Sunday 19 August 2018

Dealing with forecast uncertainty

A few months back I produced a piece which looked at the economics of the World Cup. The fun part of the analysis was to look at the expected performance of each team based on a number of factors. Using a statistical model, based on the Poisson distribution which took account of the strength of each team and the quality of the opposition, I came up with a ranking that was pretty close to that of the bookmakers. The bit that everyone focused on, of course, was the tip for the tournament. As it happened, my statistical model made Germany favourites to win, but as we all now know Germany failed to qualify from the group stage.

Of course, the press gleefully highlighted the prediction error – as they did with all those who failed to correctly predict the winner. The only thing was, I didn’t really get it wrong. Although I made Germany the most likely team to win, I only assigned an 18% probability to their chances of tournament success, implying an 82% chance of not winning. In bookmakers’ parlance, I put the odds against Germany winning the tournament at 4-1. Sure enough, Germany did not win the tournament – the most likely outcome predicted by the model.

The idea that we apply probabilistic assessments to outcomes strikes me as a sensible way to think about an inherently unknowable future and it is a point I have made on numerous occasions previously (here, for example). At a time when macroeconomics has come in for considerable criticism for its failure to accurately forecast future events, understanding the process of how forecasts are made is worthy of further investigation.

Critical to understanding the nature of an economic forecast is that they are heavily conditional. In fact everything in economics depends on everything else, so if some of the conditioning factors change the forecast is likely to be blown off course. Consider the case of forecasting how a central bank might set interest rates on the basis that it follows an inflation targeting regime. We assume that inflation is a function of the amount of spare capacity in the economy – the less slack there is, the more competition for resources which then bids up their price. The choice of model itself is a major conditioning factor. If central banks use different metrics in making their decision, this raises the chance that the forecast will be wrong.

But let us pursue our assumption a bit further: In order to determine how much slack there is in the economy, we have to understand trends on both the demand and supply side which introduces additional conditioning factors. On the demand side we need to know what is the likely path of driving forces such as incomes, taxes (which influence disposable incomes and labour supply decisions) and wealth (which can be used to finance consumption and which also impacts on desired saving levels). On the supply side, we need to know something about changes in the capital stock, which requires assumptions for investment and the rate of capital depreciation; the size of the labour force and the path of multifactor productivity. It should be pretty obvious by now that in a short space of time, we have identified a whole chain of events which could impact at any point to change our assessment of the amount of spare capacity and thus the potential inflationary threat.

It is pretty unlikely that we are going to predict all the inputs correctly, with the result that there is a considerable margin of uncertainty associated with our projections. When the economy is subject to an exogenous shock, such as in the wake of the Lehman’s bust or Brexit, the degree of uncertainty is significantly raised. Consider the UK in the wake of the Brexit vote: There was no effective government following David Cameron’s resignation and it was totally unclear whether the UK would invoke Article 50 in June 2016, as some had advocated. In this vacuum of uncertainty, large forecasting errors were made in the immediate post-referendum environment.

But contrary to the statements made by a number of pro-Brexit politicians about how the doomsayers were wrong before the referendum, much of what the forecasting profession said has stood up to scrutiny. Notably that the pound would collapse, inflation would rise and the economy would grow more slowly and thus suffer a loss of output relative to the case of no vote for Brexit. Obviously we don’t know what will happen from here because we do not yet know the nature of the UK’s future trading arrangements with the EU. One way to proceed is to outline a number of scenarios and assess what might happen to growth in each case. If we assign a probability to each scenario then our best guess for output growth is the probability-weighted average of the outcomes.

But how useful is the single point estimate for annual growth over the next five years in the case of Brexit? The answer, I suspect, is not much. We are more interested in the cost of our forecast being wrong (i.e. whether we are too optimistic or pessimistic relative to the outturn). We thus should focus on the loss function, which measures the cost of being wrong. This is not something that gets the attention it perhaps deserves because it can be a costly and time-consuming exercise. Instead we generally define a range of forecast extremes which encompass a median (or modal) forecast. The extent to which this forecast lies in the upper or lower half of the range determines the extent to which forecast risks are asymmetric, giving us some idea of the costs of being too optimistic versus being overly pessimistic.The Bank of England has long been an advocate of this approach (see chart, which assesses the range of outcomes for the August 2018 inflation forecast).
  
