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.

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What is the EU customs union and will Brexit make us leave?

International trade secretary Liam Fox's job makes more sense if we leave the customs union. 

Brexiteers and Remoaners alike have spent the winter months talking of leaving the "customs union", and how this should be weighed up against the benefits of controlling immigration. But what does it actually mean, and how is it different from the EU single market?

Imagine a medieval town, with a busy marketplace where traders are buying and selling wares. Now imagine that the town is also protected by a city wall, with guards ready to slap charges on any outside traders who want to come in. That's how the customs union works.  

In essence, a customs union is an agreement between countries not to impose tariffs on imports from within the club, and at the same time impose common tariffs on goods coming in from outsiders. In other words, the countries decide to trade collectively with each other, and bargain collectively with everyone else. 

The EU isn't the only customs union, or even the first in Europe. In the 19th century, German-speaking states organised the Zollverein, or German Customs Union, which in turn paved the way for the unification of Germany. Other customs unions today include the Eurasian Economic Union of central Asian states and Russia. The EU also has a customs union with Turkey.

What is special about the EU customs union is the level of co-operation, with member states sharing commercial policies, and the size. So how would leaving it affect the UK post-Brexit?

The EU customs union in practice

The EU, acting on behalf of the UK and other member states, has negotiated trade deals with countries around the world which take years to complete. The EU is still mired in talks to try to pull off the controversial Transatlantic Trade and Investment Partnership (TTIP) with the US, and a similar EU-Japan trade deal. These two deals alone would cover a third of all EU trade.

The point of these deals is to make it easier for the EU's exporters to sell abroad, keep imports relatively cheap and at the same time protect the member states' own businesses and consumers as much as possible. 

The rules of the customs union require member states to let the EU negotiate on their behalf, rather than trying to cut their own deals. In theory, if the UK walks away from the customs union, we walk away from all these trade deals, but we also get a chance to strike our own. 

What are the UK's options?

The UK could perhaps come to an agreement with the EU where it continues to remain inside the customs union. But some analysts believe that door has already shut. 

One of Theresa May’s first acts as Prime Minister was to appoint Liam Fox, the Brexiteer, as the secretary of state for international trade. Why would she appoint him, so the logic goes, if there were no international trade deals to talk about? And Fox can only do this if the UK is outside the customs union. 

(Conversely, former Lib Dem leader Nick Clegg argues May will realise the customs union is too valuable and Fox will be gone within two years).

Fox has himself said the UK should leave the customs union but later seemed to backtrack, saying it is "important to have continuity in trade".

If the UK does leave the customs union, it will have the freedom to negotiate, but will it fare better or worse than the EU bloc?

On the one hand, the UK, as a single voice, can make speedy decisions, whereas the EU has a lengthy consultative process (the Belgian region of Wallonia recently blocked the entire EU-Canada trade deal). Incoming US President Donald Trump has already said he will try to come to a deal quickly

On the other, the UK economy is far smaller, and trade negotiators may discover they have far less leverage acting alone. 

Unintended consequences

There is also the question of the UK’s membership of the World Trade Organisation, which is currently governed by its membership of the customs union. According to the Institute for Government: “Many countries will want to be clear about the UK’s membership of the WTO before they open negotiations.”

And then there is the question of policing trade outside of the customs union. For example, if it was significantly cheaper to import goods from China into Ireland, a customs union member, than Northern Ireland, a smuggling network might emerge.

 

Julia Rampen is the editor of The Staggers, The New Statesman's online rolling politics blog. She was previously deputy editor at Mirror Money Online and has worked as a financial journalist for several trade magazines.