The IMF on Investment since 2008

Vox today has a useful piece by five IMF economists on the behavior of business investment during and since the Great Recession. [1] From my point of view, there are three important points here.

1. The most important difference between this cycle and previous ones is the larger fall and slower recovery of private investment. This has always been my view, and I think it's an especially important point for heterodox folks to take on board because there has been such (excessive, in my opinion) emphasis on the inequality-consumption link in explaining persistent demand weakness.

This relationship between output and investment is consistent with previous recessions: 

business investment has deviated little from what could be expected given the weakness in economic activity. In other words, firms have reacted to weak sales – both current and prospective – by reducing capital spending. Indeed, in surveys, businesses typically report lack of customer demand as the dominant challenge they face.

In other words, the old Keynesian "accelerator" story explains the bulk of the shortfall in investment since 2008.

2. Historically, deviations in output and investment has been persistent; there is no tendency for recessions to be followed by a return to the previous trend. 

The blue line shows the behavior of output and investment in recessions historically, relative to the pre-recession trend. Note that is no tendency for the gap to close, as much as six years after the previous peak.

The authors don't emphasize this point, but it is important. If we look at recessions across a range of industrialized countries, on average the output losses are permanent. There is no tendency for output to return to the pre-trend. If this is true, there's no basis for the conventional distinction between a demand-determined "short run" and a supply-determined "long run." There is just one dynamic process. Steve Fazzari has reached this same conclusion, as I've written about here. Roger Farmer has just posted an econometric demonstration that in the postwar US, output changes are persistent -- there is no tendency to return to a trend.

 3. There's no reason to think that the investment deficit is explained by financial constraints. I should say frankly that the paper didn't move my priors much at all on this point, but it's still interesting that that's what it says. By their estimates, firms in more "financially-dependent" sectors (this is a standard technique, but whatever) initially reduced investment more than firms in less financially-dependent sectors, but as of 2013 investment in both groups of firms were the same 40 percent below the pre-crisis trend. If you believe these results -- and again, I don't put much weight on them, except as an indicator of the IMF flavor of received opinion -- then while tighter credit may have helped trigger the crisis, it cannot explain the persistent weakness of demand. Or from a policy perspective -- and the authors do say this -- measures to improve access to credit are unlikely to achieve much, at least relative to measures to boost demand.

Investment by sector

So these are features it might be nice to incorporate into a macro model -- investment determined mainly by (changes in) current output; a single system of demand-based dynamics, as opposed to a short-run demand story and a long-run supply-based steady state growth path; a possibility of multiple equilibria, such that (let's say) a temporary interruption of credit flows can produce a persistent reduction in output.  On one level I don't especially trust these results. But on another level, I think they provide a good set of stylized facts that macro models should aspire to parsimoniously explain. 

[1] The European Vox, not the Klein-Yglesias one.


UPDATE: Krugman today points to the same work and also interprets it as support for an accelerator story.

New-Old Paper on the Balance of Payments

Four or five years ago, I wrote a paper arguing that the US current account deficit, far from being a cause of the crisis of 2008, was a stabilizing force in the world economy. I presented it at a conference and then set it aside. I recently reread it and I think the arguments hold up well. If anything the case that the US, as the center of the world financial system, ought to run large current account deficits indefinitely looks even stronger now, given the contrasting example of Germany's behavior in the European system.

I've put the paper up as a working paper at John Jay economics department site. Here's the abstract:

Persistent current account imbalances need not contribute to macroe- conomic instability, despite widespread claims to the contrary by both mainstream and Post Keynesian economists. On the contrary, in a world of large capital inflows, a high and stable level of world output is most likely when the countries with the least capacity to generate capital inflows normally run current account surpluses, while the countries with the greatest capacity to generate capital inflows (the US in particular) normally run current account deficits. An emphasis on varying balance of payments constraints is consistent with the larger Post Keynesian vision, which emphasizes money flows and claims are not simply passive reflections of “real” economic developments, but exercise an important influence in their own right. It is also consistent with Keynes’ own views. This perspective helps explain why the crisis of 2008 did not take the form of a fall in the dollar, and why reserve accumulation in East Asia successfully protected those countries from a repeat of the crisis of 1997. Given the weakness of the “automatic” mechanisms that are supposed to balance trade, income and financial flows, a reduction of the US current account deficit is likely to exacerbate, rather than ameliorate, global macroeconomic instability.

You can read the whole thing here.

Causes and Effects of Wage Growth

Over here, a huge stack of exams, sitting ungraded since… no, I can't say, it's too embarrassing.  There, a grant proposal that extensive experimentation has shown will not, in fact, write itself. And I still owe a response to all the responses and criticism to my Disgorge the Cash paper for Roosevelt. So naturally, I thought this morning would be a good time to sit down and ask what we can learn from comparing the path of labor costs in the Employment Cost Index compared with the ECEC.

The BLS explains the difference between the two measures:

The Employment Cost Index, or ECI, measures changes in employers’ cost of compensating workers, controlling for changes in the industrial-occupational composition of jobs. … The ECI is intended to indicate how the average compensation paid by employers would have changed over time if the industrial-occupational composition of employment had not changed… [It] controls for employment shifts across 2-digit industries and major occupations. The Employer Costs for Employee Compensation, or ECEC… is designed to measure the average cost of employee compensation. Accordingly, the ECEC is calculated by multiplying each job quote by its sample weight.

In other words, the ECI measures the change in average hourly compensation, controlling for shifts in the mix of industries and occupations. The ECEC simply measures the overall change in hourly compensation, including the effects of both changes in compensation for particular jobs, and changes in the mix of jobs.

Here are the two series for the full period both are available (1987-2014), both raw and adjusted for inflation ("real").

What do we learn from this?

First, the two series are closely correlated. This tells us that most of the variation in compensation is driven by changes within occupations and sectors, not by shifts in employment between occupations and sectors. This is clearly true at annual frequencies but it seems to be true over longer periods as well. For instance, let's compare the behavior of compensation in the five years since the end of the recession to the last period of strong wage growth, 1997-2004. The difference between the two periods in the average annual increase in nominal wages is almost exactly the same according to the two indexes — 2.7 points by the ECI, 2.6 points by the ECEC. In other words, slower wage growth in the recent period is entirely due to slower wages growth within particular kinds of jobs. Shifts in the composition of jobs have played no role at all.

On the face of it, the fact that almost all variation in aggregate compensation is driven by changes within employment categories, seems to favor a labor/political story of slower wage growth as opposed to a China or robots story. The most obvious versions of the latter two stories involve a disproportionate loss of high-wage jobs, whereas stories about weaker bargaining position of labor predict slower compensation growth within job categories. I wouldn't ask this one piece of evidence to carry a lot of weight in that debate. (I think it's stronger evidence against a skills-based explanation of slower wage growth.)

While the two series in general move together, the ECEC is more strongly cyclical. In other words, during periods of high unemployment and falling wages in general, there is also a shift in the composition of employment towards lower-paid occupations. And during booms, when unemployment is low and wages are rising in general, there is a shift in the direction of higher-paid job categories. [1] Insofar as wages and labor productivity are correlated, this cyclical shift between higher-wage and lower-wage sectors could help explain why employment is more stable than output. I've had the idea for a while that the Okun's law relationship -- the less than one-for-one correlation between employment and output growth -- reflects not only hiring/firing costs and overhead labor, but also shifts in the composition of employment in response to demand. In other words, in addition to employment adjustment costs at the level of individual enterprises, the Okun coefficient reflects cyclically varying degrees of "disguised unemployment" in Joan Robinson's sense. [2] This is an argument I'd like to develop properly someday, since it seems fairly obvious, potentially important and empirically tractable, and I haven't seen anyone else make it. [3] (I'm sure someone has.)

