More or Less, and the Art of Not Being Fooled by Numbers

There is a particular kind of number that arrives in the news fully dressed and absolutely certain of itself. “Crime is up forty per cent.” “One in four of us will experience this.” “It would cost nine billion pounds.” The number is repeated, retweeted, put on the side of a bus, and within a day it has hardened into a fact. More or Less, a half-hour programme on BBC Radio 4 and the World Service, exists to walk up to that number, tap it on the shoulder, and politely ask where it thinks it’s going.

It is, against all odds, a delight. A weekly show about statistics ought to be medicine, and instead it is one of the most genuinely entertaining things the BBC makes — partly because catching a confident number telling fibs turns out to be deeply satisfying, and partly because of its host.

The man with the spreadsheet and the smile

More or Less has been running since 2001. It was the brainchild of the producer Michael Blastland and was first presented by the economist Andrew Dilnot; since 2007 it has been fronted by Tim Harford, the Financial Times columnist better known to readers as the “Undercover Economist”. Harford is the show’s secret weapon. He has the rare gift of sounding delighted rather than superior — a man who finds dodgy statistics not outrageous but fascinating, the way a naturalist finds a particularly cunning insect fascinating. The programme is made with the Open University, which is a polite way of saying it is educational, but it never feels like it.

The skills it quietly teaches

The real trick of More or Less is that, week after week, it drills a handful of mental habits into you without ever calling them a curriculum. Once you have them, you cannot switch them off. The main ones:

• “Is that a big number?” A total means nothing on its own. A million pounds is enormous for a village fête and a rounding error for the NHS. The show’s reflex is always to find the thing you should divide by — the population, the budget, the number of years — and only then decide whether to be impressed.
• “Where did this number even come from?” Almost every contested statistic dissolves once you ask who counted, how, and using what definition. Half of all arguments about crime figures, for instance, are really arguments about whether you mean recorded crime or the crime survey — two different instruments measuring two different things.
• Beware the percentage with no base. “Doubles your risk” is the favourite trick of the scary headline. Doubles it from what? If a thing happens to one person in a million, doubling it is still essentially nothing — but it makes a marvellous fright.
• Correlation is not causation, and the show will happily spend ten cheerful minutes on some pair of wiggly lines that move together for no reason at all.
• Watch your own feelings. This is Harford’s first rule, and the best one: notice when a statistic makes you want to cheer or sneer, because that is precisely the moment you stop checking it. The numbers that slip past us are the ones we wanted to believe.

The greatest hits

The show’s natural prey is the zombie statistic — the dodgy figure that will not die however many times it is debunked. The classic of the genre is the cheerful claim that we each swallow several spiders a year in our sleep, a “fact” with no source whatsoever that has crawled around the internet for decades; More or Less loves nothing more than tracking a creature like that back to its non-existent burrow.

It is at its best on the numbers that actually matter. It spent a good deal of airtime on the famous “£350 million a week” figure on the side of the Brexit bus, patiently explaining what that number did and did not include — the kind of public-service arithmetic that a surprising number of professional commentators couldn’t be bothered to do. It runs a “number of the week”, fields a steady stream of listener queries about claims that smell wrong, and has a long-running, very British affection for mocking the media’s habit of measuring everything in double-decker buses, Olympic swimming pools and areas the size of Wales. (The “size of Wales”, the show has noted, is doing an enormous amount of unexamined work in British journalism.)

There is real public good buried in the fun. When a programme demonstrates, week after week, that confident numbers are often wrong and that anyone can check them with a bit of curiosity and a calculator, it is handing out the cheapest and most powerful piece of self-defence in modern life.

Why a policing blog is recommending a stats show

Because policing runs on exactly the sort of numbers More or Less loves to interrogate. “Crime up twenty per cent” — recorded how, and over what baseline? A new tactic that “cut offending by half” — half of how many, in how few areas, compared to what? The habits the show teaches are the same ones underneath evidence-based policing: ask for the denominator, ask how it was measured, and be most suspicious of the figure that flatters your existing opinion. Half an hour a week of Tim Harford is, frankly, better professional development on this point than most training courses, and considerably more fun.

If you want more of him, Harford writes a weekly FT column, makes the splendid Cautionary Tales podcast, and wrote How to Make the World Add Up (published in the United States as The Data Detective), a book of ten rules for thinking about numbers. The tenth and final rule is also the whole philosophy of More or Less in three words: be curious.

So: go and listen to More or Less, and visit Tim Harford’s website while you’re at it. Then, the next time a perfectly confident number turns up in your timeline fully dressed and certain of itself, you’ll find you can’t help asking it where it’s going.

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Sources and further reading

• More or Less: Behind the Stats, BBC Radio 4 / World Service.
• Tim Harford’s website, and his book How to Make the World Add Up: Ten Rules for Thinking Differently About Numbers (2020).
• Michael Blastland and Andrew Dilnot, The Tiger That Isn’t: Seeing Through a World of Numbers (2007) — the book that grew out of the show.