What is secular stagnation? Apparently it's frequently on the lips of some people, but according to Barry Eichengreen,
...while the term ‘secular stagnation’ was widely repeated, it was not widely understood. Secular stagnation, we have learned, is an economist’s Rorchach Test. It means different things to different people.I think the problem here is that an idea cannot be understood if it's not an idea. The people who claim that the idea exists - principally Larry Summers and Paul Krugman - trace it to Alvin Hansen's "Economic Progress and Declining Population Growth," from 1939. Nicholas Crafts summarizes what Hansen had to say:
The first time around, ‘secular stagnation’ was a hypothesis famously articulated by Alvin Hansen ... Hansen argued that the US economy faced a crisis of underinvestment and deficient aggregate demand, since investment opportunities had significantly diminished in the face of the closing of the frontier for new waves of immigration and declining population growth. It was as if the US was faced with a lower natural rate of growth to which the rate of growth of the capital stock would adjust through a permanently lower rate of investment.I think we could go even further than that. Not only were Hansen's writings the "delusions of a hypochondriac," but we would have a hard time making sense of his arguments in the context of the modern theory of economic growth, and what we know about the causes of growth and the reasons for differences in standards of living across countries. Suffice to say that a re-reading of Alvin Hansen won't enlighten us as to what we should expect from the world economy over the next twenty years or so.
As we all know, these fears were completely without foundation – the delusions of a hypochondriac rather than the insightful diagnosis of a celebrated economist.
But, what about the contents of this ebook? There are really two parallel notions of stagnation discussed in these contributed papers. For convenience, I'll call these growth stagnation and Keynesian stagnation. The growth stagnation idea appears to take conventional economic growth theory as a basis for how we should think about future economic growth, in the U.S. and in the world. From Hsieh and Klenow, empirical work on economic growth tells us that we can account for 10-30% in income differences across countries by differences in human capital, about 20% by differences in physical capital, and 50-70% by differences in TFP (total factor productivity). This should also apply to the time series. So if, for example, we are pessimistic about future TFP growth in the U.S., we then have a strong reason to be pessimistic about future real GDP growth in the U.S. On one side of the argument, Robert Gordon is a pessimist. Gordon points out that TFP growth was much lower after 1970 than in the period from 1920-1970, and he is confident that the average rate of TFP growth we experienced for 1970-2014 will persist for the next 25-40 years. Further, he is worried about four "headwinds," i.e. demographics, education, inequality, and government debt. Basically, a smaller fraction of the U.S. population will be working, educational attainment in the U.S. has plateaued and the quality of U.S. education may be in decline, inequality in incomes has increased and may continue to do so, and there are reasons to think that government debt could increase relative to GDP.
If reading Gordon's entry in this volume is inclined to make you depressed, Joel Mokyr's piece is a great pick-me-up. He says:
There is nothing like a recession to throw economists into a despondent mood. Much as happened in the late 1930s, many of my colleagues seem to believe that ‘sad days are here again’. Economic growth as it was experienced by the world through much of the 20th century, they tell us, was a fleeting thing. Our children will be no richer than we are. Some of the best economists of our age, including Larry Summers, Paul Krugman, and my own colleague Robert J. Gordon, are joining the chorus of the doomsayers. It is said that we are faced by headwinds that inevitably will slow down growth and perhaps condemn us to secular stagnation. There is no denying that the population of the world is getting older, and that the fraction of people working (and supporting the aged) is falling everywhere except in Africa. The ‘big pushes’ driven by millions of married women taking jobs and the huge increase in college graduates that drove post 1945 growth were one-off boons, but they are no more. Growing inequality exacerbates demography. Slow growth is here to stay, say the secular stagnationists.So, we should stop moaning, and recognize that life is pretty good and likely to get much better.
What is wrong with this story? The one word answer is ‘technology’. The responsibility of economic historians is to remind the world what things were like before 1800. Growth was imperceptibly slow, and the vast bulk of the population was so poor that any disruption in food supply caused by a harvest failure could kill millions. Almost half the babies born died before reaching the age of five, and those who made it to adulthood were often stunted, ill, and illiterate. What changed this world was growth driven by technological progress. Starting in the late 18th century, innovations and advances in what was then called ‘the useful arts’ slowly began improving life, first in Britain, then in the rest of Europe, and eventually in much of the rest of the world. The story has been told many times over, but as Nobelist Robert Lucas once wrote, once you start thinking about it, it’s hard to think of anything else.
Mokyr's point is that there is much important scientific advance happening right under our noses, and that this new science will be applied in many ways that we might find hard to imagine from our 2014 viewpoint, just as Alexander Graham Bell would have a hard time imagining an I-phone. Further, the effects of current and future innovations on economic welfare may not be measured well. For example, information has become much more accessible in myriad ways that make us better off, but not all of that is captured in GDP.
Technological change does create economic problems that we need to deal with, though. It is now well-understood that an important factor in the increase in the dispersion in income in the U.S. in the last 30 years or more has been technological change. This change can bring huge rewards to innovators while depreciating particular types of human capital. For example, David Autor has written about the hollowing out of the skill-distribution because information technology makes middle-level skills obsolete. This then becomes a challenge for U.S. education. Indeed, better access to public education at all levels is a possible remedy for the income-distribution problem that Gordon seems to be concerned with.
In terms of the growth stagnation story, there is nothing in this volume that sheds new light on the growth process, and would permit us to confidently project stagnation in the medium to long term, in the U.S., or in the world. We know a lot about how TFP, human capital accumulation, and physical capital accumulation, work to produce growth in per capita incomes, but we perhaps know little about the actual process of innovation, and how to predict it.