What's going on in the most recent year? Evidently, there has been no acceleration of wage growth for a given job, but the mix of jobs created has shifted toward higher-wage categories. This suggests that to the extent wages are rising faster, it's not a sign of labor-market pressures. (Some guy from Deutsche Bank interprets the same divergence as support for raising rates, which it's hard not to feel is deliberately dishonest.) As for which particular higher-wage job categories are growing more rapidly -- I don't know. And, what's going on in 1995? That year has by far the biggest divergence between the two series. It could well be an artifact of some kind, but if not, seems important. A large fall in the ECEC relative to the ECI could be a signature of deindustrialization. I'm not exploring the question further now (those exams…) but it would be interesting to ask analogous question with some series that extends earlier. It's likely that if we were looking at the 1970s-1980s, we would find a much larger share of variation in wage growth explained by compositional shifts.

Should we adjust for inflation? I give the "real" series here, but I am in general skeptical that there is any sense in which an ex post adjustment of money flows for inflation is more real than, say, The Real World on MTV. I am even more doubtful than usual in this case, because we are normally told to think that changes in nominal wages are the main determinant of inflation. Obviously in that case we have to think of the underlying labor-market process as determining a change in nominal wage. Still, if we do compute a "real" index, things look a little different. Real ECI rises 14 percent over the full 1987-2014 period, while real ECEC rises only 5 percent. So now we can say that about two-thirds of the increase in real wages within particular job categories over the past three decades, was offset by a shift in the composition of employment toward lower-paid job categories. (This is all in the first decade, 1987-1996, however.) This way of looking at things makes sense if we think the underlying wage-setting process, whatever it is, operates in terms of a basket of consumption goods.

This invites another question: How true is it that nominal wages move with inflation?

Conventional economics wisdom suggests we can separate wages into nominal and "real" components. This is on two not quite consistent grounds. First, we might suppose that workers and employers are implicitly negotiating contracts in terms of a fixe quantity of labor time for, on the one hand, a basket of wage goods, and on the other, a basket of produced goods (which will be traded for consumption good for the employer). This contract only incidentally happens to be stated in terms of money. The ultimate terms on which consumption goods for the workers exchange with consumption goods for the employer should not be affected by the units the trade happens to be denominated in. (In this respect the labor contract is just like any other contract.) This is the idea behind Milton Friedman's "natural rate of unemployment" hypothesis. In Friedman's story, causality runs strictly from inflation to unemployment. High inflation is not immediately recognized by workers, leading them to overestimate the basket of goods their wages will buy. So they work more hours than they would have chosen if they had correctly understood the situation. From this point of view, there's no cost to low unemployment in itself; the problem is just that unemployment will only be low if high inflation has tricked workers into supply too much labor. Needless to say, this is not the way anyone in the policy world thinks about the inflation-unemployment nexus today, even if they continue to use Friedman's natural rate language.

The alternative view is that workers and employers negotiate a money-wage, and then output prices are set as a markup over that wage. In this story, causality runs from unemployment to inflation. While Friedman thought an appropriate money-supply growth rate was the necessary and sufficient condition for stable prices, with any affect on unemployment just  collateral damage from changes in inflation, in this story keeping unemployment at an appropriate level is a requirement for stabilizing prices. This is the policy orthodoxy today.  (So while people often say that NAIRU is just another name for the natural rate of unemployment, in fact they are different concepts.) I think there are serious conceptual difficulties with the orthodox view, but we'll save those for another time. Suffice it to say that causality is supposed to run from low unemployment, to faster nominal wage growth, to higher inflation. So the question is: Is it really the case that faster nominal wage growth is associated with higher inflation?

Wage Growth and Inflation, 1947-2014

A simple scatterplot suggests a fairly tight relationship, especially at higher levels of wage growth and inflation. But if we split the postwar period at 1985, things look very different. In the first period, there's a close relationship — regressing inflation on nominal wage growth gives an R-squared of 0.81. (Although even then the coefficient is significantly less than 1.)

Wage Growth and Inflation, 1947-1985

Since 1985, though, the relationship is much looser, with an R-squared of 0.12. And even is that driven almost entirely by period of falling wages and prices in 2009; remove that and the correlation is essentially zero.

Wage Growth and Inflation, 1986-2014

So while it was formerly true that changes in inflation were passed one for one into changes in nominal wages, and/or changes in nominal wage growth led to similar changes in inflation, neither of those things has been true for quite a while now. In recent decades, faster nominal wage growth does not translate into higher inflation.

Obviously, a few scatterplots aren't dispositive, but they are suggestive. So supposing that there has been a  delinking of wage growth and inflation, what conclusions might we draw? I can think of a couple.

On the one hand, maybe we shouldn't be so dismissive of  the naive view that inflation reduces the standard of living directly, by raising the costs of consumption goods while incomes are unchanged. There seems to be an emerging conventional wisdom in this vicinity. Here for instance is Gillian Tett in the FT, endorsing the BIS view that there's nothing wrong with falling prices as long as asset prices stay high. (Priorities.) In the view of both Keynes (in the GT; he modified it later) and Schumpeter, inflation was associated with higher nominal but lower real wages, deflation with lower nominal but higher real wages. I think this may have been true in the 19th century. It's not impossible it could be true in the future.

On the other hand. If the mission of central banks is price stability, and if there is no reliable association between changes in wage growth and changes in inflation, then it is hard to see the argument for tightening in response to falling unemployment. You really should wait for direct evidence of rising inflation. Yet central banks are as focused on unemployment as ever.

It's perhaps significant in this regard that the authorities in Europe are shifting away from the NAIRU (Non-Accelerating Inflation Rate of Unemployment) and increasingly talking about the NAWRU (Non-Accelerating Wage Rate of Unemployment). If the goal all along has been lower wage growth, then this is what you should expect: When the link between wages and inflation weakens, the response is not to find other tools for controlling inflation, but other arguments for controlling wages. This may be the real content of the "competitiveness" discourse. Elevating competitiveness over price stability as overarching goal of policy lets you keep pushing down wages even when inflation is already low.

Worth noting here: While the ECB's "surrender Dorothy" letter to the Spanish government ordered them to get rid of price indexing, their justification was not, as you might expect, that indexation contributes to inflationary spirals. Rather it was that it is "a structural obstacle to the adjustment of labour costs" and "contribute to hampering competitiveness." [4]  This is interesting. In the old days we would have said, wage indexing is bad because it won't affect real wages, it just leads to higher inflation. But apparently in the new dispensation, we say that wage indexing is bad precisely because it does affect real wages.




[1]  This might seem to contradict the previous point but it doesn't, it's just that the post-2009 recovery period includes both a negative composition shift in 2008-2009, when unemployment was high, and a positive compositional shift in 2014, which cancel each other out.

[2] From A Theory of Employment: "Except under peculiar conditions, a decline in effective demand which reduces the amount of employment offered in the general run of industries will not lead to 'unemployment' in the sense of complete idleness, but will rather drive workers into a number of occupations [such as] selling match-boxes in the Strand, cutting brushwood in the jungles, digging potatoes on allotments which are still open to them. A decline in one sort of employment leads to an increase in another sort, and at first sight it may appear that, in such a case, a decline in effective demand does not cause unemployment at all. But the matter must be more closely examined. In all those occupations which the dismissed workers take up, their productivity is less than in the occupations that they have left."

[3] The only piece I know of that makes the connection between demand and productivity variation across sectors is this excellent article by John Eatwell (which unfortunately doesn't seem to be available online), but it is focused on long run variation, not cyclical.

[4] The ECB's English is not the most felicitous, is it? The Spanish version is "contribuyen a dificultar la competitividad y el crecimiento," which also doesn't strike me as a phrase that a native speaker would write. Maybe it sounds better in the original German.

