Last Friday, Scott Sumner posted a diatribe against the IS-LM triggered by a set of slides by Chris Foote of Harvard and the Boston Fed explaining how the effects of monetary policy can be analyzed using the IS-LM framework. What really annoys Scott is the following slide in which Foote compares the “spending (aka Keynesian) hypothesis” and the “money (aka Monetarist) hypothesis” as explanations for the Great Depression. I am also annoyed; whether more annoyed or less annoyed than Scott I can’t say, interpersonal comparisons of annoyance, like interpersonal comparisons of utility, being beyond the ken of economists. But our reasons for annoyance are a little different, so let me try to explore those reasons. But first, let’s look briefly at the source of our common annoyance.
The “spending hypothesis” attributes the Great Depression to a sudden collapse of spending which, in turn, is attributed to a collapse of consumer confidence resulting from the 1929 stock-market crash and a collapse of investment spending occasioned by a collapse of business confidence. The cause of the collapse in consumer and business confidence is not really specified, but somehow it has to do with the unstable economic and financial situation that characterized the developed world in the wake of World War I. In addition there was, at least according to some accounts, a perverse fiscal response: cuts in government spending and increases in taxes to keep the budget in balance. The latter notion that fiscal policy was contractionary evokes a contemptuous response from Scott, more or less justified, because nominal government spending actually rose in 1930 and 1931 and spending in real terms continued to rise in 1932. But the key point is that government spending in those days was too meager to have made much difference; the spending hypothesis rises or falls on the notion that the trigger for the Great Depression was an autonomous collapse in private spending.
But what really gets Scott all bent out of shape is Foote’s commentary on the “money hypothesis.” In his first bullet point, Foote refers to the 25% decline in M1 between 1929 and 1933, suggesting that monetary policy was really, really tight, but in the next bullet point, Foote points out that if monetary policy was tight, implying a leftward shift in the LM curve, interest rates should have risen. Instead they fell. Moreover, Foote points out that, inasmuch as the price level fell by more than 25% between 1929 and 1933, the real value of the money supply actually increased, so it’s not even clear that there was a leftward shift in the LM curve. You can just feel Scott’s blood boiling:
What interests me is the suggestion that the “money hypothesis” is contradicted by various stylized facts. Interest rates fell. The real quantity of money rose. In fact, these two stylized facts are exactly what you’d expect from tight money. The fact that they seem to contradict the tight money hypothesis does not reflect poorly on the tight money hypothesis, but rather the IS-LM model that says tight money leads to a smaller level of real cash balances and a higher level of interest rates.
To see the absurdity of IS-LM, just consider a monetary policy shock that no one could question—hyperinflation. Wheelbarrows full of billion mark currency notes. Can we all agree that that would be “easy money?” Good. We also know that hyperinflation leads to extremely high interest rates and extremely low real cash balances, just the opposite of the prediction of the IS-LM model. In contrast, Milton Friedman would tell you that really tight money leads to low interest rates and large real cash balances, exactly what we do see.
Scott is totally right, of course, to point out that the fall in interest rates and the increase in the real quantity of money do not contradict the “money hypothesis.” However, he is also being selective and unfair in making that criticism, because, in two slides following almost immediately after the one to which Scott takes such offense, Foote actually explains that the simple IS-LM analysis presented in the previous slide requires modification to take into account expected deflation, because the demand for money depends on the nominal rate of interest while the amount of investment spending depends on the real rate of interest, and shows how to do the modification. Here are the slides:
Thus, expected deflation raises the real rate of interest thereby shifting the IS curve to the left while leaving the LM curve where it was. Expected deflation therefore explains a fall in both nominal and real income as well as in the nominal rate of interest; it also explains an increase in the real rate of interest. Scott seems to be emotionally committed to the notion that the IS-LM model must lead to a misunderstanding of the effects of monetary policy, holding Foote up as an example of this confusion on the basis of the first of the slides, but Foote actually shows that IS-LM can be tweaked to accommodate a correct understanding of the dominant role of monetary policy in the Great Depression.
The Great Depression was triggered by a deflationary scramble for gold associated with the uncoordinated restoration of the gold standard by the major European countries in the late 1920s, especially France and its insane central bank. On top of this, the Federal Reserve, succumbing to political pressure to stop “excessive” stock-market speculation, raised its discount rate to a near record 6.5% in early 1929, greatly amplifying the pressure on gold reserves, thereby driving up the value of gold, and causing expectations of the future price level to start dropping. It was thus a rise (both actual and expected) in the value of gold, not a reduction in the money supply, which was the source of the monetary shock that produced the Great Depression. The shock was administered without a reduction in the money supply, so there was no shift in the LM curve. IS-LM is not necessarily the best model with which to describe this monetary shock, but the basic story can be expressed in terms of the IS-LM model.
So, you ask, if I don’t think that Foote’s exposition of the IS-LM model seriously misrepresents what happened in the Great Depression, why did I say at beginning of this post that Foote’s slides really annoy me? Well, the reason is simply that Foote seems to think that the only monetary explanation of the Great Depression is the Monetarist explanation of Milton Friedman: that the Great Depression was caused by an exogenous contraction in the US money supply. That explanation is wrong, theoretically and empirically.
What caused the Great Depression was an international disturbance to the value of gold, caused by the independent actions of a number of central banks, most notably the insane Bank of France, maniacally trying to convert all its foreign exchange reserves into gold, and the Federal Reserve, obsessed with suppressing a non-existent stock-market bubble on Wall Street. It only seems like a bubble with mistaken hindsight, because the collapse of prices was not the result of any inherent overvaluation in stock prices in October 1929, but because the combined policies of the insane Bank of France and the Fed wrecked the world economy. The decline in the nominal quantity of money in the US, the great bugaboo of Milton Friedman, was merely an epiphenomenon.
As Ron Batchelder and I have shown, Gustav Cassel and Ralph Hawtrey had diagnosed and explained the causes of the Great Depression fully a decade before it happened. Unfortunately, whenever people think of a monetary explanation of the Great Depression, they think of Milton Friedman, not Hawtrey and Cassel. Scott Sumner understands all this, he’s even written a book – a wonderful (but unfortunately still unpublished) book – about it. But he gets all worked up about IS-LM.
I, on the other hand, could not care less about IS-LM; it’s the idea that the monetary cause of the Great Depression was discovered by Milton Friedman that annoys the [redacted] out of me.
UPDATE: I posted this post prematurely before I finished editing it, so I apologize for any mistakes or omissions or confusing statements that appeared previously or that I haven’t found yet.
