I remember my monetary theory professor using an aggregate demand/supply graph to illustrate supply-side theories of the business cycle, where a supply shock shifts the supply curve to the left. All else equal, a negative supply shock will lead to an increase in the price level — the same amount of money chasing less goods. This is how some people interpret Austrian business cycle theory (ABCT): there is a negative supply-side shock to the capital stock. It follows that the price level for capital goods rises. But, the evidence suggests the exact opposite, falling prices in the capital (intermediate) goods sector. That interpretation is wrong. ABCT is a demand-side theory, and it predicts just what the evidence shows, a falling price level for capital goods.

I also discuss what predictions ABCT makes regarding the general price level. The simple answer: none. This is why the ABCT cannot explain the depth of a recession on its own. I make my case in the second part of the post.

If you think that Hayek’s theory is about a supply-shock, read “The Maintenance of Capital.” The article presents a theory of the value of the heterogeneous capital stock. It’s related to Hayek’s business cycle research, in that it clearly frames the issue in the context of aggregate demand. Note his discussion of “capital consumption.” Capital consumption is not the same thing as a supply-side shock to the capital stock. Remember, the value of the capital stock is imputed (derived) from the final product. A rise in the price of an input is caused by an increase in demand for that input’s output. A fall in the demand for the final product, leads to a fall in the value of those inputs — capital consumption. This is important to keep in mind, because this is one of the basic parts to ABCT.

Let’s call an economy “neutral” when the allocation is optimal (don’t worry about frictions and imperfections). Picture an economy as a production possibilities frontier (PPF), with capital goods on one axis and consumer goods on the other. The PPF represents potential mixtures of output, given some given amount of resources. Not all points on the PPF are equally valuable. The neutral economy produces where the opportunity cost is lowest, which is a specific point on the PPF. Essentially, ABCT predicts that an excess supply of money will cause an economy to become non-neutral, by producing on some other point along (or inside) the PPF. This is shown in the graphic below, where the PPF is on the right — consumer goods on the y-axis and capital (or producer) goods on the x-axis. There are two marked places on the PPF; the uppermost circle is the original mix of output, and the lower circle is the new mix of output.

(Don’t worry about the Hayekian triangle on the left panel.)

Forget about central banks and interest rates, and focus on an excess supply of money. Hayek and Mises believed excess supplies of money to be non-neutral. Specifically, they thought excess supplies of money changed the prices of capital goods relative to those of consumer goods. The stylized process by which this happens is that new money is introduced through the loanable funds market, as banks extend loans. That borrowed money is used to buy certain inputs, raising the price of those inputs, and thus the profitability of producing them. The economy moves towards producing somewhere lower on our PPF curve, above (the second point on the curve). This means less consumer good output, since more resources are being used to manufacture intermediate (capital) goods. But, the level of consumption remains the same, so as the supply of consumers’ good falls, their price increases. This sets off a process of reversion, where the structure of production has to re-adapt to society’s time preference (intertemporal equilibrium).

Where is the shock to the capital stock? As amount of current inputs going into the production of future inputs increases, it changes the nature of capital. If the value of capital is imputed from the final product, and the final product capital is being used for changes, then the value of the capital stock will change. The excess supply of money, by raising the price of inputs, creates “false” profits. To keep it simple, “false” profits are non-neutral. These profits will make the new structure of production seem of high value. But, the reversion process corrects this, and there is a change in the pattern of demand. The investment during the boom is “malinvestment,” and the capital stock loses much of its value (it’s consumed), by virtue of the fact that the “false” demand for its output collapses.

Note that the prediction is a fall in the value of the capital stock. The physical stock of capital remains the same. The prices of capital goods, however, collapse. The type of inputs produced by the boom-time structure of production are not as useful as they first seemed. The range of productive uses narrows, and if the capital is highly specific it might become completely useless (Hayek makes this point explicitly in Prices and Production, and references the debate on idle resources).

To put the same point differently, imagine a supply/demand graph. The price of a capital good is decided at the margin at which the supply and demand curves meet. ABCT predicts that the demand curve will shift to the right during the boom, and then to the left during the process of reversion. Thus, the bust coincides with a falling price level for capital goods. The supply-side shock, just to be able to compare and contrast, predicts that the bust coincides with a leftward shift of the supply curve, or an increase in the price level for capital goods. The intuition behind that process is that as the amount of a type of capital decreases, the least valuable end that last input is useful towards increases in value (since there is less capital, there are less ends that can be satisfied — and, optimally, the most valued ends are satisfied first). This is not what ABCT predicts. Rather, ABCT says that, during the bust, the least valued end will decrease in value, because, as it turns out, what producers thought were highly valued ends were just distorted profit signals, caused by an excess supply of money.

The theory fits the empirical evidence, at least in this respect,

What about the general price level (consumers’ + producers’ goods)? ABCT is somewhat indeterminate in this regard, because capital consumption occurs while the price of consumers’ goods increases. It’s also ambiguous whether the excess supply of money will end through a rise in the price level, or through some kind of aggregate reflux mechanism. What brings about the primary effects of the ABCT are not changes in the money stock, but changes in relative prices. To explain a decline in the general price level, Austrians usually employ another theory, typically referred to as “secondary deflation.” Because this is no longer really within the scope of the ABCT, Austrians are somewhat vague on this point. But, I think this point is worth discussing, because it shows that ABCT most likely cannot explain a major business cycle on its own.

