Archive for the 'natural rate of unemployment' Category

Richard Lipsey and the Phillips Curve Redux

Almost three and a half years ago, I published a post about Richard Lipsey’s paper “The Phillips Curve and the Tyranny of an Assumed Unique Macro Equilibrium.” The paper originally presented at the 2013 meeting of the History of Econmics Society has just been published in the Journal of the History of Economic Thought, with a slightly revised title “The Phillips Curve and an Assumed Unique Macroeconomic Equilibrium in Historical Context.” The abstract of the revised published version of the paper is different from the earlier abstract included in my 2013 post. Here is the new abstract.

An early post-WWII debate concerned the most desirable demand and inflationary pressures at which to run the economy. Context was provided by Keynesian theory devoid of a full employment equilibrium and containing its mainly forgotten, but still relevant, microeconomic underpinnings. A major input came with the estimates provided by the original Phillips curve. The debate seemed to be rendered obsolete by the curve’s expectations-augmented version with its natural rate of unemployment, and associated unique equilibrium GDP, as the only values consistent with stable inflation. The current behavior of economies with the successful inflation targeting is inconsistent with this natural-rate view, but is consistent with evolutionary theory in which economies have a wide range of GDP-compatible stable inflation. Now the early post-WWII debates are seen not to be as misguided as they appeared to be when economists came to accept the assumptions implicit in the expectations-augmented Phillips curve.

Publication of Lipsey’s article nicely coincides with Roger Farmer’s new book Prosperity for All which I discussed in my previous post. A key point that Roger makes is that the assumption of a unique equilibrium which underlies modern macroeconomics and the vertical long-run Phillips Curve is neither theoretically compelling nor consistent with the empirical evidence. Lipsey’s article powerfully reinforces those arguments. Access to Lipsey’s article is gated on the JHET website, so in addition to the abstract, I will quote the introduction and a couple of paragraphs from the conclusion.

One important early post-WWII debate, which took place particularly in the UK, concerned the demand and inflationary pressures at which it was best to run the economy. The context for this debate was provided by early Keynesian theory with its absence of a unique full-employment equilibrium and its mainly forgotten, but still relevant, microeconomic underpinnings. The original Phillips Curve was highly relevant to this debate. All this changed, however, with the introduction of the expectations-augmented version of the curve with its natural rate of unemployment, and associated unique equilibrium GDP, as the only values consistent with a stable inflation rate. This new view of the economy found easy acceptance partly because most economists seem to feel deeply in their guts — and their training predisposes them to do so — that the economy must have a unique equilibrium to which market forces inevitably propel it, even if the approach is sometimes, as some believe, painfully slow.

The current behavior of economies with successful inflation targeting is inconsistent with the existence of a unique non-accelerating-inflation rate of unemployment (NAIRU) but is consistent with evolutionary theory in which the economy is constantly evolving in the face of path-dependent, endogenously generated, technological change, and has a wide range of unemployment and GDP over which the inflation rate is stable. This view explains what otherwise seems mysterious in the recent experience of many economies and makes the early post-WWII debates not seem as silly as they appeared to be when economists came to accept the assumption of a perfectly inelastic, long-run Phillips curve located at the unique equilibrium level of unemployment. One thing that stands in the way of accepting this view, however, the tyranny of the generally accepted assumption of a unique, self-sustaining macroeconomic equilibrium.

This paper covers some of the key events in the theory concerning, and the experience of, the economy’s behavior with respect to inflation and unemployment over the post-WWII period. The stage is set by the pressure-of-demand debate in the 1950s and the place that the simple Phillips curve came to play in it. The action begins with the introduction of the expectations-augmented Phillips curve and the acceptance by most Keynesians of its implication of a unique, self-sustaining macro equilibrium. This view seemed not inconsistent with the facts of inflation and unemployment until the mid-1990s, when the successful adoption of inflation targeting made it inconsistent with the facts. An alternative view is proposed, on that is capable of explaining current macro behavior and reinstates the relevance of the early pressure-of-demand debate. (pp. 415-16).