My efforts at forecasting future economic events are guided by Niels Bohr’s quip that “prediction is very difficult, especially if it's about the future.” Experience has taught me that we should treat our central case economic predictions as the most likely of a range of possibilities, and nothing more. After all, there is no certainty. When Germany can underperform so spectacularly on the international football stage, even the most confident of forecasters should take note.

Monday 13 August 2018

This currency is a turkey

The top market story of the day has been the collapse in the Turkish lira which went from 5.60 against the dollar on Friday to around 7.00 at the time of writing – a collapse of 25% in one session. It is not as if the lira is coming off a period of overvaluation – quite the opposite in fact, since the currency has been sliding throughout much of the year. The root cause of the lira’s initial weakness was the failure of the central bank to tighten policy earlier this year. This resulted in the currency coming under pressure over the first four months of 2018, followed by a sharper depreciation following President Erdogan’s remark in May that “I will emerge with victory in the fight against this curse of interest rates … Because my belief is: interest rates are the mother and father of all evil.”

In short, Erdogan has peddled the view that rising interest rates result in higher inflation. To say the least, it is unconventional (though not necessarily wholly wrong if you have interest-rate linked products such as mortgages in the CPI basket, as the UK discovered 30 years ago, though that is not the case in Turkey today). As a result, Erdogan has browbeaten the central bank into holding off from monetary tightening. To make things worse, the political standoff between the US and Turkey has intensified in recent weeks, culminating in Friday’s response by Donald Trump to double the tariffs on imports of metals from Turkey. It is thus understandable that investors are feeling nervous and as a result Turkey has come into the market’s cross-hairs. But with the central bank’s credibility having been badly battered by its actions this year (or more precisely, by its inaction) it is difficult to see what it can do to stem the lira’s decline. It could jack up rates but once market confidence has been lost in the way that Turkey has experienced, this is nothing more than a futile gesture. Even a 100% annual interest rate amounts to just 0.19% on a daily basis. This is equivalent to trying to stop an elephant with a pea shooter. In other words, futile when the currency can decline by 25% in one day.

The other alternative is capital controls. One of the basic axioms of international economics is that economies cannot simultaneously run an independent monetary policy, a fixed exchange rate and free capital movement (the famous trilemma). On the assumption that Turkey wishes to regain some control over its currency, and on the basis that domestic monetary policy is likely to prove ineffective (as noted above), some restrictions on capital outflows appear to be necessary. Bear in mind that Turkey already runs a current account deficit, equivalent to around 5.5% of GDP last year. It thus has to borrow from the rest of the world to cover the fact that domestic investment is greater than domestic saving. Foreign investors are not going to be keen to lend to Turkey if they cannot get their money out. Theory would thus suggest that Turkey will have to deflate its economy in order to redress the savings-investment balance whilst the capital controls are in place.

This is exactly what the Asian Tigers did in the 1990s when currencies in the region came under speculative attack (though to be more precise, the policy was forced upon them by the IMF as a condition for financial assistance). Obviously, this does not bode especially well for Turkey’s near-term growth prospects, but people said very much the same regarding Thailand and Korea in the 1990s – and look at them now! There again, it did take five years for real GDP in Thailand to get back to pre-crisis levels.

The full effects of the Turkish lira collapse will continue to play out over the longer-term. Perhaps the Russian currency collapse of 2014-15 can offer some pointers. Ordinary citizens certainly did not escape unscathed, with consumers required to tighten their belts considerably. As in Russia, Turkish inflation is set to spike much higher. But whereas Russian inflation surged from 8% to 17%, Turkey is starting from an already-high rate of 16%. And the Russian central bank emerged with great credit as it managed the currency shock – the Turkish central bank’s stock is not exactly high.

