The Output Gap is no longer a sufficient statistic for inflationary pressure

One of the features of the latest OBR forecast is that they believe the economy is operating slightly above its sustainable level (a positive output gap), where the sustainable level is the level that would keep inflation constant. To see how startling that hypothesis is, here is the latest version of a chart I have probably posted more than any other since I started writing this blog.

It is UK GDP per head (source), which is a pretty good measure of average prosperity, and a trend line in red for 2.23% growth p.a. So from 1955 to 2007 prosperity grew at an average rate of almost two and a quarter percent each year. Since then it has increased at an annual rate of around 0.35%. And if the OBR are right, none of this is due to unutilised resources and lack of demand.

The shift in trend is just as clear if we look at output per worker. Some people try and rationalise this by saying that 2007 was a boom year, and so trend growth had really been falling long before the Global Financial Crisis (GFC). But the evidence does not support more than a slight downward shift in the growth trend before the GFC: the OBR estimate an output gap of 0.7% in 2006/7 and 1.8% in 2007/8.

I find it extraordinary that most economists still talk about the output gap after the GFC in the same way that it was talked about before the crisis: as a limit to how far and fast the economy can expand. To do that is in my view quite wrong. It ignores what I call the innovations gap: the difference between actual output and the level of output that firms could achieve if they started using the best technology available to them. Because there is currently a large innovations gap, firms are likely to meet additional demand not be raising prices but by investing in these more efficient techniques.

Before the GFC, we could ignore the innovation gap because it was relatively small. But since the crisis that gap for the UK and many other countries must have increased, because it is simply not plausible to assume that since the GFC technical progress has come to a virtual halt. Innovations may not have been increasing at the pre-GFC rate, but they cannot have almost stopped, which is the implicit assumption in the OBR’s analysis. Hence we have in the UK, and I suspect in many other countries, a subsrantial innovations gap which will prevent any excess demand leading to significant inflationary pressure. Some supporting evidence for this comes from the growing productivity divergence between leading firms and the rest.

Why have most firms not been investing in the most productive equipment and techniques since the GFC? I think the simple answer is fixed costs and demand. Investment projects almost always involve a large fixed cost element (disruption, retraining), and with static demand those fixed costs may exceed any efficiency gain. But in a normal recovery from a recession, where demand is growing rapidly, firms are happy to incur that fixed cost because they need to expand capacity anyway to meet growing demand. In a weak recovery, on the other hand, many firms may not need to expand capacity, with any modest increases in demand going to leading firms, firms that do invest in the latest technology. Hence the divergence noted above.

Exactly the same argument applies to the NAIRU: the level of unemployment at which inflation is constant. The NAIRU is almost certainly lower than most central banks think for a variety of reasons, but when it is approached I expected to see a pick up in investment and innovation more than a pick up in wage inflation. Investment and productivity growth go together, as a nice chart in the OBR’s latest forecast report shows (page 43).

A large innovation gap in the UK is being enhanced by Brexit. The more uncertain future demand is the more firms are likely to postpone productivity enhancing investment. It may be politically useful to delay creating a new customs union/SM for goods with the EU to try and keep the Conservative party together (as regular readers will know, I think this is inevitable because of the Irish border), but the uncertainty that delay creates just holds back UK growth. Just one more way in which both Brexit and more generally a Conservative government is an economically destructive project.

The existence of a large innovations gap, both in the UK and elsewhere, means that we need two things. First, we need a monetary policy that is very relaxed about raising interest rates. Second we need, in the UK and pretty well everywhere, a large increase in public sector investment. The first needs independent central banks to be less inflation averse and to stop treating the sustainable level of output as something which is independent of what they do. The second requires governments to stop being obsessed about deficits and instead to start investing in the future of all the people they govern.