In reviewing the evidence that stable inflation is consistent with a range of unemployment rates, Lipsey generalizes the concept of a unique NAIRU to a non-accelerating-inflation band of unemployment (NAIBU) within which multiple rates of unemployment are consistent with a basically stable expected rate of inflation. In an interesting footnote, Lipsey addresses a possible argument against the relevance of the empirical evidence for policy makers based on the Lucas critique.

Some might raise the Lucas critique here, arguing that one finds the NAIBU in the data because policymakers are credibly concerned only with inflation. As soon as policymakers made use of the NAIBU, the whole unemployment-inflation relation that has been seen since the mid-1990s might change or break. For example, unions, particularly in the European Union, where they are typically more powerful than in North America, might alter their behavior once they became aware that the central bank was actually targeting employment levels directly and appeared to have the power to do so. If so, the Bank would have to establish that its priorities were lexicographically ordered with control of inflation paramount so that any level-of-activity target would be quickly dropped whenever inflation threatened to go outside of the target bands. (pp. 426-27)

I would just mention in this context that in this 2013 post about the Lucas critique, I pointed out that in the paper in which Lucas articulated his critique, he assumed that the only possible source of disequilibrium was a mistake in expected inflation. If everything else is working well, causing inflation expectations to be incorrect will make things worse. But if there are other sources of disequilibrium, it is not clear that incorrect inflation expectations will make things worse; they could make things better. That is a point that Lipsey and Kelvin Lancaster taught the profession in a classic article “The General Theory of Second Best,” 20 years before Lucas published his critique of econometric policy evaluation.

I conclude by quoting Lipsey’s penultimate paragraph (the final paragraph being a quote from Lipsey’s paper on the Phillips Curve from the Blaug and Lloyd volume Famous Figures and Diagrams in Economics which I quoted in full in my 2013 post.

So we seem to have gone full circle from the early Keynesian view in which there was no unique level of GDP to which the economy was inevitably drawn, through a simple Phillips curve with its implied trade-0ff, to an expectations-augmented Phillips curve (or any of its more modern equivalents) with its associated unique level of GDP, and finally back to the early Keynesian view in which policymakers had an option as to the average pressure of aggregate demand at which economic activity could be sustained. However, the modern debated about whether to aim for [the high or low range of stable unemployment rates] is not a debate about inflation versus growth, as it was in the 1950s, but between those who would risk an occasional rise of inflation above the target band as the price of getting unemployment as low as possible and those who would risk letting unemployment fall below that indicated by the lower boundary of the NAIBU  as the price of never risking an acceleration of inflation above the target rate. (p. 427)

Making Sense of the Phillips Curve

In a comment on my previous post about supposedly vertical long run Phillips Curve, Richard Lipsey mentioned a paper he presented a couple of years ago at the History of Economics Society Meeting: “The Phillips Curve and the Tyranny of an Assumed Unique Macro Equilibrium.” In a subsequent comment, Richard also posted the abstract to his paper. The paper provides a succinct yet fascinating overview of the evolution macroeconomists’ interpretations of the Phillips curve since Phillips published his paper almost 60 years ago.

The two key points that I take away from Richard’s discussion are the following. 1) A key microeconomic assumption underlying the Keynesian model is that over a broad range of outputs, most firms are operating under conditions of constant short-run marginal cost, because in the short run firms keep the capital labor ratio fixed, varying their usage of capital along with the amount of labor utilized. With a fixed capital-labor ration, marginal cost is flat. In the usual textbook version, the short-run marginal cost is rising because of a declining capital-labor ratio, requiring an increasing number of workers to wring out successive equal increments of output from a fixed amount of capital. Given flat marginal cost, firms respond to changes in demand by varying output but not price until they hit a capacity bottleneck.

The second point, a straightforward implication of the first, is that there are multiple equilibria for such an economy, each equilibrium corresponding to a different level of total demand, with a price level more or less determined by costs, at any rate until total output approaches the limits of its capacity.

