The prime minister’s speech at the Conservative party conference today was too vacuous to merit comment, but his deputy’s attempt at the world record number of mentions of ‘cheap labour from abroad’ does get me biting the bait.

There are several ways to avoid employing cheap labour from abroad. One is to employ cheap labour from Britain - lowering wages. Not, I presume, what anyone has in mind.

Another is to employ cheap labour from Britain by the back door. Simply paying higher wages would have several consequences. Businesses would have to pass on the extra costs and raise their prices, which would be bad news for British shoppers. Exporters would likely see customers, deterred by the higher prices, switch to things produced in other countries. So both inflation and unemployment could rise. Again, I suspect, not what anyone has in mind - though it is a scary consequence that could well arise if other plans fail.

Raising real wages requires an increase in productivity. This is not a blinding new revelation. It’s what the Industrial Strategy of Theresa May’s government was all about. It’s what the last Labour government sought with its drive for education, education, and education (echoed today by Johnson’s skills, skills, and skills). The UK does indeed need to solve its productivity problem. Identifying the problem is one thing, but real policies to solve it are another. There’s little sign that the current government really has any fresh ideas. But come on, we’re listening.

The economic impact of Brexit has generated much heated debate, but there is mounting evidence that the cost has already been considerable.

I have sporadically posted on this blog some forecasts from a neural network model that I have devised to predict the time path of the industrial production series in the UK. (For geeks, this has 24 lags of the seasonally differenced, logged variable as inputs, two hidden layers, and is fitted using a hyperbolic tangent.) Since the beginning of this year, however, the Office for National Statistics has published monthly data on Gross Value Added – a series which covers all parts of the UK economy, not just the comparatively small production sector. I’ve found it irresistible to use this series (data for which go back to 1997) to check out how, at June 2016, my neural network forecaster predicted output would evolve in the period after the 2016 Brexit referendum – and how that compares with the outturn. The graph below shows the forecast (in orange) and the outturn (in blue). The figures on the vertical axis are the annual change in logged output.

Beyond the first year after the referendum – when the depreciation of the exchange rate boosted exports – output growth in the UK has consistently fallen about 1.5 percentage points below the pre-referendum forecast. The cumulative effect of the shortfall in growth since the referendum amounts to the equivalent of around £900m per week. This finding is remarkably consistent with, and reinforces, the results from other (much less back-of-the-envelope) studies, including those by Gertjan Vliehge of the Bank of England, by Benjamin Born and co-authors, and by Josh De Lyon and Swati Dinghra at the LSE.

The fact that Brexit has already caused considerable economic damage seems inescapable.

It's a while since I wrote about the industrial production statistics. Recent months have seen a fall in output in the production sector, and in January this year industrial output was about 0.9% down on the same month a year ago.

The future time path of this series is especially difficult to predict given the uncertainties that still surround Brexit, but - even in the absence of further adverse shocks - my neural network forecaster suggests that the outlook over the next couple of years is subdued.

The government has published its long-awaited Industrial Strategy. It is well established that successful innovation often involves collaboration between public and private sectors, and the provision by government of a clear steer, with the promise of tangible support in the ‘Grand Challenge’ areas of AI, mobility, environment and ageing, is to be welcomed. There is some overlap between these areas and the launch of Sector Deals – partnerships between government and industry in the areas of AI, the automotive sector, construction, and life sciences. Future Sector Deals are heralded in the areas of creative, digital, and nuclear industries.

The Strategy places considerable emphasis on ‘people’, and stresses the need ‘to create good jobs and greater earning power for all’. The commitment is that ‘as the economy adapts, we want everyone to access and enjoy good work’. Within government, the Business Secretary is to take on responsibility for the delivering quality jobs. Building on the Taylor Report, he will develop ‘a set of measures against which to assess job quality and success’ – including: ‘overall worker satisfaction; good pay; participation and progression; wellbeing; safety and security; and voice and autonomy’. Some aspects of good work, as defined in the literature, are notable in that they do not appear in this list – notably flexibility and worker co-determination. Sector Deals are proposed as one mechanism whereby job quality can be enhanced; there will need to be others.