Strange Defeat

Following up on the previous post, below the fold is an article Arjun and I wrote last year for the Indian publication Economic and Political Weekly, on how liberal New Keynesian economists planted the seeds of their own defeat in the policy arena. 

I should add that Krugman is very far from the worst in this respect. If I criticize my soon-to-be colleague so much, it's only because of his visibility, and because the clarity of his writing and his genuinely admirable political commitments make it easier to see the constraints imposed by his theoretical commitments. You might say that his distinct virtues bring the common vices into sharper focus.

The Nonexistent Rise in Household Consumption

Did you know that about 10 percent of private consumption in the US consists of Medicare and Medicaid? Despite the fact that these are payments by the government to health care providers, they are counted by the BEA both as income and consumption spending for households.

I bet you didn't know that. I bet plenty of people who work with the national income accounts for a living don't know that. I know I didn't know it, until I read this new working paper by Barry Cynamon and Steve Fazzari.

I've often thought that the best macroeconomics is just accounting plus history. This paper is an accounting tour de force. What they've done is go through the national accounts and separate out the components of household income and expenditure that represent cashflows received and made by households, from everything else.

Most people don't realize how much of what goes into the headline measures of household income and household consumption does not actually correspond to any flow of money to or from households. In 2011 (the last year covered by the paper), personal consumption expenditure was given as just over $10 trillion. But of that, only about $7.5 trillion was money spent by households on goods and services. Of the rest, as of 2011:

- $1.2 trillion was imputed rents on owner-occupied housing. The national income and product accounts treat housing on the principle that the real output of housing should be the same whether or not the person living in the house happens to be the same person who owns it. So for owner-occupied housing, they impute an "owner equivalent rent" that the resident is implicitly paying to themselves for use of the house.  This sounds reasonable, but it conflicts with another principle of the national accounts, which is that only market transactions are recorded. It also creates measurement problems since most owned residences are single-family homes, for which there isn't a big rental market, so the BEA has to resort to various procedures to estimate what the rent should be. One result of the procedures they use is that a rise in hoe prices, as in the 2000s, shows up as a rise in consumption spending on imputed rents even if no additional dollars change hands.

- $970 billion was Medicare and Medicaid payments; another $600 billion was employer purchases of group health insurance. The official measures of household consumption are constructed as if all spending on health benefits took the form of cash payments, which they then chose to spend on health care. This isn't entirely crazy as applied to employer health benefits, since presumably workers do have some say in how much of their compensation takes the form of cash vs. health benefits; tho one wouldn't want to push that assumption that too far. But it's harder to justify for public health benefits. And, justifiable or not, it means the common habit of referring to personal consumption expenditure as "private" consumption needs a large asterix.

- $250 billion was imputed bank services. The BEA assumes that people accept below-market interest on bank deposits only as a way of purchasing some equivalent service in return. So the difference between interest from bank deposits and what it would be given some benchmark rate is counted as consumption of banking services.

- $400 billion in consumption by nonprofits. Nonprofits are grouped with the household sector in the national accounts. This is not necessarily unreasonable, but it creates confusion when people assume the household sector refers only to what we normally think of households, or when people try to match up the aggregate data with surveys or other individual-level data.

Take these items, plus a bunch of smaller ones, and you have over one-quarter of reported household consumption that does not correspond to what we normally think of as consumption: market purchases of goods and services to be used by the buyer.

The adjustments are even more interesting when you look at trends over time. Medicare and Medicaid don't just represent close to 10 percent of reported "private" consumption; they represent over three quarters of the increase in consumption over the past 50 years. More broadly, if we limit "consumption" to purchases by households, the long term rise in household consumption -- taken for granted by nearly everyone, heterodox or mainstream -- disappears.

By the official measure, personal consumption has risen from around 60 percent of GDP in the 1950s, 60s and 70s, to close to 70 percent today. While there are great differences in stories about why this increase has taken place, almost everyone takes for granted that it has. But if you look at Cynamon and Fazzari's measure, which reflects only market purchases by households themselves, there is no such trend. Consumption declines steadily from 55 percent of GDP in 1950 to around 47 percent today. In the earlier part of this period, impute rents for owner occupied housing are by far the biggest part of the difference; but in more recent years third-party medical expenditures have become more important. Just removing public health care spending from household consumption, as shown in the pal red line in the figure, is enough to change a 9 point rise in the consumption share of GDP into a 2 point rise. In other words, around 80 percent of the long-term rise in household consumption actually consists of public spending on health care.

In our "Fisher dynamics" paper, Arjun Jayadev and I showed that the rise in debt-income ratios for the household sector is not due to any increase in household borrowing, but can be entirely explained by higher interest rates relative to income growth and inflation. For that paper, we wanted to adjust reported income in the way that Fazzari and Cynamon do here, but we didn't make a serious effort at it. Now with their data, we can see that not only does the rise in household debt have nothing to do with any household decisions, neither does the rise in consumption. What's actually happened over recent decades is that household consumption as a share of income has remained roughly constant. Meanwhile, on the one hand disinflation and high interest rates have increased debt-income ratios, and on the other hand increased public health care spending and, in the 2000s high home prices, have increased reported household consumption. But these two trends have nothing to do with each other, or with any choices made by households.

There's a common trope in left and heterodox circles that macroeconomic developments in recent decades have been shaped by "financialization." In particular, it's often argued that the development of new financial markets and instruments for consumer credit has allowed households to choose higher levels of consumption relative to income than they otherwise would. This is not true. Rising debt over the past 30 years is entirely a matter of disinflation and higher interest rates; there has been no long run increase in borrowing. Meanwhile, rising consumption really consists of increased non-market activity -- direct provision of housing services through owner-occupied housing, and public provision of health services. This is if anything a kind of anti-financialization.

The Fazzari and Cynamon paper has radical implications, despite its moderate tone. It's the best kind of macroeconomics. No models. No econometrics. Just read the damn tables, and think about what the numbers mean.

A Harrodian Perspective on Secular Stagnation

I’ve mentioned before, I think a useful frame to think about the secular stagnation debate through is what’s become known as Harrod’s growth model. [1] My presentation here is a bit different from his.

Start with the familiar equation:

S - I + T - G = X - M

Private savings minus private investment, plus taxes minus government spending, equal exports minus imports. [2] If the variables refer to the actual, realized values, then this is an accounting identity, always true by definition. Anything that is produced must be purchased by someone, for purposes of consumption, investment, export or provision of public services. (Unsold goods in a warehouse are a form of investment.) If the variables refer to expected or intended values, which is how Harrod used them, then it is not an identity but an equilibrium condition. It describes the condition under which businesses will be “satisfied that they have produced neither more nor less than the right amount.”

The next step is to rearrange the equation as S - (G - T) - (X - M) = I. We will combine the government and external balances into A = (G - T) + (X - M). Now divide through by Y, writing  s = S/Y and a = A/Y. This gives us:

s - a = I/Y

Private savings net of government and foreign borrowing, must equal private investment. Next, we decompose investment. Logically, investment must either provide the new capital goods required for a higher level of output, or replace worn-out or obsolete capital goods, or be a shift toward a more capital-intensive production technique. [3] So we write:

s - a = gk + dk + delta-k

where g is the growth rate of the economy, k is the current capital-output ratio, d is the depreciation rate (incorporating obsolescence as well as physical wearing-out) and delta-k is the change in the capital-output ratio.

What happens if this doesn’t hold? Realized net savings and investment are always equal. So if desired savings and desired investment are different, that means that somebody’s expectations were not fulfilled. For a situation to arise in which desired net savings are greater than desired investment, either people must have saved less than they wish they had in retrospect, or businesses must have investment more than they wish they had in retrospect. Either way, expenditure in the next period will fall.