Thus, early on, the Phillips Curve was thought to be relatively flat, with little effect on inflation unless unemployment was forced down below some very low level. The key question was how far unemployment could be pushed down before significant inflationary pressure would begin to emerge. Doctrinaire Keynesians advocated driving unemployment down as low as possible, while skeptics argued that significant inflationary pressure would begin to emerge even at higher rates of unemployment, so that a prudent policy would be to operate at a level of unemployment sufficiently high to keep inflationary pressures in check.

Lipsey allows that, in the 1960s, the view that the Phillips Curve presented a menu of alternative combinations of unemployment and inflation from which policymakers could choose did take hold, acknowledging that he himself expressed such a view in a 1965 paper (“Structural and Deficient Demand Unemployment Reconsidered” in Employment Policy and the Labor Market edited by Arthur Ross), “inflationary points on the Phillips Curve represent[ing] disequilibrium points that had to be maintained by monetary policy that perpetuated the disequilibrium by suitable increases in the rate of monetary expansion.” It was this version of the Phillips Curve that was effectively attacked by Friedman and Phelps, who replaced it with a version in which the equilibrium rate of unemployment is uniquely determined by real factors, the natural rate of unemployment, any deviation from the natural rate resulting in a series of adjustments in inflation and expected inflation that would restore the natural rate of unemployment.

Sometime in the 1960s the Phillips curve came to be thought of as providing a stable trade-off between inflation and unemployment. When Lipsey did adopt this trade-off version, as for example Lipsey (1965), inflationary points on the Phillips curve represented disequilibrium points that had to be maintained by monetary policy that perpetuated the disequilibrium by suitable increases in the rate of monetary expansion. In the new Classical interpretation that began with Edmund Phelps (1967), Milton Friedman (1968) and Lucas and Rapping (1969), each point was an equilibrium point because demands and supplies of agents were shifted from their full-information locations when they misinterpreted the price signals. There was, however, only one full-information equilibrium of income, Y*, and unemployment, U*.

The Friedman-Phelps argument was made as inflation rose significantly in the late 1960s, and the mild 1969-70 recession reduce inflation by only a smidgen, setting the stage for Nixon’s imposition of his disastrous wage and price controls in 1971 combined with a loosening of monetary policy by a compliant Arthur Burns as part of Nixon’s 1972 reelection strategy. When the hangover to the 1972 monetary binge was combined with a quadrupling of oil prices by OPEC in late 1973, the result was a simultaneous increase in inflation and unemployment – stagflation — a combination widely perceived as a decisive refutation of Keynesian theory. To cope with that theoretical conundrum, the Keynesian model was expanded to incorporate the determination of the price level by deriving an aggregate supply and aggregate demand curve in price-level/output space.

Lipsey acknowledges a crucial misstep in constructing the Aggregate Demand/Aggregate Supply framework: assuming a unique macroeconomic equilibrium, an assumption that implied the existence of a unique natural rate of unemployment. Keynesians won the battle, providing a perfectly respectable theoretical explanation for stagflation, but, in doing so, they lost the war to Friedman, paving the way for the malign ascendancy of New Classical economics, with which New Keynesian economics became an effective collaborator. Whether the collaboration was willing or unwilling is unclear and unimportant; by assuming a unique equilibrium, New Keynesians gave up the game.

I was so intent in showing that this AD-AS construction provided a simple Keynesian explanation of stagflation, contrary to the accusation of the New Classical economists that stagflation provided a conclusive refutation of Keynesian economics that I paid too little attention to the enormous importance of the new assumption introduced into Keynesian models. The addition of an expectations-augmented Philips curve, negatively sloped in the short run but vertical in the long run, produced a unique macro equilibrium that would be reached whatever macroeconomic policy was adopted.

Lipsey does not want to go back to the old Keynesian paradigm; he prefers a third approach that can be traced back to, among others, Joseph Schumpeter in which the economy is viewed “as constantly evolving under the impact of endogenously generated technological change.” Such technological change can be vaguely foreseen, but also gives rise to genuine surprises. The course of economic development is not predetermined, but path-dependent. History matters.