One of the lessons we have learned from past currency crises is that what matters for the future is the nature of the policy response: Credibility can be regained if the authorities are prepared to make some hard choices. Moreover, despite the chatter suggesting that this could mark the start of an EM rout, we should not forget that Turkey’s problems are largely homemade. This is an object lesson of what happens when we try to run economic policy along populist lines, with Erdogan’s attempt to hold down interest rates to make life easier for his supporters about to backfire spectacularly. Populists of the world take note.

Saturday 11 August 2018

Howay the lads: The economics of Newcastle United

Less than four weeks ago global audiences were gripped by the World Cup, which attracted a global audience of 3.4 billion people who watched at least some of the tournament on TV. But it is back to the grind of the domestic scene as the first round of English Premier League matches kicks off this weekend. This is where players, who just a few weeks ago were gracing the world scene, earn their corn: Footballers in England can look forward to 38 league games and numerous domestic cup games, whilst the top players must also face up to the rigours of the Champions League.

The best players get well paid for their trouble. According to the Global Sports Salary Survey for 2017, the average salary for players at the two Manchester clubs, United and City, was £5.2 million ($6.8 million) per year. Clubs such as Barcelona, Paris St. Germain and Real Madrid shell out even more, with the average Barca player earning 25% more than their counterparts in Manchester. If a top flight player can expect to play 60 games per season, an average player in Manchester earns around £87,000 per game – or nearly £1,000  for each minute they are on the pitch. Clearly, that is an awful lot of money to shell out but the simple truth in sport is that if you want to win, you have to pay.

Contrary to the view on the terraces that clubs have to spend in the transfer market to be successful, the academic evidence clearly shows a stronger correlation between the wage bill and football success. This reflects the fact that clubs which spend most on wages tend to attract the best players. As the chart below shows, there is a decent linear relationship between the average wage per player and Premier League position in season 2017-18. Those clubs lying above the line underperformed relative to their wage bill whilst those below the line outperformed. This brings me nicely to one of own personal pet peeves since I am a long-suffering fan of Newcastle United – a club that is perennially perceived to be one of the great underachievers of modern English football.

As is evident from the chart, Newcastle significantly outperformed its wage bill last season largely thanks to the outstanding performance of the manager Rafa Benitez, who has an impressive managerial CV at some of Europe’s top clubs. Although it is only one data point, it is testimony to what a good manager can achieve without spending huge amounts of money. But it is hard work to operate like this on a sustainable basis and Benitez is used to competing at the top of the table with clubs like Liverpool, Inter Milan and Real Madrid (his last job before Newcastle). Like most Newcastle supporters, I am frustrated at the refusal of the club’s owner, retail magnate Mike Ashley, to loosen the purse strings which would allow Benitez to strengthen his squad to improve the chances of winning something. Indeed, there is a common perception that Ashley is the root of all evil at the club (see, for example, this article from the German magazine Kicker). But a closer look at the club’s finances make it clear that matters are far more complicated than they appear on the surface.

At first glance, the club would appear able to spend more. Since he took the job in March 2016, Benitez has recouped almost £58 million in net transfer fees alone. Moreover, since Ashley took control of the club in 2007, he has sanctioned an average net spend of just £11 million per year which is around the going rate for one player these days – one new player per season is just not going to cut it. This failure to invest means that in the last nine years the club has suffered two of the six relegations in the club’s 126 year history. And the costs of relegation are significant. Relegation in season 2015-16 cost the club £40 million in lost revenue with the result that a modest profit of £4.6 million in 2016 was transformed into a loss of £41 million. Were Newcastle to have spent more than one season in the Championship (the second tier), parachute payments available to relegated clubs would have dwindled and revenue losses would have been even higher.

Doubtless Ashley would retort that increasing outlays would bring in little additional revenue. Each gain in league position only generates an additional £1.9 million in prize money. In order to justify spending an extra £10 million would require the club to improve its position by 5 places. Having finished 10th last year it would be a tall order for the club to be in the running for a Champions League spot. But this penny-pinching approach is at the extreme end of the feast or famine approach which characterises football finances. Once we factor in TV revenue, Newcastle generated a total of £123 million last year purely from being in the Premier League.