What prevents output from falling to zero, in this case? Remember, some consumption is linked to current income, but some is not. This means that when income falls, consumption falls less than proportionately. Which is equivalent to saying that when income falls, there is also a fall in the fraction of income that is saved. In other words, if the marginal propensity to save out of income is less than one, then s — which, remember, is average saving rate — must be a positive function of the current level of output. So the fall in output resulting from a situation in which s > I/Y will eventually cause s to fall sufficiently to bring desired saving into equality with desired investment. The more sensitive is consumption to current income, the larger the fall in income required; if investment is also sensitive to current income, then a still larger fall in income will be required. (If investment is more sensitive than saving to current income, this adjustment process will not work and the decline in output will continue until investment reaches zero.) This is simply the logic of the Keynesian multiplier.

In addition to current income, saving is also a function of the profit rate. Saving is higher out of profits than out of wages, partly because profit recipients are typically richer than wage-earners, but also because are large fraction of profits remain within the business sector and are not available for consumption. [4] Finally, saving is usually assumed to be a function of the interest rate. The desired capital output ratio may also be a function of the interest rate. All the variables are of course also subject to longer term social, technological and economic influences.

So we write

s(u, i, p) - a = gk + dk + delta-k(i, p)

where u is the utilization rate (i.e. current output relative to some measure of trend or potential), i is some appropriate interest rate, and p is the profit share. s is a positive function of utilization, interest rates and the profit share, and delta-k is a negative function of the interest rate and a positive function of the profit rate. Since the profit share and interest rate are normally positive functions of the current level of output, their effects on savings are stabilizing — they reduce the degree to which output must adjust to maintain equality of desired net savings equal and investment. The effect of interest rates on investment is also stabilizing, while the effect of the profit share on investment (as well as any direct effect of utilization on investment, which we are not considering here) are destabilizing.

How does this help make sense of secular stagnation?

In modern consensus macroeconomics, it is implicitly assumed that savings and/or investment are sufficiently sensitive to interest rates that equilibrium can be normally be maintained entirely by changes in interest rates, with only short-term adjustments of output while interest rates move to the correct level. The secular stagnation idea — in both its current and original 1940s edition, as well as the precursor ideas about underconsumption going back to at least J. A. Hobson — is that at some point interest rate adjustment may no longer be able to play this role. In that case, desired investment will not equal desired saving at full employment, so there will be a persistent output gap.

There are a number of reasons that s - a might rise over time. As countries grow richer, the propensity to consume may fall simply because people’s people’s desires for goods and services are finite. This was what Keynes and Alvin Hansen (who coined the term "secular stagnation") believed. Desired saving may also rise as a result of an upward redistribution of income, or a shift from wage income to profit income, or an increase in the share of profits retained by firms. [5] Unlike the progressive satiation of consumption demand, these three factors could in principle just as easily evolve in the other direction. Finally, government deficits or net exports might decline — but again, they might also increase.

On the right side of the equation, growth may fall for exogenous reasons, slowing population growth being the most obvious. This factor has been emphasized in recent discussions. Depreciation is hardly mentioned in today’s secular stagnation debate, but it is prominent in the parallel discussion of underconsumption in the Marxist tradition. The important point here is to remember that depreciation refers not only to the physical wearing-out or using-up of capital goods, but also to capital goods displaced by competition or obsolescence. In competitive capitalism, businesses invest not only to increase aggregate capacity, but to win market share from each other. Much of depreciation represents capital that goes out of use not because it has ceased to be physically productive, but because it is attached to businesses that have lost out in the competitive struggle. Under conditions of monopoly, the struggle over market share is suppressed, so effective depreciation rates, and hence desired investment, will be lower. Physical depreciation does also exist, and will change as the production technology changes. If there is a secular tendency toward longer-lived means of production, that will pull down desired investment. As for delta-k, it is clearly the case that the process of industrialization involves a large upward shift in the capital-output ratio. But it’s hard to imagine it continuing to rise indefinitely; there are reasons (like the shift toward services) to think it might reach a peak and then decline.

So for secular, long-term trends tending to raise desired saving relative to desired investment we have: (1) the progressive satiation of consumption demand; (2) slowing population growth; (3) increasing monopoly power; and (4) the end of the industrialization process. Factors that might either raise or lower desired savings relative to investment are: (5) changes in the profit share; (6) changes in the fraction of profits retained in the business sector; (7) changes in the distribution of income; (8) changes in net exports; (9) changes in government deficits; and (10) changes in the physical longevity of capital goods. Finally, there are factors that will tend to raise desired investment relative to desired saving. The include: (11) consumption as status competition (this may offset or even reverse the effect of greater inequality on consumption); (12) social protections (public pensions, etc.) that reduce the need for precautionary and lifecycle saving; (13) easier access to credit, for consumption and/or investment; and (14) major technological changes that render existing capital goods obsolete, increasing the effective depreciation rate. These final four factors will offset any tendency toward secular stagnation.

It’s a long list, but I think it’s close comprehensive. Different versions of the stagnation story emphasize various of these factors, and their relative importance has varied in different times and places. I don’t think there is any a priori basis for saying that any of them are more or less important in general.

One problem with this conversation, from my point of view, is that people have a tendency to pick out a couple items from this list as the story, without considering the whole question systematically. For instance, there’s a very popular story in left Keynesian circles that makes it all about (7), offset for a while by (13) and perhaps (11). I don’t doubt that greater income inequality has increased desired private saving. It may be that this is the main factor at work here. But people should not be confidently asserting it is before clearly posing the question and analyzing the full range of possible answers.

In a future post we will think about how to assess the relative importance of these factors empirically.

[1] While the model itself is simple, the interpretation of it — the question it’s intended to answer — is quite controversial. Harrod himself intended it as a model of economic dynamics — that is, describing the system’s transition from one state to another in historical time. As it entered mainstream economics (via the criticism of Samuelson) and also much of structuralist work, it instead became treated as a model of economic growth — that is, of a long-run equilibrium one of whose variables happens to be the growth rate rather than the level of growth. It seems to me that while Harrod clearly was interested in dynamics, not growth in the current sense, the classic article is in fact ambivalent. In particular, Harrod is simply inconsistent in his definition of g: sometimes it is the change in output from one period to the next, while at other times it is the normal or usual change in output expected by business. Furthermore, as Joan Robinson pointed out, his famous knife-edge results depend on using the average savings rate as a parameter, which only makes sense if we are describing a long-run equilibrium. In the short period, it’s the marginal savings rate that is stable, while the average savings rate varies with output. So while it is true that Harrod thought he was writing about economic dynamics, the model he actually wrote is inconsistent. One way to resolve this inconsistency is to treat it as a model of equilibrium long-run growth, as Samuelson did; the other way, which I take here, is to treat it as a Keynesian short-run model in which the current, usual or expected growth rate appears as a parameter.  

[2] Strictly speaking it should be the current account balance rather than the trade balance but there's no harm in ignoring cross-border income flows here.

[3] I am writing here in terms of a quantifiable capital stock, which I have deep misgivings about. But it makes the exposition much simpler. 

[4] This is true even in the "disgorge the cash" era, because much of the higher payouts from corporations go to financial institutions rather to households, and thus stay in the business sector.

[5] On the other hand, in a world where investment is constrained by funding, a higher share of profits retained will raise investment as well as savings, leaving its overall effect ambiguous.



