Archive for the 'Scott Sumner' Category

Why Theories of National Income Based on Accounting Identities Are Nonsensical and Error-Ridden, Part II

In this installment of my series on Richard Lipsey’s essay “The Foundations of the Theory of National Income,” I am going to focus on a single issue: what inferences about reality are deducible from a definition about the meaning of the terms used in a scientific theory? In my first installment I listed seven common statements about the basic Keynesian income-expenditure model that are found in most textbooks. The first concerned the confusion between the equality of investment and saving (or between income and expenditure) as an equilibrium condition and a definitional identity. Interpreting the equality of savings and investment as an identity essentially means collapsing the entire model onto the 45-degree line and arbitrarily choosing some point on the 45-degree line as the solution of the model.

That nonsensical interpretation of the simple Keynesian cross is obviously unsatisfactory, so, in an effort to save both the definitional identity of savings and investment and the equality of investment and savings as an equilibrium condition, the textbooks have introduced a distinction between ex ante and ex post in which savings and investment are defined to be identically equal ex post, but planned (ex ante) savings may differ from planned (ex ante) investment, their equality being the condition for equilibrium.

Now, to be fair, it is perfectly legitimate to define an equilibrium in terms of plan consistency, and to say that the inconsistency of the plans occasions a process of readjustment in the plans, and that it is the readjustment in the plans which leads to a new equilibrium. The problem with the textbook treatment is that it draws factual inferences about the adjustment process to a disequilibrium in which planned saving is not equal to planned investment from the definitional identity between ex post savings and ex post investment. In particular, the typical textbook treatment infers that in a disequilibrium with planned savings not equal to planned investment, the adjustment process is characterized by unplanned positive or negative investment (inventory accumulation or decumulation) corresponding to the gap between planned savings and planned investment. Identifying a gap between planned saving and planned investment with unplanned inventory accumulation or decumulation, as textbook treatments of the income expenditure model typically do, is logically unfounded.

Again, I want to be careful, I am not saying that unplanned inventory accumulation or decumulation could not occur in response to a difference gap between planned savings and planned investment, or even that such unplanned inventory accumulation or decumulation is unlikely to occur. What I am saying is that the definitional identity between ex post savings and ex post investment does not imply that such inventory accumulation or decumulation takes place and certainly not that the amount by which inventories change is necessarily equal to the gap between planned savings and planned investment.

Richard Lipsey made the key point in his comment on my previous post:

The main issue in this whole discussion is, I think, can we use a definitional identity to rule out an imaginable state of the universe. The answer is “No”, which is why Keynes was wrong. The definitional identity of S ≡ I tells us nothing about what will happen if agents wish to save a different amount from what agents wish to invest.

Here is how Lipsey put it in his 1972 essay:

The error in this interpretation lies in the belief that the identity EY can tell us what can and cannot happen in the world. If it were possible that a definitional identity could rule out certain imaginable events, then such a definitional identity would be an informative statement having empirical content! If it is a genuine definitional identity (which follows from our use of words and is compatible with all states of the universe) then it is only telling us that we are using E and Y to refer to the same thing, and this statement no more allows us to place restrictions on what happens in the world than does the statement that we are not using E and Y to refer to the same thing.

Lipsey illustrated the problem using the simple Keynesian cross diagram. To make the discussion a bit easier to follow, I am going to refer to my own slightly altered version (using a specific numerical example) of the familiar diagram. Setting investment (I) equal to 100 and assuming the following consumption function

C = 25 + .5Y

We can easily solve for an equilibrium income of 250 corresponding to the intersection of the expenditure function with the 45-degree line.

lipsey_45_degreeWhat happens if we posit that the system is at a disequilibrium point, say Y = 400. The usual interpretation is that at Y = 400, planned (ex ante) investment is less than savings and planned (ex ante) expenditure is less than income. Because, actual (ex post) investment is identically equal to savings and because actual (ex post) expenditure is identically equal to income, unplanned investment must occur to guarantee that the investment-savings identity is satisfied. The amount of unplanned investment is shown on the graph as the vertical distance between the expenditure function (E(Y)) at Y = 400 and the 45-degree line at Y = 400. This distance is shown in my diagram as the vertical distance between the points a and b on the diagram, and it is easy to check that the distance corresponds to a value of 75.

So the basic textbook interpretation of the Keynesian cross is using the savings-investment identity to derive a proposition about the behavior of the economy in disequilibrium. It is saying that an economy in disequilibrium with planned investment less than planned savings adjusts to the disequilibrium through unplanned inventory accumulation (unplanned investment) that exactly matches the difference between planned saving and planned investment. But it is logically impossible for a verbal identity (between savings and investment) — an identity that can never be violated in any actual state of the world — to give us any information about what actually happens in the world, because whatever happens in the world, the identity will always be satisfied.

Recall erroneous propositions 2, 3 and 4, listed in part I of this series:

2 Although people may try to save different amounts from what people try to invest, savings can’t be different from investment; realized (ex post) savings necessarily always equals realized (ex post) investment.