I suggest that the explanation of the current behaviour of inflation, output and unemployment in modern industrial economies is provided not by any EWD [equilibrium with deviations] theory but by evolutionary theories. These build on the obvious observation that technological change is continual in modern economies (decade by decade at least since 1760), but uneven (tending to come in spurts), and path dependent (because, among other reasons, knowledge is cumulative with one advance enabling another). These changes are generated endogenously by private-sector, profit-seeking agents competing in terms of new products, new processes and new forms of organisation, and by public sector activities in such places as universities and government research laboratories. They continually alter the structure of the economy, causing waves of serially correlated investment expenditure that are a major cause of cycles, as well as driving the long-term growth that continually transforms our economic, social and political structures. In their important book As Time Goes By, Freeman and Louça (2001) trace these processes as they have operated since the beginnings of the First Industrial Revolution.

A critical distinction in all such theories is between risk, which is easily handled in neoclassical economics, and uncertainty, which is largely ignored in it except to pay it lip service. In risky situations, agents with the same objective function and identical knowledge will chose the same alternative: the one that maximizes the expected value of their profits or utility. This gives rise to unique predictable behaviour of agents acting under specified conditions. In contrast in uncertain situations, two identically situated and motivated agents can, and observably do, choose different alternatives — as for example when different firms all looking for the same technological breakthrough chose different lines of R&D — and there is no way to tell in advance of knowing the results which is the better choice. Importantly, agents typically make R&D decisions under conditions of genuine uncertainty. No one knows if a direction of technological investigation will go up a blind alley or open onto a rich field of applications until funds are spend investigating the route. Sometimes trivial expenses produce results of great value while major expenses produce nothing of value. Since there is no way to decide in advance which of two alternative actions with respect to invention or innovation is the best one until the results are known, there is no unique line of behaviour that maximises agents’ expected profits. Thus agents are better understood as groping into an uncertain future in a purposeful, profit- or utility-seeking manner, rather than as maximizing their profits or utility.

This is certainly the right way to think about how economies evolve over time, but I would just add that even if one stays within the more restricted framework of Walrasian general equilibrium, there is simply no persuasive theoretical reason to assume that there is a unique equilibrium or that an economy will necessarily arrive at that equilibrium no matter how long we wait. I have discussed this point several times before most recently here. The assumption that there is a natural rate of unemployment “ground out,” as Milton Friedman put it so awkwardly, “by the Walrasian system of general equilibrium equations” simply lacks any theoretical foundation. Even in a static model in which knowledge and technology were not evolving, the natural rate of unemployment is a will o the wisp.

Because there is no unique static equilibrium in the evolutionary world in which history matters, no adjustment mechanism is required to maintain it. Instead, the constantly changing economy can exist over a wide range of income, employment and unemployment values, without behaving as it would if its inflation rate were determined by an expectations-augmented Phillips curve or any similar construct centred on unique general equilibrium values of Y and U. Thus there is no stable long-run vertical Phillips curve or aggregate supply curve.

Instead of the Phillips curve there is a band as shown in Figure 4 [See below]. Its midpoint is at the expected rate of inflation. If the central bank has a credible inflation target that it sticks to, the expected rate will be that target rate, shown as πe in the figure. The actual rate will vary around the expected rate depending on a number of influences such as changes in productivity, the price of oil and food, but not significantly on variations in U or Y. At either end of this band, there may be something closer to a conventional Phillips curve with prices and wages falling in the face of a major depression and rising in the face of a major boom financed by monetary expansion. Also, the whole band will be shifted by anything that changes the expected rate of inflation.


Lipsey concludes as follows:

So we seem to have gone full circle from early Keynesian view in which there was no unique level of income to which the economy was inevitably drawn, through a simple Phillips curve with its implied trade off, to an expectations-augmented Phillips curve (or any of its more modern equivalents) with its associated unique level of national income, and finally back to the early non-unique Keynesian view in which policy makers had an option as to the average pressure of aggregate demand at which the economy could be operated.