EDIT: I think I've been misled by reading too much of the Keynesian classics from the 1930s and 40s. The dynamic I describe in this post is correct for that period, but not quite right for the US economy today. Since 1980, the average private savings rate has moved countercyclically, rather than procyclically as it did formerly and as I suggest here. So the mechanism that prevents booms and downturns from continuing indefinitely is no longer -- as Keynes said, and I unthinkingly repeated -- the behavior of private savings, but rather of the government and external balances. I can't remember seeing anything written about this fundamental change in business cycle dynamics, which is a bit surprising, but it's unambiguous in the data.

Fortunately we are interested here in longer term changes rather than cyclical dynamics, so the main argument of this post and the sequel shouldn't be too badly undermined.


EDIT 2: Of course this change has been written about, what was I thinking. For example, Andrew Glyn, Capitalism Unleashed:

From Marx to Keynes at least, consumption was viewed as an essentially passive component of the growth process. Capital accumulation, investment spending on machinery and buildings, was the essential driving force on the demand as well as on the supply side. It was the capitalists’ access to finance which allowed capital spending to exceed the previous period’s savings and fuelled the expansion of demand; future profits ensured that such borrowing was repaid with a real return. Deficit spending by the government could, in wartime for example, impart a similar impulse to demand, at least till capital markets took fright at the growing debt interest burden and worries about inflation. However household consumption, some two-thirds of aggregate demand, was seen as playing the role of sustaining the current output level rather than driving it up. Savings ratios often fell during recessions, as consumers attempted to maintain spending in the face of falling incomes. Indeed, Milton Friedman criticized the Keynesians for exaggerating the dependence of consumption on current income and ignoring the extent to which savings could be used to ‘smooth’ out the path of consumption. More recently, rather than acting as a stabilizing influence, sharp falls in the savings ratio have occurred during expansions. By boosting consumption proportionately more than the rise in incomes this has intensified upswings, with the danger of sharp falls in demand if savings rebound sharply when the expansion slackens and pessimism builds up.

The Cash and I

Martin Wolf in the FT the other day:

The third challenge is over the longer-term sources of demand. I look at this issue in terms of the sectoral financial balances – the balances between income and spending – in the household, business, external and government sectors. The question, then, is where expansion will come from. In the first quarter of this year the principal offset to fiscal contraction was the declining household surplus. 

What is needed, as well, is a big swing towards surplus in the US current account or a jump in corporate investment, relative to retained profits. Neither seems imminent, though the second seems more likely than the first. The worry is that the only way to balance the economy will be via big new bubbles. If so, this is not the fault of the Fed. It is the fault of structural features of the domestic and global economies...

This is a good point, which should be made more. If we compare aggregate expenditure today to expenditure just before the recession, it is clear that the lower level of demand today is all about lower  consumption. But maybe that's not the best comparison, because during the housing boom period, consumption was historically high. If we take a somewhat longer view, what's unusually low today is not household consumption, but business investment. Weak demand is about I, not C.

This is especially clear when we compare investment by businesses to what they are receiving in the form of profits, or, better cashflow from operations -- after-tax profits plus depreciation. [1] Here is the relationship over the past 40 years:

Corporate Investment and Cashflow from Operations as Fraction of Total Assets, 1970-2012

The graph shows annualized corporate investment and cashflow, normalized by total assets. Each dot is data from one quarter; to keep the thing legible, I've only labeled the fourth quarter of each year. As you can see, there used to be a  clear relationship between corporate profitability and corporate investment. For every additional $150, more or less, that a corporation took in from operations, it would increase capital expenditures by $100. This relationship held consistently through the 1960s (not shown), the 1970s, the 1980s and 1990s.

But now look at the past ten years, the period after 2001Q4.  Corporate investment rates are substantially lower throughout this period than at any earlier time (averaging around 3.5% of total assets, compared with 5% of assets for 1960-2001). And the relationship between aggregate profit and investment rates has simply disappeared.

Some people might say that the problem is in the financial system, that even profitable businesses can't borrow because of a breakdown in intermediation, a shortage of liquidity, an unwillingness of risk-averse investors to hold their debt, etc. I don't buy this story for a number of reasons, some of which I've laid out in recent posts here. But it at least has some certain prima facie plausibility for the period following the great financial crisis. Not for for the whole decade-plus since 2001. Saying that investment is low today because businesses can't find anyone to buy their bonds is merely wrong. Saying that's why investment was low in 2005 is absurd.

(And remember, these are aggregates, so they mainly reflect the largest corporations, the ones that should have the least problems borrowing.)

So what's a better story?

I am going to save my full answer for another post. But regular readers will not be surprised that I think the key is a shift in the relationship between corporations and shareholders. I think there's a sense in which the binding constraint on investment has changed from the terms on which management can get funds into the corporation, from profits or borrowing, to the terms are on which they can keep them from going out, to investors. But the specific story doesn't matter so much here. You can certainly imagine other explanations. Like, "the China price" -- even additional capacity that would be profitable today won't be added if it there's a danger of lower-cost imports entering that market.

The point of this post is just that corporate investment is historically low, both in absolute terms and relative to profitability. And because this has been true for a decade, it is hard to attribute this weakness to credit constraints, or believe that it will be responsive to monetary policy. (This is even more true when you recall that the link between corporate borrowing and investment has also essentially disappeared.) By contrast, household consumption remains high. I have the highest respect for Steve Fazzari, and agree that high income inequality is a key metric of the fucked-upness of our economy. But I don't think it makes sense to think of the current situation in terms of a story where high inequality reduces demand by holding down consumption.

Consumption is red, on the right scale; investment is blue, on the left. Both as shares of GDP.

As I say, I'll come back in a future post to my on preferred explanation for why a comparably profitable firm, facing comparable credit conditions, will invest less today than 20 or 30 years ago.

In the meantime, one other thing. That first graph is a nice tool for showing how a Marxist thinks about business cycles.

If you look at the graph carefully, you'll see the points follow counterclockwise loops. It's natural to see this as cycles. Like this:

Start from the bottom of a cycle, at a point like 1992. A rise in profits from whatever source leads to higher investment, mainly as a source of funds and but also because it raises expectations of future profitability. That's the lower right segment of the cycle. High investment eventually runs into supply constraints, typically in the form of a rising wage share.[1] At that point profits begin to fall. Investment, however, continues high for a while, as the credit system allows firms to bridge a growing financing gap. That's the upper right segment of the cycle. Eventually, though, if profits don't recover, investment will follow them downward. This turning point often involves a financial crisis and/or abrupt fall in asset values, like the collapse of tech stocks in 2000. This is the upper left segment of the cycle.  Finally, in the  lower left, both profits and investment are low. But after some time the conditions for profitability are restored, and we move toward the right and begin a new cycle. This last step is less reliable than the others. It's quite possible for the economy to come to rest at the lower left and wobble there for a while without any sustained change in either profits or investment. We see this in 2002-2003 and in 1988-1991.

(I think the investment boom of the late 70s and the persistent slump of the early 1990s are two of the more neglected episodes in recent economic history. The period around 1990, in particular, seems to have all the features that are supposed to be distinctive to the current macroeconomic conjuncture. At the time, people even called it a balance-sheet recession!)

For now, though, we're not interested in the general properties of cycles. We're interested in how flat and low the most recent two are, compared with earlier ones. That is the structural feature that Martin Wolf is pointing to. And it's not a new feature of the post financial crisis period, it's been the case for a dozen years at least, only temporarily obscured by the housing bubble.



UPDATE: In comments, Seth Ackerman asks if maybe using total assets to normalize investment and profits is distorting the picture. It's a good question, but the answer is no. Here's the same thing, with trend GDP in the denominator instead:

As you can see, the picture is basically the same. Investment in the 200s is still visibly depressed compared with earlier decades, and the relationship between profits and investment is much weaker. Of course, it's always possible that current high profits will lead an investment boom in the next few years...