There again the club’s wage bill in 2017 was around £112 million so a large part of the Premier League revenue is eaten up by costs. And the club is also heavily indebted (as indeed are many top flight clubs in England) with the total amountng to £144 million as of mid-2017 which is more than 100% of income. Fortunately, the debt is held by Ashley and is not subject to interest charges, and the owner’s strategy appears to be to manage the club such that current costs are met out of current income. Whilst this is a laudable aim – and debt has been broadly stable over recent years – it is not enough to satisfy fans who want to see the club actually win things. Winning the FA Cup would generate £6.8 million in prize money (even reaching the final would bring in another £5 million) plus gate receipts. However, the EFL Cup (as this season’s League Cup is called) is not even worth bothering with on a financial basis (here).

As a Newcastle fan, I want to see my club win things or at least make a decent attempt at doing so. But the economics of running a football club mean that unless you have ultra-deep pockets it is difficult to compete on a consistent basis. In many ways, Ashley has not been a good steward of the club: He is a lousy communicator, is overly parsimonious and fails to appreciate the importance of the club to the local community. But it is hard to disagree with the underlying business ethos that the club must live within its means. The romantic in me harks back 20 years to the days when Kevin Keegan’s team swashbuckled their way up the league, spending huge amounts of money in the process. But the legacy is a large debt which, two decades on, continues to constrain the club’s ambition.

Monday 6 August 2018

The reality of real interest rates

With interest rates having been so low for so long in the industrialised world, policymakers are increasingly waking up to the need to take away some of the monetary stimulus put in place almost a decade ago. The Federal Reserve started its tightening process in December 2015 and it was joined last week by the BoE which nudged the benchmark rate above 0.5% for the first time in over nine years. But it is generally recognised that although central banks are beginning to take away some of the monetary stimulus, they are not heading back to pre-2008 levels any time soon.

In a bid to understand how much headroom there is for monetary policy, central bankers are increasingly paying attention to the neutral real interest rate, described by former Fed Chair Janet Yellen as “the level that is neither expansionary nor contractionary and keeps the economy operating on an even keel.” More formally, it can be thought of as the rate which balances desired wealth holdings with desired capital holdings. This is the theoretical framework attributable to the Swedish economist Knut Wicksell in which equilibrium in both the goods and financial assets market is simultaneously derived.

The analysis published last week in the BoE’s Inflation Report explained this framework very nicely (see chart) and noted that we can think of the rate as being driven by long-term secular factors (R*) and a short-term component reflecting cyclical issues (s*). John Williams, recently elevated to the role of President of the New York Fed, noted in a speech earlier this year that in his view the real neutral rate (R*) in the US is around 0.5%. The BoE comes to a similar conclusion for the UK, pointing to R* in the range 0%-1% (with a modal estimate of 0.25%).

These estimates are around 200 bps lower than those prevailing 20 years ago. So what has changed? One of the key secular factors is demographics. As people live longer they have to save more for retirement with the resultant increase in savings putting downward pressure on interest rates (a shift in the red line to the right in the BoE’s chart). Another important factor is the increased demand for safe assets which has driven down returns on government bonds relative to those on riskier assets, and which also has the effect of driving the red curve further to the right. A third factor is the slowdown in productivity which has reduced business demand for capital, thus putting additional downward pressure on the interest rate (the blue line shifts to the left). Finally, a rise in the government debt-to-GDP ratio may depress the real rate via a crowding out effect since this reduces the quantity of capital available to finance an expansion of the business capital stock.

As to how these factors will play out in future, there is general agreement that slower population growth in the western world will not reverse the current trend ageing of the demographic profile. Consequently, retirement saving is likely to remain a key driver putting downward pressure on the equilibrium rate. It is less clear what will happen with regard to productivity. It may recover, or it may not, but we cannot say for sure that it will remain as sluggish as it has over the last decade. In any case, as labour force constraints begin to bite, it is possible that demand for capital will rise which will act to raise the neutral rate. But it is unlikely that government debt-to-GDP ratios will decline rapidly any time soon, which argues for continued downward pressure on the equilibrium rate.