3 Out of equilibrium, planned savings do not equal planned investment, so it follows from (2) that someone’s plans are being disappointed, and there must be either unplanned savings or dissavings, or unplanned investment or disinvestment

4 The simultaneous fulfilment of the plans of savers and investors occurs only when income is at its equilibrium level just as the plans of buyers and sellers can be simultaneously fulfilled only at the equilibrium price.

If realized (ex post) savings necessarily always equals realized (ex post) investment, that equality is the result of how we have chosen to define those terms, not because of people actually are behaving, e.g., by unwillingly accumulating inventories or failing to save as much as they had intended to. However people behave, the identity between savings and investment will be satisfied. And whether savers and investors are able to fulfill their plans or are unable to do so cannot possibly be inferred from a definition that says that savings and investment mean the same thing.

In several of his comments on my recent posts, Scott Sumner has cited the professional consensus that savings and investment are defined to be equal. I am not so sure that there is really a consensus on that point, because I don’t think that most economists have thought carefully about what the identity actually means. But even if there is a consensus that savings is identical to investment, no empirical implication follows from that definition. But typical textbook expositions, and I think even Scott himself when he is not being careful, do use the savings-investment identity to make inferences about what actually happens in the real world.

In the next installment, I will go through a numerical example that shows, based on a simple lagged adjustment between consumption and income (household consumption in this period being a function of income in the previous period), that planned savings and planned investment can be realized and unequal in the transition from one equilibrium to another.

PS I apologize for having been unable to respond to a number of comments to previous posts. I will try to respond in the next day or two.

Savings and Investment Aren’t the Same Thing and There’s No Good Reason to Define them as Such

Scott Sumner responded to my previous post criticizing his use of the investment-savings identity in a post on the advantages NGDI over NGDP, and to my posts from three years ago criticizing him for relying on the savings-investment identity. Scott remains unpersuaded by my criticism. I want to understand why my criticism appears so ineffective, so I’m going to try to understand Scott’s recent response, which begins by referring to economics textbooks. Since it is well documented that economics textbooks consistently misuse the savings-investment identity, it would not be surprising to find out that the textbooks disagree with my position (though Scott doesn’t actually cite chapter and verse).

Economics textbooks define savings as being equal to investment:

S = I

To say that something is equal to investment doesn’t seem to me to be much of a definition of whatever that something is. So Scott elaborates on the definition.

This means savings is defined as the funds used for investment.

OK, savings are the funds used for investment. Does that mean that savings and investment are identical? Savings are funds accruing (unconsumed income measured in dollars per unit time); investments are real physical assets produced per unit time, so they obviously are not identical physical entities. So it is not self-evident – at least not to me — how the funds for investment can be said to be identical to investment itself. The two don’t seem to be self-evidently identical to Scott either, because he invokes another identity.

It’s derived from another identity, which says that in a closed economy with no government, gross domestic product equals gross domestic income:

GDI = C + S = C + I = GDP

But once again, it is not self-evident that GDI and GDP are identical. Income usually refers to earnings per unit time derived by factors of production for services rendered. Or stated another way, GDI represents the payments per unit time – a flow of money — made by business firms to households. In contrast, GDP could represent either a flow of final output from business firms to households and to other business firms, or the expenditures made by households and business firms to business firms. These two flows of output and expenditure are not identical, though, for the most part, representing two sides of the same transactions, there is considerable overlap. But it is clear that payments made by business firms to households in exchange for factor services rendered are not identical to the expenditures made by households and business firms to business firms for final output.

Bill Woolsey in a post commenting on my post and Scott’s earlier post to which I responded attempts to explain why these two flows are identical:

In a closed private economy, saving must equal investment. This is a matter of definition. Saving is defined as income less consumption. All output is defined as either being consumer goods or capital goods. Consumption is spending on consumer goods and investment is spending on capital goods. All expenditure is either on consumer goods or capital goods. Since income equals expenditure, and consumption is itself, then income less consumption must equal expenditure less consumption. By the definition of saving and investment, saving and investment are always equal.

I guess someone might think that is all insightful, but it comes down to saying that purchases equals sales.

Bill is very careful in saying that savings is defined as income less consumption, and all output is defined as either being consumer goods or capital goods, and all consumption is (presumably also by definition) spending (aka expenditure) on consumer goods and investment is spending (aka expenditure) on capital goods. So all expenditures are made either on consumer goods or on capital goods. Then Bill concludes that by the definition of savings and investment, savings and investment are always equal (identical), because consumption is itself and income equals expenditure. But Bill does not say why income equals expenditure. Is it because income and expenditure are identical? But, as I just pointed out, it is not self-evident that income (defined as the earnings accruing to households per unit time) and expenditure (defined as the revenues accruing to business firms in payment for final output produced per unit time) are identical.