[1] Cash from operations is better than profits for at least two reasons. First, from the point of view of aggregate demand, we are interested in gross not net investment. A dollar of investment stimulates demand just as much whether it's replacing old equipment or adding new. So our measure of income should also be gross of depreciation. Second, there are major practical and conceptual issues with measuring depreciation. Changes in accounting standards may result in very different official depreciation numbers in economically identical situations. By combining depreciation and profits, we avoid the problem of the fuzzy and shifting line between them, making it more likely that we are comparing equivalent quantities.

[2] A rising wage share need not, and often does not, take the form of rising real wages. In recent cycles especially, it's more likely to combine flat real wages with a rising relative cost of wage goods.

New Keynesians Don't Believe Their Models

Here's the thing about about saltwater, New Keynesian economists: They don't believe their own theory.

Via John Cochrane, here is a great example. In the NBER Macroeconomics Annual a couple years ago, Gauti Eggertson laid out the canonical New Keynesian case for the effectiveness of fiscal policy when interest rates are at the Zero Lower Bound. In the model Eggertson describes there -- the model that is supposed to provide the intellectual underpinnings for fiscal stimulus -- the multiplier on government spending at the ZLB is indeed much larger than in normal conditions, 2.3 rather than 0.48. But the same model says that at the ZLB, cuts in taxes on labor are contractionary, with a multiplier of -1. Every dollar of "stimulus" from the Making Work Pay tax credit, in other words, actually reduced GDP by a dollar. Or as Eggertson puts it, "Cutting taxes on labor ... is contractionary under the circumstances the United States is experiencing today. "

Now, obviously there are reasons why one might believe this. For instance, maybe lower payroll taxes just allow employers to reduce wages by the same amount, and then in response to their lower costs they reduce prices, which is deflationary. There's nothing wrong with that story in principle. No, the point isn't that the New Keynesian claim that payroll tax cuts reduce demand is wrong -- though I think that it is. The point is that nobody actually believes it.

In the debates over the stimulus bill back at the beginning of 2009, everyone agreed that payroll tax cuts were stimulus just as much as spending increases. The CBO certainly did. There were plenty of "New Keynesian" economists involved in that debate, and while they may have said that tax cuts would boost demand less than direct government spending, I'm pretty sure that not one of them said that payroll tax cuts would actually reduce demand. And when the payroll tax cuts were allowed to expire at the end of 2012, did anyone make the case that this was actually expansionary? Of course not. The conventional wisdom was that the payroll tax cuts had a large, positive effect on demand, with a multiplier around positive 1. Regardless of good New Keynesian theory.

As a matter of fact, even Eggertson doesn't seem to believe that raising taxes on labor will boost demand, whether or not it's what the math says. The "natural result" of his model, he admits, is that any increase in government spending should be financed by higher taxes. But:

There may, however, be important reasons outside the model that suggest that an increase in labor and capital taxes may be unwise and/or impractical. For these reasons I am not ready to suggest, based on this analysis alone, that raising capital and labor taxes is a good idea at zero interest rates. Indeed, my conjecture is that a reasonable case can be made for a temporary budget deficit to finance a stimulus plan... 

Well, yeah. I think most of us can agree that raising payroll taxes in a recession is probably not the best idea. But at this point, what are we even doing here? If you're going to defer to arguments "outside the model" whenever the model says something inconvenient or surprising, why are you even doing it?


EDIT: I put this post up a few days ago, then took it down because it seemed a little thin and I thought I would add another example or two of the same kind of thing. But I'm feeling now that more criticism of mainstream economics is not a good use of my time. If that's what you want, you should check out this great post by Noah Smith. Noah is so effective here for the same reason that he's sometimes so irritatingly wrong -- he's writing from inside the mainstream. The truth is, to properly criticize these models, you have to have a deep knowledge of them, which he has and I do not.

Arjun and I have a piece in an upcoming Economics and Politics Weekly on how liberal, "saltwater" economists share the blame for creating an intellectual environment favorable to austerian arguments, however much they oppose them in particular cases. I feel pretty good about it -- will link here when it comes out -- I think for me, that's enough criticism of modern macro. In general, the problem with radical economists is they spend too much time on negative criticism of the economics profession, and not enough making a positive case for an alternative. This criticism applies to me too. My comparative advantage in econblogging is presenting interesting Keynesian and Marxist work.

One thing one learns working at a place like Working Families, the hard thing is not convincing people that shit is fucked up and bullshit, the hard thing is convincing them there's anything they can do about it.  Same deal here: The real challenge isn't showing the other guys are wrong, it's showing that we have something better.

Reviving the Knife-Edge: Aggregate Demand in the Long Run

The second issue of the new Review of Keynesian Economics is out, this one focused on growth. [1] There's a bunch of interesting contributions, but I especially like the piece by Steve Fazzari, Pietro Ferri, Edward Greenberg and Anna Maria Variato, on growth and aggregate demand.

The starting point is the familiar puzzle that we have a clear short-run story in which changes in output  [2] on the scale of the business cycle are determined by aggregate demand -- that is, by changes in desired expenditure relative to income. But we don't have a story about what role, if any, aggregate demand plays in the longer run.

The dominant answer -- unquestioned in the mainstream [3], but also widespread among heterodox writers -- is, it doesn't. Economic growth is supposed to depend on a different set of factors -- technological change, population growth and capital accumulation -- than those that influence demand in the short run. But it's not obvious how you get from the short-run to the long -- what mechanism, if any, that ensures that the various demand-driven fluctuations will converge to the long-run path dictated by these "fundamentals"?

This is the question posed by Fazzari et al., building on Roy Harrod's famous 1939 article. As Harrod noted, there are two relations between investment and output: investment influences output as a source of demand in the short run, and in the longer run higher output induces investment in order to maintain a stable capital-output ratio. More investment boosts growth, for the first channel, the multiplier; growth induces investment, through the second, the accelerator. With appropriate assumptions you can figure out what combinations of growth and investment satisfy both conditions. Harrod called the corresponding growth paths the "warranted" rate of growth. The problem is, as Harrod discovered, these combinations are dynamically unstable -- if growth strays just a bit above the warranted level, it will accelerate without limit; if falls a little below the warranted rate, it will keep falling til output is zero. 

This is Harrod's famous "knife-edge." It's been almost entirely displaced from the mainstream by Solow type growth models. Solow argued that the dynamic instability of Harrod's model was due to the assumption of a fixed target capital-output ratio, and that the instability goes away if capital and labor are smoothly substitutible. In fact, Harrod makes no such assumption -- his 1939 article explicitly considers the possibility that capitalists might target different capital-output ratios based on factors like interest rates. More generally, Solow didn't resolve the problem of how short-run demand dynamics converge to the long-run supply-determined growth path, he just assumed it away. 

The old textbook solution was price flexibility. Demand constraints are supposed to only exist because prices are slow to adjust, so given enough time for prices to reach market-clearing levels, aggregate demand should cease to exist. The obvious problem with this, as Keynes already observed, is that while flexible prices may help to restore equilibrium in individual markets, they operate in the wrong direction for output as a whole. A severe demand shortfall tends to produce deflation, which further reduces demand for goods and services; similarly, excessive demand leads to inflation, which tends -- though less certainly -- to further increase demand. As Leijonhufvud notes, it's a weird irony that sticky wages and/or prices are held to be the condition of effective demand failures, when the biggest demand failure of them all, the Depression, saw the sharpest falls in both wages and prices on record. 