However, some doubt has been cast by the BIS on the link between interest rates and the observable proxies that are conventionally used to measure the savings-investment balance. Part of their argument rests on the fact that much of the analysis is based on data only back to the 1980s and that taking the data back to the late nineteenth century suggests a weaker link between them. That said, the BoE’s analysis is  based on a long-run of data extending back more than 100 years and they come to much the same conclusion as the rest of the academic literature, which weakens the BIS criticisms to some degree.

However, the BIS does raise another important question:  Much of the literature assumes that monetary policy is neutral in the long run and that only real factors influence the real interest rate. But is this necessarily true? For one thing, the expected wealth demand function may be determined by the actions of central banks themselves as interest rate expectations influence portfolio choices. Another objection is that we may underestimate the key channels through which monetary policy exerts a persistent influence over real interest rates (e.g. the inflation process or the interaction between monetary policy and the financial cycle). These are serious criticisms, although the BoE’s framework introduces the short-run variable s* into the framework, and whilst we can estimate R* using conventional measures, the BoE does not try to put a numerical value on s*. However, it does suggest that in the longer-term the s* component will tend towards zero (although it may not be zero at any given time).

What are the takeaways from all this? First off, if we add a 2% inflation rate to estimates of the real neutral rate, we end up with a neutral funds rate in nominal terms of around 2.5%. With the Fed funds target corridor currently set at 1.75%-2.0%, we might only be three 25 bps hikes away from the neutral rate. Similarly, the UK neutral rate is estimated in the range 2%-3% so we do appear to have more headroom. Nonetheless both estimates suggest that interest rates will not get back to the pre-2008 rates of 5%-plus for a long time to come. Welcome to the new normal.

Tuesday 31 July 2018

The case for a UK rate hike

The Bank of England is widely expected to raise interest rates by 25 bps this week, taking them above 0.5% for the first time since March 2009. The markets seem convinced, pricing such an action with a probability around 90%. It would be a major surprise if the Bank were not to deliver, with the markets so apparently sure. Indeed, if the BoE had a problem with current market pricing it would almost certainly have said something before now to try and nudge expectations. The fact that it has not done so is a strong indication in favour of a policy tightening. (If a rate move is not forthcoming … well, that is another story and we will deal with it if it happens).

There are those who believe that raising rates is a mistake (or at the very least that there is no need to act now). Their argument is sound enough: Price inflation is slowing; wage inflation is not picking up as anticipated and there are sufficient headwinds from Brexit that caution is warranted. If we were talking about an economy in which rates were a little bit higher than those introduced when the economy was about to fall off a cliff in 2009 I would be a bit more receptive to that view. But we’re not! Whilst Bank Rate of 0.5% may have been appropriate for an economy which was expected to contract by more than 3% in real terms, it is hard to make the case that is still the right interest rate 9 years later for an economy expected to grow by 1.5%.

For quite some time, I have believed that the UK rate setting process has taken an overly short-term approach to monetary policy. By looking only at short-term issues (e.g. the latest inflation or growth data) policymakers have been able to defer the need for a policy tightening. But in so doing, they appear to have suffered from what we might term “horizon myopia” without taking account of the fact that all these short terms eventually add up to an extended time horizon.

My argument for raising rates is the same as it has been for the last 3-4 years: The current interest rate is too low for general economic conditions. Those who believe that nominal GDP growth should act as a benchmark for the policy rate – and I am semi-persuaded of the merits of such a policy – argue that UK interest rates have deviated from GDP to an unprecedented degree in recent years (see chart). By itself, that is not proof of anything but it is an indication of the extent to which financial rates of return are out of line with those in the real economy which is likely to lead to economic distortions.


Arguably, excessively low (or high) interest rates distort capital allocation decisions – for example, by propping up zombie firms (though I am not sure that is a problem in the UK right now). However, they do distort savings choices. If returns to saving are low, this is a strong argument in favour of spending rather than saving. This is, of course, precisely what policy was designed to achieve during the depths of the recession but is it really necessary almost a decade on? And as I have pointed out previously, the longer interest rates are held at emergency levels, the bigger the risks to future generations of pensioners whose pension pots will not grow as rapidly as they ought. Indeed as John Authers noted in the FT last week whilst low interest rates prevented an economic meltdown, “it grows ever clearer that risk has been moved, primarily to the pension system.”