While employment in the UK has recovered well from the Great Financial Crash, it is widely recognised that the economy suffers a serious problem of mismatch in the labour market. The Industrial Strategy seeks to address one aspect of this problem – an absolute shortfall of certain skills. In particular, it identifies gaps in skills in science, technology, engineering and mathematics (STEM) and inequalities in educational achievement. The proposals in the Strategy to address these issues build upon innovations introduced in the last two Budgets – specifically in the provision of Technical level qualifications, apprenticeships, investment in mathematics education, and lifelong learning. The Strategy leaves another aspect untouched, however. Overeducation – or, rather, the allocation of well educated workers into jobs where they are less productive than they might otherwise be – has become an increasingly prominent issue. A part of any successful industrial strategy should therefore be to investigate how the operation of the labour market could be improved so that people can most effectively use the skills they already have.

The Strategy aims to tackle regional disparities in skills by devolving responsibility and budgets to mayoral areas. This is welcome, as local conditions are best understood by people working on the ground. More generally, the migration of highly skilled young workers to London is leading to coincident overheating in the capital and stalled recovery elsewhere. Investments made as part of the Industrial Strategy all have a spatial dimension, and active government support for initiatives ought explicitly to be conditional on promoting and maintaining regional balance; the need is for something with considerably more teeth than the regional mission of the British Business Bank heralded by the Strategy document. The Northern Powerhouse and Midlands Engine may be key to this – though it is critical that these initiatives should work together and not mutually frustrate each other. (If everywhere is a powerhouse, nowhere is a powerhouse – and there is a legitimate fear that regional politics may already have kiboshed George Osborne’s great idea.)

The UK has long lagged behind major competitor countries in its R&D spending, with combined public and private spending amounting to 1.7% of GDP. This compares with 2.8% in the US and 2.9% in Germany. The Strategy sets the goal of raising the proportion in the UK to 2.4% by 2027. This medium term goal appears modest, and indeed the Strategy itself sets an aspiration for a longer term target of 3%.

Overall, then, there is much to welcome in the Strategy. Productivity has been an issue in the UK economy for many years, and it is good to see government make explicit its responsibilities as an agent that can set the right environmental conditions for business to innovate. It is however a pity that the positive aspects of the Strategy are at odds with other relevant developments in the policy domain. The word Brexit does not appear in the document at all, and the only serious discussion of its implications for the substance of the Industrial Strategy is in a brief paragraph on the penultimate page. That aside, there is one page (with a lot of white space) that deals with migration – in a notably coy manner. The sad reality is that Brexit will take with one hand what the Industrial Strategy gives with the other.

The 'Economists for Free Trade' group has produced a document, authored by Patrick Minford, suggesting that Brexit will provide considerable economic benefits to the UK. It is interesting how this group has changed its name so that it looks as though more than one group is saying the same thing as them - they were 'Economists for Brexit' a few months ago.

Minford's basic argument for free trade is one that most economists would support. Trade (whether international or just me going to buy a coffee) happens because it's an exchange that makes both parties better off - and restricting that trade makes us worse off. International trade can be restricted by tariffs, but also by a whole plethora of non-tariff barriers (eg regulations of various kinds).

Minford emphasises tariff barriers - and (curiously, since he reckons Brexit will ‘mostly eliminate’ UK manufacturing) has a very manufacturing oriented view on this. But he's way out of date. The World Trade Organisation works to reduce tariff barriers worldwide - and we already benefit from that. There are still some tariffs, sure, but this really isn't the main thing that impedes trade.

That impediment comes from regulations - and the single market has done more than anything to remove it. Leaving the single market would put a whole lot of new barriers in place.

We don't know exactly where Minford's latest figures come from – his group is reporting the research bit by bit to try to get more publicity. But he undertook a similar exercise before the referendum, and it was clear from that that his model was ill-equipped to do the analysis. Indeed that exercise was widely panned. The model they use assumes a reduction in VAT instead of a tariff cut. It also assumes that the burden of regulations will decrease (and rather curiously models that by assuming a fall in the employer's rate of national insurance). Now if the EU regulations that our exporters face when they sell to the EU could be magicked away just by us leaving the EU, there might be some case for doing that, but otherwise it's bonkers. No, let's just tell it like it is... it is just plain bonkers.

Here's a picture that the Resolution Foundation produced, showing the 'before the referendum' and 'after the referendum' forecasts of economic growth made by every forecaster surveyed by the Treasury in its regular compilation of UK forecasts. The red dot is the forecast in July 2016 (after the referendum), the blue dot in June (before). In all cases but one, the expected impact of Brexit is clearly negative. The one exception is Patrick Minford.