“Perhaps [then] Keynesians were too hasty in following the New Classical economists in accepting the view that follows from static [and all EWD] models that stable rates of wage and price inflation are poised on the razor’s edge of a unique NAIRU and its accompanying Y*. The alternative does not require a long term Phillips curve trade off, nor does it deny the possibility of accelerating inflations of the kind that have bedevilled many third world countries. It is merely states that industrialised economies with low expected inflation rates may be less precisely responsive than current theory assumes because they are subject to many lags and inertias, and are operating in an ever-changing and uncertain world of endogenous technological change, which has no unique long term static equilibrium. If so, the economy may not be similar to the smoothly functioning mechanical world of Newtonian mechanics but rather to the imperfectly evolving world of evolutionary biology. The Phillips relation then changes from being a precise curve to being a band within which various combinations of inflation and unemployment are possible but outside of which inflation tends to accelerate or decelerate. Perhaps then the great [pre-Phillips curve] debates of the 1940s and early 1950s that assumed that there was a range within which the economy could be run with varying pressures of demand, and varying amounts of unemployment and inflation[ary pressure], were not as silly as they were made to seem when both Keynesian and New Classical economists accepted the assumption of a perfectly inelastic, one-dimensional, long run Phillips curve located at a unique equilibrium Y* and NAIRU.” (Lipsey, “The Phillips Curve,” In Famous Figures and Diagrams in Economics, edited by Mark Blaug and Peter Lloyd, p. 389)

Who Sets the Real Rate of Interest?

Understanding economics requires, among other things, understanding the distinction between real and nominal variables. Confusion between real and nominal variables is pervasive, constantly presenting barriers to clear thinking, and snares and delusions for the mentally lazy. In this post, I want to talk about the distinction between the real rate of interest and the nominal rate of interest. That distinction has been recognized for at least a couple of centuries, Henry Thornton having mentioned it early in the nineteenth century. But the importance of the distinction wasn’t really fully understood until Irving Fisher made the distinction between the real and nominal rates of interest a key element of his theory of interest and his theory of money, expressing the relationship in algebraic form — what we now call the Fisher equation. Notation varies, but the Fisher equation can be written more or less as follows:

i = r + dP/dt,

where i is the nominal rate, r is the real rate, and dP/dt is the rate of inflation. It is important to bear in mind that the Fisher equation can be understood in two very different ways. It can either represent an ex ante relationship, with dP/dt referring to expected inflation, or it can represent an ex post relationship, with dP/dt referring to actual inflation.

What I want to discuss in this post is the tacit assumption that usually underlies our understanding, and our application, of the ex ante version of the Fisher equation. There are three distinct variables in the Fisher equation: the real and the nominal rates of interest and the rate of inflation. If we think of the Fisher equation as an ex post relationship, it holds identically, because the unobservable ex post real rate is defined as the difference between the nominal rate and the inflation rate. The ex post, or the realized, real rate has no independent existence; it is merely a semantic convention. But if we consider the more interesting interpretation of the Fisher equation as an ex ante relationship, the real interest rate, though still unobservable, is not just a semantic convention. It becomes the theoretically fundamental interest rate of capital theory — the market rate of intertemporal exchange, reflecting, as Fisher masterfully explained in his canonical renderings of the theory of capital and interest, the “fundamental” forces of time preference and the productivity of capital. Because it is determined by economic “fundamentals,” economists of a certain mindset naturally assume that the real interest rate is independent of monetary forces, except insofar as monetary factors are incorporated in inflation expectations. But if money is neutral, at least in the long run, then the real rate has to be independent of monetary factors, at least in the long run. So in most expositions of the Fisher equation, it is tacitly assumed that the real rate can be treated as a parameter determined, outside the model, by the “fundamentals.” With r determined exogenously, fluctuations in i are correlated with, and reflect, changes in expected inflation.

