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Page last updated at 10:52 GMT, Friday, 1 January 2010

One word we don't hear enough: 'Erm'

Michael Blastland
Different ways of seeing stats

In his regular column, Michael Blastland praises a revelation of statistical ignorance.

Journalists tell you stuff. We are purveyors of hot knowledge. Or so we think. Which is why ignorance hurts - hurts to feel, hurts to admit. To stand before a microphone or camera, to go in print and say "frankly, folks… I haven't the foggiest" is to feel news naked.

So at the end of a turbulent year, Go Figure bares all - and encourages others to do likewise - by recognising that though we may strut about with numbers, the future creases with laughter.

As Donald Rumsfeld once memorably said: it's not only what we don't know - the known unknowns - it's what we don't know we don't know.

Here, for example, is my chart of the year. I came across it for the first time a couple of months ago. It shows what the Bank of England thought would happen to economic growth.

Graph of GDP projection

Click on the link above to see what really did happen...

The BoE's famous fan charts show a wide range of possible futures, an indication of huge uncertainty. This one showed uncertainty about where we were then, let alone what the future held (see that the black line showing National Statistics data for the past has shading around it). But all this uncertainty is still not uncertain enough to contain reality.

How wrong can we be? Often more wrong than we think. This is good - as in useful - to know.

We might say something similar about swine flu, another of the year's big stories. Though plenty of numbers appeared - estimates for how many would catch it, and how many would die - no-one at the outset had a clue.

For the same reasons, my news phrase of the year would be: "Analysts were surprised". It was ubiquitous in business reports about, well, about half of everything that happened in business or economics this year. Isn't it time we stopped being surprised by surprises? If you see what I mean.

Uncertain man
The face of uncertainty... not one we're used to seeing on the news

About the economy, the BoE is relatively honest in admitting its limitations. There is another band on the chart, implied but un-seen, indicating a 10% chance of something unpredictable. The fan chart covers only 90% of the BoE's estimates of the future probabilities.

Numbers have a reputation for offering hard fact, implying precision, objectivity, and are sometimes used to mask ignorance, sometimes stupidly so.

That reputation isn't always deserved. Many statisticians obsess about how likely they are to be wrong. Yet in the place where much public argument takes place, among politicians and commentators, most of the doubt is lost.

No part of journalist training that I know of tells people how to report uncertainty. Instead, we seek out strident interviewees with granite confidence. Radio might even edit out the "erms".

Our temptation is to scorn ignorance. But ignorance sometimes knows something. For those of us whose job is knowledge, do we need to find better ways of reporting doubt, no matter how many numbers we have? Maybe.

Here's another possibility, that the public desire for certainty is so strong that the hesitant voice wouldn't be heard. Who wants to know what we don't know?

Happy New Year.

Graph of GDP projection, and what happened

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