The BBC – which, during this August silly season has given much prominence to the Economists for Free Trade report – needs to take a long, hard look at itself. By following a remit on 'balance' that is designed for political balance during general elections, not referenda, it has provided a completely unrepresentative view of the technical aspects of Brexit. (Bizarrely, it does the same thing with climate change when it gives the likes of Nigel Lawson a platform.) Balance should apply when there is a discussion about values - and of course there are some values-based arguments surrounding Brexit, and that is perhaps where the confusion comes in. But on a technical issue, where the science is clear, cranks should be treated as cranks. This really is flat earth stuff.

The UK government has published a document on future customs arrangements with the EU, in which two possible models are floated. The first of these involves a ‘highly streamlined’ system in which existing procedures are largely maintained alongside ‘technology-based solutions to make it easier to comply with customs procedures’.

The second involves the UK mirroring EU procedures when imports that will subsequently be exported to the EU enter the UK – thus allowing seamless movement of products between the UK and EU. Just how anybody will know which imports will later be exported is anyone’s guess. The government’s document refers to ‘simplifications for business, such as self-assessment’… which sounds a lot like complications for business.

The opportunities that will exist to strike trade deals with third party countries undoubtedly offer the UK some potential to benefit. This comes, however, at a cost – most notably bureaucracy. Clearly the UK should not be able to import products from a third country with a tariff that is lower than that applied by the EU, simply to export them to the EU without tariff. But it might be possible for UK businesses to process these products and sell their output to the EU at zero tariff. A call must then be made in determining how much processing or modification is needed in order to qualify a product for tariff-free export to the EU. Hence the need for rules of origin. Devising and subsequently implementing these rules is a huge undertaking – though technology (elsewhere in the document described as involving a ‘risk-based and intelligence-led’ approach) can certainly, albeit with imperfection, help.

The first option presented by the government’s document could be highly streamlined indeed if the UK were to be free to strike its own trade deals but did not take advantage of that freedom, and if it inherited all the trade arrangements already made by the EU (unlikely though this scenario might be). The existing customs union would then remain in all but name. A somewhat less streamlined mechanism would allow exceptions, albeit at cost that would need to be balanced against the benefits.

Whatever final arrangements are agreed, the UK government is proposing a transitional period. And – noting the British penchant for solving problems by changing the name – whatever it is called, at least the transitional arrangements should look very much like the customs union that currently exists.

Comments by Andy Haldane, chief economist at the Bank of England, comparing economic forecasts to the famous failure of Michael Fish to predict the October 1987 hurricane have been seized upon by the media. The relevant part of Haldane's commentary comes in the 5 minutes from 15m30s in this video.

A number of points are worth making about this. First, the specific forecasting failure that Haldane compares to Fish is that of the financial crash leading to the Great Recession. Some media outlets have suggested otherwise. Haldane does comment on the Bank's forecasts for the post-referendum period and notes that the economy has been more resilient so far than had been expected, but he continues to expect a relatively tough year in 2017.

Focusing then on the major forecasting failure in 2008, he identifies two contributory factors. The first (extending the analogy with meteorology) is a lack of data. With better data, better forecasts can be produced. The second is arguably more fundamental. As Haldane notes, the forecasting models tend to work well when the economy is close to equilibrium, but perform badly during the (more interesting) periods following a shock. They clearly need to be redesigned, and indeed are being redesigned, better to accommodate such extreme events. Much effort since the crisis has gone into developing macroeconomic models to include imperfectly operating housing markets, and it is likely that this effort will contribute to more successful forecasting in future.

That said, economies are made up of people with free wills, and forecasting in this context can never become an exact science. The forecaster's tools - be they VAR models, neural networks, DSGE models or whatever - allow the evidence to be marshalled systematically in order to produce informed estimates of the likely time paths of key economic variables. But they are informed only by what is known at the time of the forecast, not magically informed by data that are unavailable. That said, data on the vulnerability of the sub-prime sector were available in 2007, and it is certainly fair to say that these should have been given greater heed in forecasts.

However, while many laypeople consider forecasting to be a major part of what economics is all about, that perception is misleading. Most economics is based on generating hypotheses that are then tested on historical data. This allows some stylised facts to be determined, and helps us understand a complex world - for instance: production quotas raise the price of oil; or restricting trade is harmful to growth. The body of economic understanding that has developed in this way over many years is in no way challenged by the fact that (in common with everybody else) economists lack perfect crystal balls.