Now there’s an obvious problem with the Fisher equation, which is that in many, if not most, monetary models, going back to Thornton and Wicksell in the nineteenth century, and to Hawtrey and Keynes in the twentieth, and in today’s modern New Keynesian models, it is precisely by way of changes in its lending rate to the banking system that the central bank controls the rate of inflation. And in this framework, the nominal interest rate is negatively correlated with inflation, not positively correlated, as implied by the usual understanding of the Fisher equation. Raising the nominal interest rate reduces inflation, and reducing the nominal interest rate raises inflation. The conventional resolution of this anomaly is that the change in the nominal interest rate is just temporary, so that, after the economy adjusts to the policy of the central bank, the nominal interest rate also adjusts to a level consistent with the exogenous real rate and to the rate of inflation implied by the policy of the central bank. The Fisher equation is thus an equilibrium relationship, while central-bank policy operates by creating a short-term disequilibrium. But the short-term disequilibrium imposed by the central bank cannot be sustained, because the economy inevitably begins an adjustment process that restores the equilibrium real interest rate, a rate determined by fundamental forces that eventually override any nominal interest rate set by the central bank if that rate is inconsistent with the equilibrium real interest rate and the expected rate of inflation.

It was just this analogy between the powerlessness of the central bank to hold the nominal interest rate below the sum of the exogenously determined equilibrium real rate and the expected rate of inflation that led Milton Friedman to the idea of a “natural rate of unemployment” when he argued that monetary policy could not keep the unemployment rate below the “natural rate ground out by the Walrasian system of general equilibrium equations.” Having been used by Wicksell as a synonym for the Fisherian equilibrium real rate, the term “natural rate” was undoubtedly adopted by Friedman, because monetarily induced deviations between the actual rate of unemployment and the natural rate of unemployment set in motion an adjustment process that restores unemployment to its “natural” level, just as any deviation between the nominal interest rate and the sum of the equilibrium real rate and expected inflation triggers an adjustment process that restores equality between the nominal rate and the sum of the equilibrium real rate and expected inflation.

So, if the ability of the central bank to use its power over the nominal rate to control the real rate of interest is as limited as the conventional interpretation of the Fisher equation suggests, here’s my question: When critics of monetary stimulus accuse the Fed of rigging interest rates, using the Fed’s power to keep interest rates “artificially low,” taking bread out of the mouths of widows, orphans and millionaires, what exactly are they talking about? The Fed has no legal power to set interest rates; it can only announce what interest rate it will lend at, and it can buy and sell assets in the market. It has an advantage because it can create the money with which to buy assets. But if you believe that the Fed cannot reduce the rate of unemployment below the “natural rate of unemployment” by printing money, why would you believe that the Fed can reduce the real rate of interest below the “natural rate of interest” by printing money? Martin Feldstein and the Wall Street Journal believe that the Fed is unable to do one, but perfectly able to do the other. Sorry, but I just don’t get it.

Look at the accompanying chart. It tracks the three variables in the Fisher equation (the nominal interest rate, the real interest rate, and expected inflation) from October 1, 2007 to July 2, 2013. To measure the nominal interest rate, I use the yield on 10-year Treasury bonds; to measure the real interest rate, I use the yield on 10-year TIPS; to measure expected inflation, I use the 10-year breakeven TIPS spread. The yield on the 10-year TIPS is an imperfect measure of the real rate, and the 10-year TIPS spread is an imperfect measure of inflation expectations, especially during financial crises, when the rates on TIPS are distorted by illiquidity in the TIPS market. Those aren’t the only problems with identifying the TIPS yield with the real rate and the TIPS spread with inflation expectations, but those variables usually do provide a decent approximation of what is happening to real rates and to inflation expectations over time.


Before getting to the main point, I want to make a couple of preliminary observations about the behavior of the real rate over time. First, notice that the real rate declined steadily, with a few small blips, from October 2007 to March 2008, when the Fed was reducing the Fed Funds target rate from 4.75 to 3% as the economy was sliding into a recession that officially began in December 2007. The Fed reduced the Fed Funds target to 2% at the end of April, but real interest rates had already started climbing in early March, so the failure of the FOMC to reduce the Fed Funds target again till October 2008, three weeks after the onset of the financial crisis, clearly meant that there was at least a passive tightening of monetary policy throughout the second and third quarters, helping create the conditions that precipitated the crisis in September. The rapid reduction in the Fed Funds target from 2% in October to 0.25% in December 2008 brought real interest rates down, but, despite the low Fed Funds rate, a lack of liquidity caused a severe tightening of monetary conditions in early 2009, forcing real interest rates to rise sharply until the Fed announced its first QE program in March 2009.