Rothbard provides an entire section (pp. 14–19) to explaining secondary deflation in America’s Great Depression. He employs a very strict quantity theorist definition of inflation/deflation: an increase/decrease in the money supply (although, I’m not sure this is consistent with some of the causes of deflation he discusses). Some of the causes he gives assume a gold standard, relevant then, but not now. Still, I think they can be generalized. He cites an outflow of gold (or, more broadly, let’s call it capital), forcing banks to contract their balance sheets. He also cites debt liquidation, where credit simply cannot be repaid. Finally, a third force is the increase in the demand for money. The deflationary process is, strictly speaking, separate from the process described by ABCT; related to it, but not directly. Rothbard considers the deflationary process beneficial. In the preface to “Monetary Theory and the Trade Cycle,” Hayek also distinguishes deflation from the process described by ABCT, but writes that “an indefinite continuation of that deflation would do inestimable harm.”

There are multiple margins to judge deflation on. Rothbard’s point, which is valid, is that what matters are relative prices, not general prices, so that deflation doesn’t necessarily cut into profits — especially if capital good prices fall faster than consumer good prices (which is empirically true). I will come back to this shortly. Other channels through which deflation may not be beneficial include those akin to Fisher’s theory of debt deflation. A New Keynesian model will also tell you that a non-inflationary environment forgoes the benefit of inflation to reduce the demand for money, if we are in a liquidity trap, where interest-bearing assets and money are equally attractive, because of low interest rates. I’m not going to comment on the validity of these theories. They are nevertheless worth considering, and I will say why that is below.

Debt deflation and liquidity traps aside, knowing why Rothbard is somewhat wrong is important. Note a claim he makes on the height of unemployment caused by an Austrian business cycle,

Since factors must shift from the higher to the lower orders of production, there is inevitable “frictional” unemployment in a depression, but it need not be greater than unemployment attending any other large shift in production. In practice, unemployment will be aggravated by the numerous bankruptcies, and the large errors revealed, but it still need only be temporary.

— America’s Great Depression, p. 14.

This is, by the way, the exact claim Paul Krugman makes in his criticism of ABCT, what he calls the “hangover theory.” The initial boom period requires substantial capital readjustment, as well, but during this period the unemployment rate is relatively low — either around its “natural” level (~4–5 percent), or below. I think the critique is not as strong as some make it out to be, because the bust is a sudden change in relative demand, with significant capital consumption. During the boom, there is competing demand for consumer and capital goods, so one sector doesn’t necessarily suddenly become unprofitable. The shift in the allocation of labor is much less painful during the boom. Still, Krugman (and Rothbard) have a point: ABCT cannot explain the depth of unemployment very well.1 You need an additional story, and the scapegoat many Austrians like is government, bad supply-side policy and regime uncertainty. But, blaming government is not always right.2

Explaining the direction the general price level moves in is relevant to explaining the depth of unemployment. Putting debt deflation and liquidity traps aside, deflation is good if it’s neutral. If the demand for money increases and deflation is non-neutral, the unemployment rate and the output gap will grow. Assume the money stock at time t is M 1 , but the demand for money at time t+1 calls for a stock equal to M 2 . If the supply of money doesn’t increase, there will be a demand shortage. There will be people who want to increase their cash balances by selling non-money assets, including labor and goods/services. But, there isn’t enough money to meet their demand for it. If deflation is neutral, a falling price level will cause a falling demand for money. If deflation is not neutral, the demand for money remains the same there is a shortage of money, and therefore of demand, and trade that would have taken place does not — output falls. Deflation can be non-neutral if some key prices don’t fall to clear the market, including the price of labor and, perhaps, other capital goods that are heavily complimentary to labor. This is monetary (dis)equilibrium theory. You need this theory to explain the depth of the recession.3

Austrian business cycle theory does not offer us ideas on the direction the general price level takes during a bust. Empirically, deflation is the norm. ABCT cannot explain this deflation, except through use of alternative theories. Further, while the ABCT explains the boom and the direct causes of the bust, it cannot explain other elements of the bust that are caused by confounding factors. But, ABCT definitely does not predict an increase in the price level of capital goods, which is what would happen in a supply-side shock. Rather, it predicts declining capital good prices, which fits the evidence.

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Notes:

1. I discussed a similar criticism in an August 2011 article, “Rethinking Depression Economics.” I think that much of my insight is valuable, but, at the time, I had not considered the role of monetary equilibrium to the extent I should have.

2. Bad supply-side policy can explain a lot of unemployment. The high unemployment of the Great Depression is explained in large part by bad supply-side policy. Alternative theories should be seen as complimentary. Look at the difference in unemployment between Spain and the United States, both of which have similar output gaps. Spain is an example of bad supply-side policy. The U.S., however, is an example of bad demand-side policy. As the unemployment rate falls, the output gap remaining equal, supply-side theories of unemployment have less explanatory power.

3. Hayek understood this. Apart from his comments on the negative effects of deflation, see “The Gold Problem” (published in Good Money, Part I) and “Monetary Nationalism and Monetary Stability.” I think he realized the power of Hawtreyian (?) explanations of the Great Depression, which focused on international gold flows and reserve hoarding by part of central banks. He wanted to synthesize these theories with his own.