Lies, damned lies and statistics

Author : Rob Ashton

Posted : 18 / 02 / 09

There are three kinds of lies: lies, damned lies and statistics. So said Benjamin Disraeli (and later Mark Twain, who was quoting him). Yet the public (and that’s all of us, at one time or another) continues to be sucked in by reports based on spurious logic and ‘facts’ of dubious provenance. If you’ve ever wondered why, you should read Risk, by Dan Gardner. It’s a fascinating explanation of why we fall for sensationalist writing every time.

The ‘link’ between the MMR triple vaccine and autism is one of the latest examples of the triumph of hype over reality. Reports of a link were based on a study involving just a handful of children. And countless subsequent and much bigger studies failed to confirm it. So the UK Government issued a statement saying that there was no link.

And that’s when it all kicked off – probably helped by the Government’s denial. (After all, if the Government’s denying it, then it must be true, right?)

The newspapers began filling up with studies of children who’d received the triple jab and then went on to develop the condition. Queues formed at clinics offering measles, mumps and rubella vaccination in three separate injections (a method that – unlike the triple jab – had never been tested on a large scale for either safety or efficacy). More and more people sought alternatives, such as homoeopathic ‘vaccination’. And – crucially – vaccination rates plummeted, to way below that required to produce ‘herd immunity’.

Now, years later, measles infection rates have climbed dramatically – more than 1300 last year in the UK alone, compared with just 56 ten years ago. The World Health Organization has abandoned its hope of eradicating the disease in the short term. And all because of a dubious, almost certainly unrepresentative study.

So why did we fall for it? It would be tempting to say that most people lack the technical knowledge to assess statistics properly. That may be true, but there’s more to it than that. Psychology plays a huge part. Our emotions are produced in the parts of the brain that evolved long before the parts that enable us to reason. And we make judgements – usually subconsciously – based on emotion (or ‘gut feel’) long before we use logic to work out if our gut feeling is right.

Then there’s innumeracy. According to French neuroscientist Stanislas Dehaene, we’re slower to compute 4+5 than 2+3. In fact, humans’ innate skill with numbers isn’t much better than that of rats and dolphins. It’s just that we’ve learned how to overcome it – with a lot of effort. (When polled, 45 per cent of Canadians didn’t know how many millions there are in a billion, for example.) So instead, people rely on gut feel: autism is a Bad Thing, so MMR must be bad. Logic never really gets a look in.

Risk explains in a clear and compelling way why our lives are dominated by irrational fears (as well as why we don’t worry about the things we should worry about). It’s the perfect antidote to the current epidemic of negative news.

And if you don’t want to read that, here’s another statistic for you, this time from the late comedian George Carlin: ‘Think about how stupid the average person is; now realise half of them are dumber than that.’