I won’t go into more detail about ups and downs in the real rate since March 2009. Let’s just focus on the overall trend. From that time forward, what we see is a steady decline in real interest rates from over 2% at the start of the initial QE program till real rates bottomed out in early 2012 at just over -1%. So, over a period of three years, there was a steady 3% decline in real interest rates. This was no temporary phenomenon; it was a sustained trend. I have yet to hear anyone explain how the Fed could have single-handedly produced a steady downward trend in real interest rates by way of monetary expansion over a period of three years. To claim that decline in real interest rates was caused by monetary expansion on the part of the Fed flatly contradicts everything that we think we know about the determination of real interest rates. Maybe what we think we know is all wrong. But if it is, people who blame the Fed for a three-year decline in real interest rates that few reputable economists – and certainly no economists that Fed critics pay any attention to — ever thought was achievable by monetary policy ought to provide an explanation for how the Fed suddenly got new and unimagined powers to determine real interest rates. Until they come forward with such an explanation, Fed critics have a major credibility problem.

So please – pleaseWall Street Journal editorial page, Martin Feldstein, John Taylor, et al., enlighten us. We’re waiting.

PS Of course, there is a perfectly obvious explanation for the three-year long decline in real interest rates, but not one very attractive to critics of QE. Either the equilibrium real interest rate has been falling since 2009, or the equilibrium real interest rate fell before 2009, but nominal rates adjusted slowly to the reduced real rate. The real interest rate might have adjusted more rapidly to the reduced equilibrium rate, but that would have required expected inflation to have risen. What that means is that sometimes it is the real interest rate, not, as is usually assumed, the nominal rate, that adjusts to the expected rate of inflation. My next post will discuss that alternative understanding of the implicit dynamics of the Fisher equation.

Why Are Real Interest Rates So Low, and Will They Ever Bounce Back?

In his recent post commenting on the op-ed piece in the Wall Street Journal by Michael Woodford and Frederic Mishkin on nominal GDP level targeting (hereinafter NGDPLT), Scott Sumner made the following observation.

I would add that Woodford’s preferred interest rate policy instrument is also obsolete.  In the next recession, and probably the one after that, interest rates will again fall to zero.  Indeed the only real suspense is whether they’ll be able to rise significantly above zero before the next recession hits.  In the US in 1937, Japan in 2001, and the eurozone in 2011, rates had barely nudged above zero before the next recession hit. Ryan Avent has an excellent post discussing this issue.

Perhaps I am misinterpreting him, but Scott seems to think that the decline in real interest rates reflects some fundamental change in the economy since approximately the start of the 21st century. Current low real rates, below zero on US Treasuries well up the yield curve. The real rate is unobservable, but it is related to (but not identical with) the yield on TIPS which are now negative up to 10-year maturities. The fall in real rates partly reflects the cyclical tendency for the expected rate of return on new investment to fall in recessions, but real interest rates were falling even before the downturn started in 2007.

In this post, at any rate, Scott doesn’t explain why the real rate of return on investment is falling. In the General Theory, Keynes speculated about the possibility that after the great industrialization of the 19th and early 20th centuries, new opportunities for investment were becoming exhausted. Alvin Hansen, an early American convert to Keynesianism, developed this idea into what he called the secular-stagnation hypothesis, a hypothesis suggesting that, after World War II, even with very low interest rates, the US economy was likely to relapse into depression. The postwar boom seemed to disprove Hansen’s idea, which became a kind of historical curiosity, if not an embarrassment. I wonder if Scott thinks that Keynes and Hansen were just about a half-century ahead of their time, or does he have some other reason in mind for why he thinks that real interest rates are destined to be very low?