The idea that if it just runs its course, deflation -- via the real balance effect or some such -- will eventually restore full employment is too much even for most economists to swallow. So the new consensus replaces price level adjustment with central bank following a policy rule. In textbooks, this is glossed as just hastening an adjustment that would have happened on its own via the price level, but that's obviously backward. When an economy actually does develop high inflation or deflation, central banks consider their jobs more urgent, not less so. It's worth pausing a moment to think about this. While the central bank policy rule is blandly presented as just another equation in a macroeconomic model, the implications are actually quite radical. Making monetary policy the sole mechanism by which the economy converges to full employment (or the NAIRU) implicitly concedes that on its own, the capitalist economy is fundamentally unstable. 

While the question of how, or whether, aggregate demand dynamics converge to a long-run growth path has been ignored or papered over by the mainstream, it gets plenty of attention from heterodox macro. Even in this one issue of ROKE, there are several articles that engage with it in one way or another. The usual answer, among those who do at least ask the question, is that the knife-edge result must be wrong, and indicates some flaw in the way Harrod posed the problem. After all, in real-world capitalist economies, output appears only moderately unstable. Many different adjustments have been proposed to his model to make demand converge to a stable path.

Fazzari et al.'s answer to the puzzle, which I personally find persuasive, is that demand dynamics really are that unstable -- that taken on their own the positive feedbacks between income, expenditure and investment would cause output to spiral toward infinity or fall to zero. The reasons this doesn't happen is because of the ceiling imposed by supply constraints and the the floor set by autonomous expenditure (government spending, long-term investment, exports, etc.). But in general, the level of output is set by expenditure, and there is no reason to expect desired expenditure to converge to exactly full utilization of the economy's resources. When rising demand hits supply constraints, it can't settle at full employment, since in general full employment is only reached on the (unfulfillable) expectation of more-than-full employment. 

Upward demand instability can drive demand to a level that fully employs labor resources. But the full employment path is not stable. ... The system bounces off the ceiling onto an unstable declining growth path.

I won't go through the math, which in any case isn't complicated -- is trivial, even, by the standards of "real" economics papers. The key assumptions are just a sufficiently strong link between income and consumption, and a target capital output ratio, which investment is set to maintain. These two assumptions together define the multiplier-accelerator model; because Fazzari et al explicitly incorporate short-term expectations, they need a third assumption, that unexpected changes in output growth cause expectations of future growth to adjust in the same direction -- in other words, if growth is higher than expected this period, people adjust their estimates of next period's growth upward. These three assumptions, regardless of specific parameter values, are enough to yield dynamic instability, where any deviation from the unique stable growth path tends to amplify over time.

The formal model here is not new. What's more unusual is Fazzari et al.'s suggestion that this really is how capitalist economies behave. The great majority of the time, output is governed only by aggregate demand, and demand is either accelerating or decelerating. Only the existence of expenditure not linked to market income prevents output from falling to zero in recessions; supply constraints -- the productive capacity of the economy -- matters only occasionally, at the peaks of businesses cycles.

Still, one might say that if business-cycle peaks are growing along a supply-determined path, then isn't the New Consensus right to say that the long run trajectory of the economy is governed only by the supply side, technology and all that? Well, maybe -- but even if so,this would still be a useful contribution in giving a more realistic account of how short-term fluctuations add up to long-run path. It's important here that the vision is not of fluctuations around the full-employment level of output, as in the mainstream, but at levels more or less below it, as in the older Keynesian vision. (DeLong at least has expressed doubts about whether the old Keynsians might not have been right on this point.) Moreover, there's no guarantee that actual output will spend a fixed proportion of time at potential, or reach it at all. It's perfectly possible for the inherent instability of the demand process to produce a downturn before supply constraints are ever reached. Financial instability can also lead to a recession before supply constraints are reached (altho more often, I think, the role of financial instability is to amplify a downturn that is triggered by something else.)

So: why do I like this paper so much?

First, most obviously, because I think it's right. I think the vision of cycles and crises as endogenous to the growth process, indeed constitutive of it, is a better, more productive way to think about the evolution of output than a stable equilibrium growth path occasionally disturbed by exogenous shocks. The idea of accelerating demand growth that sooner or later hits supply constraints in a more or less violent crisis, is just how the macroeconomy looks. Consider the most obvious example, unemployment:

What we don't see here, is a stable path with normally distributed disturbances around it. Rather, we see  unemployment falling steadily in expansions and then abruptly reversing to large rises in recessions. To monetarists, the fact that short-run output changes are distributed bimodally, with the economy almost always in a clear expansion or clear recession with nothing in between, is a sign that the business cycle must be the Fed's fault. To me, it's more natural to think that the nonexistence of "mini-recessions" is telling us something about the dynamics of the economic process itself -- that capitalist growth, like love, 

is a growing, or full constant light,
And his first minute, after noon, is night.

Second, I like the argument that output is demand-constrained at almost all times. There is no equilibrium between "aggregate supply" and "aggregate demand"; rather, under normal conditions the supply side doesn't play any role at all. Except for World War II, basically, supply constraints only come into play momentarily at the top of expansions, and not in the form of some kind of equilibration via prices, but as a more or less violent external interruption in the dynamics of aggregate demand. It is more or less always true, that if you ask why is output higher than it was last period, the answer is that someone decided to increase their expenditure. 

Third, I like that the article is picking up the conversation from the postwar Keynesians like Harrod, Kaldor and Hicks, and more recent structural-Keynesian approaches. The fundamental units of the argument are the aggregate behavior of firms and households, without the usual crippling insistence on reducing everything to a problem of intertemporal optimization. (The question of microfoundations gets a one-sentence footnote, which is about what it deserves.) Without getting into these methodological debates here, I think this kind of structuralist approach is one of the most productive ways forward for positive macroeconomic theory. Admittedly, almost all the other papers in this issue of ROKE are coming from more or less the same place, but I single out Fazzari for praise here because he's a legitimate big-name economist -- his best known work was coauthored with Glenn Hubbard. (Yes, that Glenn Hubbard.)

Fourth, I like the paper's notion of economies having different regimes, some of persistently excess demand, some persistent demand shortfalls. When I was talking about this paper with Arjun the other day he asked, very sensibly, what's the relevance to our current situation. My first response was not much, it's more theoretical. But it occurs to me now that the mainstream model (often implicit) of fluctuations around a supply-determined growth path is actually quite important to liberal ideas about fiscal policy. The idea that a deep recession now will be balanced by a big boom sometime in the future underwrites the idea that short-run stimulus should be combined with a commitment to long-run austerity. If, on the other hand, you think that the fundamental parameters of an economy can lead to demand either falling persistently behind, or running persistently ahead, of supply constraints, then you are more likely to think that a deep recession is a sign that fiscal policy is secularly too tight (or investment secularly too low, etc.) So the current relevance of the Fazzari paper is that if you prefer their vision to the mainstream's, you are more likely to see the need for bigger deficits today as evidence of a need for bigger deficits forever.

Finally, on a more meta level, I share the implicit vision of capitalism not as a single system in (or perhaps out of) equilibrium, but involving a number of independent processes which sometimes happen to behave consistently with each other and sometimes don't. In the Harrod story, it's demand-driven output and the productive capacity of the economy, and population growth in particular; one could tell the same story about trade flows and financial flows, or about fixed costs and the degree of monopoly (as Bruce Wilder and I were discussing in comments). Or perhaps borrowing and interest rates. In all cases these are two distinct causal systems, which interact in various ways but are not automatically balanced by any kind of price or equivalent mechanism. The different systems may happen to move together in a way that facilitates smooth growth; or they may move inconsistently, which will bring various buffers into play and, when these are exhausted, lead to some kind of crisis whose resolution lies outside the model.

A few points, not so much of criticism, as suggestions for further development.