The idea that seems to have spurred the publication of this volume, however, is not growth stagnation, but Keynesian stagnation. But Keynesian stagnation does not appear - at least to me - to be in the Keynesian tradition. Keynesians have been quite comfortable with the idea that mainstream growth theory could guide our thinking about "long-run" issues, while sticky-price and sticky-wage economics could guide our thinking about "short-run" issues. For example, Robert Solow provided us with the foundation for modern growth theory, but also wrote (with Paul Samuelson) a classic paper on how to exploit the Phillips curve tradeoff. Similarly, Mike Woodford took a several-generations-later version of Solow's growth model (with credit to Cass, Koopmans, Brock, Mirman, Kydland, and Prescott, along the way), put in some sticky prices and monetary policy, and convinced central bankers that it would be a good idea to use such a model to think about short-run monetary policy. New Keynesian models have the property that monetary policy is non-neutral in the short run, but the mechanics of the basic growth model take over in the long run.
This is definitely not what Larry Summers and Paul Krugman have in mind. Here's the basic hypothesis, as stated by Summers:
Unfortunately, almost all work in both the New Classical and New Keynesian traditions has focused on the second moment (the variance) of output and employment. This thinking presumes that, with or without policy intervention, the workings of the market will eventually restore full employment and eliminate output gaps. The only questions are about the volatility of output and employment around their normal levels. What has happened in the last few years suggests that the second moment is second-order relative to the first moment – the average level of output and employment through time.I'll take "New Classical and New Keynesian traditions" to be represented by the ideas of Mike Woodford - prices and/or wages are sticky in the short run, and in the long run the world works according to the Solow/Cass/Koopmans/Brock/Mirman/Kydland/Prescott growth model. But what Summers sees is a world that is not at "full employment" even in the long run. He doesn't say this, but presumably he thinks that price rigidity and/or wage rigidity can persist indefinitely.
So what's the problem? Summers points out that the real rate of interest has declined over time, and argues - in typical New Keynesian fashion - that this has created a zero-lower-bound problem. The actual real rate has fallen, but it should be lower than it is (the "natural rate" is lower than the actual real rate), but monetary policy cannot lower the real rate further, because the short-term nominal interest rate is at its lower bound of zero. Summers argues that this problem could persist long into the future. Stagnation is then essentially a nagging output gap, that monetary policy cannot correct in the "usual" fashion. Paul Krugman is basically on the same wavelength.
If you are a young macroeconomist, you might be thinking of Summers and Krugman as some creaky dinosaurs blowing hot air. Where is your model, Summers and Krugman, you might say. Well, Eggertsson and Mehrotra have fleshed out a theory that they think captures what Summers and Krugman are trying to get at. The Eggertsson and Mehrotra chapter in this volume is a summary of a formal academic paper that I discussed in this post. The gist of that blog post is that Eggertsson and Mehrotra - as with Eggertsson/Krugman, which is closely related - focus on the wrong problem. The key inefficiency in their model arises from a credit friction, but they are focusing their attention on the secondary zero-lower-bound inefficiency that the credit friction creates. Basically, the problem is insufficient government debt, and the solution is straightforward.
Now we are getting somewhere. The contribution in this volume from Cabellero and Farhi gives a nice synopsis of safe asset shortages and why such shortages produce the low real interest rates we have been observing. Before the financial crisis, high savings in the world combined with financial innovation created a high demand for safe assets - as stores of wealth, as collateral, and for exchange in asset markets. Governments can supply safe assets, but the private sector can also do it. So, if governments do not increase their outstanding debt in the face of an increased demand for safe assets, then the price of safe assets rises and real interest rates fall. This creates a profit opportunity for the creation of safe private assets. Indeed, asset-backed securities could perform such a role. But the financial crisis showed us that, in the face of poor regulation, the capacity of the private sector to produce safe assets can be limited. Further, when the private sector builds up a stock of "safe" assets which proves not be safe, the ensuing destruction and loss of trust can result in persistent inefficiencies.
The private sector is rebuilding its capacity to produce safe assets, but changes in private sector regulation are also serving to increase the demand for safe assets. For example, the liquidity coverage ratio included in Basel III banking regulation will create an additional demand for safe assets by commercial banks. Though there are things that central banks can do in the face of safe asset shortages (as I show here and here), a safe asset shortage is basically a fiscal problem. The safe asset shortage is reflected in binding financial constraints that imply the economy is non-Ricardian. Government debt matters, and an expansion in the stock of government debt can be welfare improving. Presumably this also implies a lower net cost of financing government projects, meaning that a safe asset shortage provides an opportunity for the government to finance education and infrastructure on the cheap. Note that we can come to that conclusion without ever invoking stickiness, multipliers, fallacy-of-this, or fallacy-of-that.
An interesting feature of this paper is that it captures some of Larry Summers's concerns about monetary policy and financial stability. In the model, when there is a shortage of safe assets, low real interest rates can create incentive problems in asset markets. Basically, creating safe private assets is profitable when the real interest rate is low, but misrepresenting unsafe assets as safe ones is potentially even more profitable. Conventional monetary easing acts to reduce the real interest rate, and therefore aggravates incentive problems. Indeed, if incentive problems are severe enough, a safe asset shortage induces a situation in which the central bank should not push the nominal interest rate to zero.
The editors of this volume, Coen Teulings and Richard Baldwin, seem convinced that the potential for secular stagnation, whatever it may be, requires some radical rethinking of policy approaches. I don't think so. While there is much we don't know about how economies work, and we continue to learn, normal economics is certainly not at a loss in dealing with the problems we face, or will face.