One possibility, which, in a sense, is the optimistic take on our current predicament, is that low real interest rates are the result of bad monetary policy, the obstacle to an economic expansion that, in the usual course of events, would raise real interest rates back to more “normal” levels. There are two problems with this interpretation. First, the decline in real interest rates began in the last decade well before the 2007-09 downturn. Second, why does Scott, evidently accepting Ryan Avent’s pessimistic assessment of the life-expectancy of the current recovery notwithstanding rapidly increasing support for NGDPLT, anticipate a relapse into recession before the recovery raises real interest rates above their current near-zero levels? Whatever the explanation, I look forward to hearing more from Scott about all this.

But in the meantime, here are some thoughts of my own about our low real interest rates.

First, it can’t be emphasized too strongly that low real interest rates are not caused by Fed “intervention” in the market. The Fed can buy up all the Treasuries it wants to, but doing so could not force down interest rates if those low interest rates were inconsistent with expected rates of return on investment and the marginal rate of time preference of households. Despite low real interest rates, consumers are not rushing to borrow money at low rates to increase present consumption, nor are businesses rushing to take advantage of low real interest rates to undertake shiny new investment projects. Current low interest rates are a reflection of the expectations of the public about their opportunities for trade-offs between current and future consumption and between current and future production and their expectations about future price levels and interest rates. It is not the Fed that is punishing savers, as the editorial page of the Wall Street Journal constantly alleges. Rather, it is the distilled wisdom of market participants that is determining how much any individual should be rewarded for the act of abstaining from current consumption. Unfortunately, there is so little demand for resources to be used to increase future output, the act of abstaining from current consumption contributes essentially nothing, at the margin, to the increase of future output, which is why the market is now offering next to no reward for a marginal abstention from current consumption.

Second, interest rates reflect the expectations of businesses and investors about the profitability of investing in new capital, and the expectations of households about their future incomes (largely dependent on expectations about future employment). These expectations – about profitability and about future incomes — are distinct, but they are clearly interdependent. If businesses are optimistic about the profitability of future investment, households are likely to be optimistic about future incomes. If households are pessimistic about future incomes, businesses are unlikely to expect investments in new capital to be profitable. If real interest rates are stuck at zero, it suggests that businesses and households are stuck in a mutually reinforcing cycle of pessimistic expectations — households about future income and employment and businesses about the profitability of investing in new capital. Expectations, as I have said before, are fundamental. Low interest rates and secular stagnation need not be the result of an inevitable drying up of investment opportunities; they may be the result of a vicious cycle of mutually reinforcing pessimism by households and businesses.

The simple Keynesian model — at least the Keynesian-cross version of intro textbooks or even the IS-LM version of intermediate textbooks – generally holds expectations constant. But in fact, it is through the adjustment of expectations that full-employment equilibrium is reached. For fiscal or monetary policy to work, they must alter expectations. Conventional calculations of spending or tax multipliers, which implicitly hold expectations constant, miss the point, which is to alter expectations.

Similarly, as I have tried to suggest in my previous two posts, what Friedman called the natural rate of unemployment may itself depend on expectations. A change in monetary policy may alter expectations in a manner that reduces the natural rate. A straightforward application of the natural-rate model leads some to dismiss a reduction in unemployment associated with a small increase in the rate of inflation as inefficient, because the increase in employment results from workers being misled into accepting jobs that will turn out to pay workers a lower real wage than they had expected. But even if that is so, the increase in employment may still be welfare-increasing, because the employment of each worker improves the chances that another worker will become employed. The social benefit of employment may be greater than the private benefit. In that case, the apparent anomaly (from the standpoint of the natural-rate hypothesis) that measurements of social well-being seem to be greatest when employment is maximized actually make perfectly good sense.

In an upcoming post, I hope to explore some other possible explanations for low real interest rates.

About Me

David Glasner
Washington, DC

I am an economist in the Washington DC area. My research and writing has been mostly on monetary economics and policy and the history of economics. In my book Free Banking and Monetary Reform, I argued for a non-Monetarist non-Keynesian approach to monetary policy, based on a theory of a competitive supply of money. Over the years, I have become increasingly impressed by the similarities between my approach and that of R. G. Hawtrey and hope to bring Hawtrey's unduly neglected contributions to the attention of a wider audience.

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