In my view, this is another strong argument in favour of modestly tightening monetary policy. At this stage we are not talking about a dramatic stamp on the brakes, but allowing rates to edge upwards by (say) 50 bps per year for the next couple of years would take some of the heat out of the problem. Whether the BoE will be in a position to do that depends, of course, on the extent of any damage that Brexit inflicts on the UK economy.

Sunday 29 July 2018

Self-inflicted wounds

It has become clear over the last twelve months how woefully unprepared the British government is to negotiate an exit from the EU. As the play in the theatre of the absurd continues to unfold, we are faced with the prospect of the British government having to take steps to secure food supplies in the event of a no-deal Brexit, which has lit up social media sites with posts displaying a mix of trepidation and withering scorn. As more than one person has commented, we appear to have gone from “Vote Brexit to save £350 million a week” to “Vote Brexit and we will ensure that the food doesn’t run out.”

Against this backdrop the latest missive from the brains behind the drive to sign new trade deals – none other than trade secretary Liam Fox – arguing that ‘No deal’ is preferable to delaying the Brexit process is beyond stupidity. You may recall a year ago, Fox claimed in a radio interview that “the free trade agreement that we will have to do with the European Union should be one of the easiest in human history.” This is the same Liam Fox who said two years ago that “we're going to replicate the 40 EU free trade agreements that exist before we leave the European Union so we've got no disruption of trade.” With seven months before the UK leaves the EU, let us consider how many of those trade deals Fox has actually signed (clue: It’s an integer less than one). So you will forgive me for not taking Fox’s latest assertion at face value that “extending Article 50 is the definition of failure for the government.”

Fox went on to say that “The public have told us, it wasn’t a consultation, to leave the European Union, and the public already wonders why it’s going to take more than four years after the referendum for us to fully remove ourselves from the EU. To attempt to extend our membership even longer, many voters would regard as a complete betrayal by the political class.So where to start with this one? How about the fact that the referendum was in effect a consultation – it certainly was not legally binding. And why is it taking four years? Because it is a difficult process and one which if rushed will lead to far worse outcomes than are necessary. The biggest betrayal of all would be to sell out the public in order to deliver a Brexit which leaves people worse off. And if he thinks people are angry with the way politicians have handled Brexit so far, wait until it is bungled.

Another of the Brexit-at-any-price brigade, Daniel Hannan, yesterday told readers of the Daily TelegraphLet’s call the EU’s bluff and prepare for a no-deal.” Hannan’s argument relies on the old nonsense that “they need us more than we need them.” This is simply wrong. Around 47% of UK exports are destined for the EU27 with only 16% of EU exports headed to the UK, and the Telegraph is guilty of peddling fake news by suggesting otherwise. You can argue, as Hannan does, that the EU is being unreasonable in its approach, and we can look at that another day. But all sane commentators knew that the EU held the whip hand in negotiations and expecting it to act in any other way than to look after its members interests denotes irresponsible levels of naivety.

There is nothing new in any of this, of course. I think the Brexit ultras are wrong and they believe me to be a Remoaner, afraid of looking to new horizons. So let’s have a look at some evidence. Over recent months I have been looking at gravity trade models of the UK to assess the impact of a hard Brexit (the final results are likely to be published in a few weeks’ time). On my estimates, a no-deal Brexit will cost around 8% of UK export volumes and impose a hit of 3% on imports. With exports falling more than imports, this implies a one-off reduction of 1.5% in GDP. That may not sound like a lot but if we impose these results on a structural model and run them over a 15 year horizon, we end up reducing real GDP by 4% relative to baseline and real incomes by 3%. As a result unemployment rises and public finances turn out significantly worse than they would otherwise be. I can’t find the Brexit dividend to fund higher NHS spending (neither can the OBR). 

