The risks of imprecision

When being half-right can be worse than being wrong.

Chris Dillow has a nice post up, "in praise of imprecision". He argues that, in far too many situations, we argue over tiny differences in estimates when the overall answer is basically known. What's GDP growth for last year? It's basically flat. Yet for all the arguments, you would think that the difference between -0.3 and -0.1 per cent – or even between -0.1 and 0.1 – was the difference between life and death.

He illustrates this with a few neat little guesstimates. For instance:

How much does welfare scrounging cost the economy? Guesstimate the number of scroungers. Guesstimate the value-added they'd contribute if they were working. Express as a proportion of GDP. For plausible values, it's a small number.

Or:

What impact will the small uprating in the minimum wage have on jobs? The adult rate will rise by 1.9%. Economists forecast inflation this year of 2.5%, so this is roughly a 0.6% real fall. Let's call the price-elasticity of demand for labour 1.5. The Low Pay Commission estimates (pdf) that 5.3% of jobs are around minimum wage ones. Multiply these three numbers together and we get 0.048%. Multiply by the number of jobs in the economy (29.73m) and we have roughly 14,000.That's roughly one-eleventh of the sampling variability of employment figures.

It's worth pointing out that the same idea has been applied pretty consistently to the claim that families with three generations of worklessness are a public policy problem. We don't know how many there are – and nor does the government, we now know – but study after study has suggested that the number is tiny.

There are only 15,000 households with two generations which have never worked, and a third of them are because the younger generation left full time education within the last year. On top of that, less than 1 per cent of young people have never worked by the age of 29, so the younger generation is normally the one most likely to pull a family out of worklessness. Whatever the number is, in other words, it's really, really small.

But it's important to note the downside to imprecision. The way common knowledge is disproved is rarely through wholesale upheaval. Instead, it's a gradual process of refinement: new estimates are put out, slightly lower than the old ones; then lower estimates still; and they get steadily lower, until suddenly you realise that the conventional wisdom was wrong.

It's a lot harder to turn an estimate of "recession" into an estimate of "growth" through gradual refinement than it is to turn an estimate of "-0.3 per cent" into one of "0.5 per cent". So there's more of a danger that we'll be stuck with half-truths.

But with that danger in mind, the absence of accepted imprecision is still keenly felt in Whitehall. Too frequently, "no statistics" is used to imply "we have no idea of the magnitude of this problem" – but that's not true. We actually know quite a lot, albeit imprecisely. The trick is acting on it.

Photograph: Getty Images

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

Felipe Araujo
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Hull revisited: What happens when a Brexit stronghold becomes City of Culture?

We report from Hull, to find out if you can replace the kind of nostalgia that led to a Leave vote with cultural investment.

At 75 metres long, the offshore wind turbine blade erected across Queen Victoria Square, in the heart of Hull, is a sculpture intended to mark a new chapter in the city’s history. For the next 12 months, Hull, a city of more than a quarter of a million people in the northeast of England, will be the UK’s City of Culture.

The 28-tonne blade hails from the local Siemens plant. The German technology company employs around 1,000 people in the area, making it Hull’s biggest single employer.

Seen up close in this context – laid dormant in the middle of a town square instead of spinning up in the air generating energy – the structure is meant to remind passersby of a giant sea creature. It is also, I’m told, an allusion to Hull’s rich maritime history.


All photos: Felipe Araujo

Nostalgia is a big thing in this part of the country. At one point, Hull was the UK’s third largest port but technology and privatisation drastically changed that. The battle over cod fishing with Iceland in the waters of the North Sea 40 years ago has also dealt a major blow to a region with a long and proud trawling tradition.

People here still talk about a bygone era when the fishing industry provided jobs for everyone and there was enough money to go around.

Fast forward to 2017, and the country’s new capital of culture is the same city that voted 67 per cent in favour of leaving the EU last June. Its new-found prestige, it seems, is not enough to erase years of neglect by a political class “too busy for commoners like us”, as one resident puts it.

“More than a message to Brussels, it [the Brexit vote] was a message to Westminster,” Paul Leeson-Taylor, a filmmaker born and bred in Hull, tells me. “For the first time in a long time people in Hull felt like they had the chance to change something, and they took it.”

But while speaking to people on the high street and hanging out with locals at the Community Boxing Club in Orchard Park, one of the city’s most deprived areas, there is one word that consistently popped up in conversation – more than any specific policy from Westminster or the much-hated rules “dictated” by Brussels. Foreigners.

According to official figures, Hull’s population is 89.1 per cent white British. Still, immigration is big on people’s minds here.

During my two-day stay in the city, I find myself being the only black person in most places I visit – I’m certainly the only black guy at the boxing club. So when someone begins a sentence with “I’m not racist but…”, I know a tirade on immigrants is about to ensue.

“There are just too many of them,” Nick Beach, an estate agent whose Polish clientele is a big part of his business, tells me as he is about to teach a boxing class to local children. Beach was born in Shepherd’s Bush, in West London, but has been living in Hull for the last 20 years.

“When I go down there these days and go into Westfield shopping centre, it is very rare you get an English person serving you now,” he says. “I just find it disappointing that you go into your capital city and you are a minority there.”

These are the much-discussed “left behind”, a white working-class community that has gained particular prominence in a time of Brexit and Donald Trump. Under economic pressure and facing social change, they want to have their say in running a country they claim to no longer recognise.

For Professor Simon Lee, a senior politics lecturer at the University of Hull, immigration is only a superficial layer when it comes to explaining the resentment I witness here. For him, the loss of the empire 70 years ago is still something that as a country Britain hasn’t come to terms with.

“The reason for us to be together as a United Kingdom has gone, so what is the project?”

As destiny would have it, a foreign company will now play a major role on Hull’s economic future, at least in the short term. In the wake of the Brexit vote, there were widespread fears Siemens would pull out of the region and take its factory elsewhere. With the massive blade looming large in the background, Jason Speedy, director of the blade factory in Hull, assures me that isn’t the case.

“The Brexit decision has made no difference. We have made our investment decision, so Siemens, together with the Association of British Ports, has put in £310m. It’s all full steam ahead.”

As Hull becomes the country’s cultural hub for the next few months, the hope is that its residents stop looking back and start looking forward.

For Professor Lee, though, until there is a complete change in the power structures that run the country, the north-south divide will remain – with or without the EU. “The way you kill nostalgia is to have something new,” he said. “The reason why people here are nostalgic is because there is nothing to replace it with.”

Felipe Araujo is a freelance journalist based in London. He writes about race, culture and sports. He covered the Rio Olympics and Paralympics on the ground for the New Statesman. He tweets @felipethejourno.