Can't Count

First, the UN, for making a mockery of a serious business. It said in November that HIV-Aids was spreading, while revising its figures for the number of sufferers down. That's right, they've gone up — to a lower number (from about 40 million to 33 million). Researchers admitted that their sampling (in urban maternity clinics) had been biased. Pregnant women turn out to be a poor sample of the rest of the population because — guess what? — they've all had unprotected sex.

Can't Aim

Targets are the mother of invention. But few surpass the creative zeal exposed in May by the Police Federation. The target was to solve more crimes. Hence a child in Kent arrested for throwing a cream bun at a bus; a man in Cheshire “found in possession of an egg with intent to throw”; and, best of all, a child accused of keeping £700 raised as sponsorship for Comic Relief, leading to interviews of every sponsor. The result: not one crime, but 542, the Federation said, and all solved. We can all sleep safer.

Can't Compare

Rudi Giuliani, aspiring US President, had prostate cancer. His chance of surviving in the US, he said in August, was 82 per cent; here, “under socialised medicine”, about half as good. There was even a graph to prove that the NHS was a killer (reproduced below).

Was Rudi right? Here's a clue. Is it remotely likely that prostate cancer strikes three times as many in the US, or just that three times as many instances are diagnosed? Bump up the number of diagnoses — when deaths stay much the same — and, presto, there's your massively higher survival rate. Innumerate, but brilliant.

Can't Believe

It is a truth universally acknowledged that rail safety deteriorated after privatisation. Make that a falsehood. Railway inspectorate data shows unarguably that accidents not only fell, but fell faster after privatisation than before. More than 100 people lived who might otherwise have been expected to die had British Rail's rate of progress continued. A prize then to the deputy leadership campaign of the Labour MP Jon Cruddas in

June, citing safety as a reason to renationalise the railways.

Can't Count II

What migrant workers? Oh, those migrant workers. Surveys to identify them missed whole categories by, for instance, omitting to count migrant workers who had been in the country for several years. In two days in October the official total since 1997 was revised from 800,000, to

1.1 million, then 1.5 million. The nation twigged that migrants aren't counted at all, but sampled, with all the flaws that sampling entails.

Can't Say

“Smoking ban cut heart attacks in Scotland by 17 per cent”, researchers and politicians trumpeted to the world in September through press releases, a conference and interviews, all faithfully reported. It was the ban what done it, they said... until six weeks later when official data halved the drop — to 8 per cent — against a trend immediately before the ban of a 5 or 6 per cent drop, and a fall a few years ago of 11. All of which makes it hard to be sure what, if any, effect the ban really had. The researchers went strangely silent.

Can't Eat

Save our bacon buttie was the call in November when processed meat was declared deadly. An extra 50g of bacon every day puts 21 per cent on your risk of colorectal cancer. But the right question wasn't asked: 21 per cent of what? What's the risk to begin with? Clarity is actually simple: in 100 men, five typically get colorectal cancer, that's the risk we begin with. If they all eat extra bacon every day, six will. Eaten even this often, it makes no difference to 99 in 100.

Can't Tell Big from Small

“Unpunished: the 3,000 crimes committed by under-10s” cried headlines, as terrified Britain opined on whether to lower the age of criminal responsibility. But note there are nearly 3 million children aged 6 to 9 (granting that few under 6 are likely to be villains). That's a ratio of one crime for every 1,000 six to nine-year-olds. Note too, 3,000 crimes, not criminals, and the ratio probably doubles, or more. Some kids do foul things; most of these, the police said, were trivial.

Can't Compete

Another day, another fatuous international comparison: as Britain went helter- skelter down to 15th in the league table for reading ability, it emerged that most of the new countries above us hadn't actually been surveyed before. It was like telling a man he'd grown smaller because a new basketball team was in town. It's not that we've become bad, but perhaps that we always were.

— Michael Blastland and Andrew Dilnot are the authors of The Tiger that Isn't: Seeing Through a World of Numbers

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