With support for a second referendum apparently mounting, the whole Brexit debate is reaching a tipping point. I have to stress that I am no great fan of this idea although I don’t buy the will of the people nonsense (remember, only 37% of eligible voters opted for Leave). But the decision to leave the Single Market and Customs Union is economically crazy and was certainly not on the ballot paper. However, if Theresa May continues to believe that this is what people voted for, then a second referendum may indeed be required to check whether it really is “the will of the people.”

I do wish there were more important things to write about but Brexit appears to have become an all-consuming part of this blog. However, it is THE economic question of my lifetime – and it is being driven by ideological politics. But as the journalist James O’Brien put it, “The one thing I still can’t quite get my head round: It’s optional. It’s a choice. It’s voluntary.”

Thursday 26 July 2018

You don't know what you've got 'til it's gone

Viewed in a global context Brexit is very much a sideshow. However, it is all part of a global backlash against the status quo which is perceived to have acted against the interests of citizens in the developed world. Nowhere is this more evident than in the actions of the Trump administration which earlier this month imposed higher tariffs on the first $34bn worth of imports from China and threatened to escalate still further, thereby risking Chinese retaliation and a further step on the path towards a global trade war. The biggest danger in all of this is the prospect that the current global economic architecture could well be jeopardised, which may not be perceived to be a problem in Hicksville USA or Smalltown England, but might result in turning our back on the most successful period of prosperity generation in world history.
To put some figures on it we rely on the database put together by the late Angus Maddison which looks at very long runs of GDP data. Measured in real terms, the increase in world GDP between 1950 and 2000 outstripped anything seen in the previous two millennia, rising at an average annual rate of 3.9% versus 0.2% in the preceding 1950 years (chart). The same is also true of the US, although its most rapid growth occurred during the early years of the industrial revolution. Nonetheless, average US growth of around 3.5% per year between 1950 and 2000 compares pretty favourably with the 4.4% rate recorded during the nineteenth century. Growth is not everything, of course. When comparing living standards, what matters is the absolute level of income. Whilst it is true that US per capita income growth has stalled over the last decade, the US still ranks ninth in the world behind three oil-rich Gulf states, four smaller European economies (Norway, Luxembourg, Switzerland, Ireland) and Singapore. For the record, Chinese real income per head is just 23% of US levels.

It might suit some American politicians to claim that their country has never had it so bad, but the US is still a pretty good place to be. The US has attained these lofty heights, thanks to an exceptional period of technical innovation – which it drove – and a huge rise in world trade which allows it to buy products more cheaply from other parts of the world, thus allowing American citizens to spend their excess income on other products. Whilst it is true that China is closing the gap with the US, per capita GDP growth has recently slowed to an annual rate of less than 3%. At current rates, it will take China 55 years to reach current US  levels and assuming China is able to sustain a 2.75% growth rate way out into the future (which is unlikely) and US incomes grow at 1% per year, it will take the better part of a century for China to match US living standards.

Worse still, the US Administration appears to have no concept of the gains from trade. As The Economist put it a few weeks ago, “Trump appears to see the world as he saw the New York property market, a place of screw or be screwed.” China may be stealing US technology and engaging in sharp practices to ensure that the playing field in the Chinese market is far from level, but that does not mean that the US should cut off its own nose to spite its face. Adam Smith – a hero of many on the right – argued in his 1776 publication The Wealth of Nations that all nations would gain simultaneously if they practiced free trade and specialized in accordance with their absolute advantage.

The US may no longer be the world’s primary producer of traditional industrial products such as steel, but it is still the world’s most technically advanced nation which in the past 20 years has given us Facebook, Amazon, Netflix and Google (the so-called FANGs) which also happen to be the largest global companies by market cap. Moreover, many companies rely on outsourcing production to external markets, and retaliation in response to US actions would imperil global value chains and force a rethink of how companies operate across borders with unanticipated consequences.

But rationality is not the order of the day. Western historians will probably look back at the first two decades of the 21st century as a golden period punctuated by a severe crisis that prompted irrational policy choices. They do say that you don’t know what you’ve lost until it’s gone. I miss the good old days even before they have ended.