few adolescents are likely to report continued smoking after initiation regardless of baseline e-cigarette use.”

    And in the wise words of professor Shahab: “It is conceivable that these youth would have started using cigarettes instead anyway, and at possibly much higher rates, had they not opted to use e-cigarettes instead. Whatever the case may be, it is reassuring to see that whether or not adolescents use e-cigarettes, cigarette use, which is far more harmful, is becoming increasingly rare and regular, daily use has become virtually non-existent among youth in the United States.”

    Maybe it’s time to look for a different horror story.

    Aidan Semmens TobaccoIntelligence staff

    Image: Gerd Altmann

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    Aidan Semmens