First, a minor point -- the assumption that expectations adjust in the same direction as errors is a bit trickier than they acknowledge. I think it's entirely reasonable here, but it's clearly not always valid and the domain over which it applies isn't obvious. If for instance the evolution of output is believed to follow a process like yt = c + alpha t + et, then unusually high growth in one period would lead to expectations of lower growth in the next period, not higher as Fazzari et al assume. And of course to the extent that such expectations would tend to stabilize the path of output, they would be self-fulfilling. (In other words, widespread belief in the mainstream view of growth will actually make the mainstream view more true -- though evidently not true enough.) As I say, I don't think it's a problem here, but the existence of both kinds of expectations is important. The classic historical example is the gold standard: Before WWI, when there was a strong expectation that the gold link would be maintained, a fall in a country's currency would lead to expectations of subsequent appreciation, which produced a capital inflow that in fact led to the appreciation;  whereas after the war, when devaluations seemed more likely, speculative capital flows tended to be destabilizing.

Two more substantive points concern supply constraints. I think it's a strength, not a weakness of the paper that it doesn't try to represent supply constraints in any systematic way, but just leaves them exogenous. Models are tools for logical argument, not toy train sets; the goal is to clarify a particular set of causal relationships, not to construct a miniature replica of the whole economy. Still, there are a couple issues around the relationship between rising demand and supply constraints that one would like to develop further.

First, what concretely happens when aggregate expenditure exceeds supply? It's not enough to just say "it can't," in part because expenditure is in dollar terms while supply constraints represent real physical or sociological limits. As Fazzari et al. acknowledge, we need some Marx with our Keynes here -- we need to bring in falling profits as a key channel by which supply constraints bind. [4] As potential output is approached, there's an increase in the share claimed by inelastically-supplied factors, especially labor, and a fall in the share going to capital. This is the classic Marxian cyclical profit squeeze, though in recent cycles it may be the rents claimed by suppliers of oil and "land" in general, as opposed to wages, that is doing much of the squeezing. But in any case, a natural next step for this work would be to give a more concrete account of the mechanisms by which supply constraints bind. This will also help clarify why the transitions from expansion to recession are so much more abrupt than the transitions the other way. (Just as there are no mini-recessions, neither are there anti-crises.) The pure demand story explains why output cannot rise stably on the full employment trajectory, but must either rise faster or else fall; but on its own it's essentially symmetrical and can't explain why recessions are so much steeper and shorter than expansions. Minsky-type dynamics, where a fall in output means financial commitments cannot be met, must also play a role here.

Second, how does demand-driven evolution of output affect growth of supply? They write, 

while in our simple model the supply-side path is assumed exogenous, it is easy to posit realistic economic channels through which the actual demand-determined performance of the economy away from full employment affects conditions of supply. The quantity and productivity of labor and capital at occasional business-cycle peaks will likely depend on the demand-determined performance of the economy in the normal case in which the system is below full employment.

I think this is right, and a very important point to develop. There is increasing recognition in the mainstream of the importance of hysteresis -- the negative effects on economic potential of prolonged unemployment. There's little or no discussion of anti-hysteresis -- the possibility that inflationary booms have long-term positive effects on aggregate supply. But I think it would be easy to defend the argument that a disproportionate share of innovation, new investment and laborforce broadening happens in periods when demand is persistently pushing against potential. In either case, the conventional relationship between demand and supply is reversed -- in a world where (anti-)hysteresis is important, "excessive" demand may lead to only temporarily higher inflation but permanently higher employment and output, and conversely.

Finally, obsessive that I am, I'd like to link this argument to Leijonhufvud's notion of a "corridor of stability" in capitalist economies, which -- though Leijonhufvud isn't cited -- this article could be seen as a natural development of. His corridor is different from this one, though -- it refers to the relative stability of growth between crises. The key factor in maintaining that stability is the weakness of the link between income and expenditure as long as changes in income remain small. Within some limits, changes in the income of households and firms do not cause them to revise their beliefs about future income (expectations are normally fairly inelastic), and can be buffered by stocks of liquid assets and the credit system. Only when income diverges too far from its prior trajectory do expectations change -- often discontinuously -- and, if the divergence is downward, do credit constraints being to bind. If it weren't for these stabilizing factors, capitalist growth would always, and not just occasionally, take the form of explosive bubbles. 

Combining Leijonhufvud and Fazzari et al., we could envision the capitalist growth path passing through concentric bands of stability and instability. The innermost band is Leijonhufvud's corridor, where the income-expenditure link is weak. Outside of that is the band of Harrodian instability, where expectations are adjusting and credit constraints bind. That normal limits of that band are set, at least over most of the postwar era, by active stabilization measures by the state, meaning in recent decades monetary policy. (The signature of this is that recoveries from recessions are very rapid.) Beyond this is the broader zone of instability described by the Fazzari paper -- though keeping the 1930s in mind, we might emphasize the zero lower bound on gross investment a bit more, and autonomous spending less, in setting the floor of this band. And beyond that must be a final zone of instability where the system blows itself to pieces.

Bottom line: If heterodox macroeconomic theory is going to move away from pure critique (and it really needs to) and focus on developing a positive alternative to the mainstream, articles like this are a very good start.

[1] It's unfortunate that no effort has been made to make ROKE content available online. Since neither of the universities I'm affiliated with has a subscription yet, it's literally impossible for me -- and presumably you -- to see most of the articles. I imagine this is a common problem for new journals. When I raised this issue with one of the editors, and asked if they'd considered an open-access model, he dismissed the idea and suggested I buy a subscription -- hey, it's only $80 for students. I admit this annoyed me some. Isn't it self-defeating to go to the effort of starting a new journal and solicit lots of great work for it, and then shrug off responsibility for ensuring that people can actually read it?

[2] It's not a straightforward question what exactly is growing in economic growth. When I talk about demand dynamics, I prefer to use the generic term "activity," as proxied by a variety of measures like GDP, employment, capacity utilization, etc. (This is also how NBER business-cycle dating works.) But here I'll follow Fazzari et al. and talk about output, presumably the stuff measured by GDP.

[3] See for instance this post from David Altig at the Atlanta Fed, from just yesterday: 

Forecasters, no matter where they think that potential GDP line might be, all believe actual GDP will eventually move back to it. "Output gaps"—the shaded area representing the cumulative miss of actual GDP relative to its potential—simply won't last forever. And if that means GDP growth has to accelerate in the future (as it does when GDP today is below its potential)—well, that's just the way it is.

Here we have the consensus with no hedging. Everyone knows that long-run growth is independent of aggregate demand, so slower growth today means faster growth tomorrow. That's "nature," that's just the way it is.

[4] This fits with the story in Capitalism Since 1945, still perhaps the first book I would recommend to anyone trying to understand the evolution of modern economies. From the book:

The basic idea of overaccumulation is that capitalism sometimes generates a higher rate of accumulation than can be sustained, and thus the rate of accumulation has eventually to fall. Towards the end of the postwar boom, an imbalance between accumulation and the labor supply led to increasingly severe labor shortage. ... Real wages were pulled up and older machines rendered unprofitable, allowing a faster transfer of workers to new machines. This could in principle have occurred smoothly: as profitability slid down, accumulation could have declined gently to a sustainable rate. but the capitalist system has no mechanism guaranteeing a smooth transition in such circumstances. In the late sixties the initial effect of overaccumulation was a period of feverish growth with rapidly rising wages and prices and an enthusiasm for get-rich-quick schemes. These temporarily masked, but could not suppress, the deterioration in profitability. Confidence was undermined, investment collapsed and a spectacular crash occurred. Overaccumulation gave rise, not to a mild decline in the profit rate, but to a classic capitalist crisis.

I think the Marxist framework here, with its focus on profit rates, complements rather than contradicts the Keynesian frame of Fazzari et al. and its focus on demand. In particular, the concrete mechanisms by which supply constraints operate are much clearer here.