Now perhaps Bill (no doubt with Scott’s concurrence) is willing to define expenditure as being equal to income, but why is it necessary to define income and expenditure, which don’t obviously refer to the same thing, as being equal by definition? I mean we know that the Morningstar is Venus, but that identity was not established by definition, but by empirical observation. What observation establishes that income (the earnings of factors of production per unit time) and expenditure (revenues accruing to business firms for output sold per unit time) are identical? As Scott has himself noted on numerous occasions, measured NGDI can differ and has frequently differed substantially from measured NGDP.

It is certainly true that we are talking about a circular flow: expenditure turns into income and income into expenditure. Expenditures by households and by business firms for the final output produced by business firms generate the incomes paid by business firms to households and the income paid to households provides the wherewithal for households to pay for final output. But that doesn’t mean that income is identical to expenditure. Chickens generate eggs and eggs generate chickens. That doesn’t mean that a chicken is identical to an egg.

Then Scott addresses my criticism:

David Glasner doesn’t like these definitions, but for some reason that I haven’t been able to figure out he doesn’t say that he doesn’t like the definitions, but rather he claims they are wrong. But the economics profession is entitled to define terms as they wish; there is no fact of the matter. In contrast, Glasner suggests that my claim is only true as some sort of equilibrium condition:

It’s not a question of liking or not liking, but one ought to be parsimonious in choosing definitions. Is there any compelling reason to insist on defining expenditure to be the same as income? On the contrary, as far as I can tell, there is a decent prima facie case to be made that expenditure and income refer to distinct entities, and are not just different names for the same entity. Perhaps there is some theoretical advantage to defining expenditure and income to be the same thing. If so, I have yet to hear what it is. On the contrary, there is a huge theoretical disadvantage to defining income and expenditure to be identical: doing so makes the Keynesian income-expenditure model unintelligible. Come to think of it, perhaps Scott, a self-described hater of the Keynesian cross, likes that definition. But even if you hate a model, you should try to make it as good and as coherent as possible, before rejecting it. This post is already getting too long, so I will save for a separate post a discussion of why defining income and expenditure to be identical makes the Keynesian income-expenditure model, and the loanable funds doctrine, too, for that matter. For now, let me just say that if you insist that the savings-investment equality (or alternatively the income-expenditure equality) is an identity rather than an equilibrium condition, you have drained all the explanatory content out of your model.

Scott objects to this statement from my previous post:

Scott begins by discussing the simplest version of the income-expenditure model (aka the Keynesian cross or 45-degree model), while treating it, as did Keynes, as if it were interchangeable with the national-accounting identities:

In the standard national income accounting, gross domestic income equals gross domestic output. In the simplest model of all (with no government or trade) you have the following identity:

NGDI = C + S = C + I = NGDP (it also applies to RGDI and RGDP)

Because these two variables are identical, any model that explains one will, ipso facto, explain the other.

Here is Scott’s response:

David’s characterization of my views is simply incorrect. And it’s easy to explain why. I hate the Keynesian cross, and think it’s a lousy model, and yet I have no problem with the national income identities, and believe they occasionally help to clarify thinking. The quote he provides does not in any way “discuss” the Keynesian cross model, just as mentioning MV=PY would not be “discussing” the Quantity Theory of Money.

OK, I believe Scott when he says that he’s not a fan of the Keynesian cross, but it was Scott who brought up consumption smoothing in response to a decline in aggregate demand caused by central bank policy. Consumption smoothing is a neo-classical revision of the Keynesian consumption function, so I was just trying to put Scott’s ideas into the context of a familiar model that utilizes the equality of savings and investment to determine equilibrium income. My point was that Scott was positing a decrease in saving and asserting, by way of the savings-investment identity, that investment would necessarily drop by the same amount that saving had dropped. My response was that the savings-investment identity does not allow you to infer by how much investment falls in response to an assumed decrease in savings, because savings and investment are mutually determined within a macroeconomic model. It doesn’t have to be the Keynesian cross, but you need more than an accounting identity and an assumption that savings falls by x to determine what happens to investment.

Scott then makes the following point.

[I]t seems to me that David should not be focusing on me, but the broader profession. If economics textbooks define S=I as an identity, then it’s clear that I’m right. Whether they should define it as an identity is an entirely different question. I happen to think it makes sense, but I could certainly imagine David or anyone else having a different view.

If I am focusing on Scott rather than the broader profession, that simply shows how much more closely I pay attention to Scott than to the broader profession. In this particular case, I think Scott is manifesting a problem that sadly is very widely shared within the broader profession. Second, that Scott shares a problem with the rest of the profession does not establish that Scott is right in the sense that there is any good reason for the profession to have latched on to the savings-investment identity.

In response to my reference to posts from three years ago criticizing him for relying on the savings-investment identity, Scott writes:

I have never in my entire life made any sort of causal claim that relied solely on an identity. In other words, I never did what David claims I did. Like all economists, I may use identities as part of my argument. For instance, if I were to argue that rapid growth in the money supply would increase inflation, and that this would increase nominal interest rates, and that this would increase velocity, I might then go on to discuss the impact on NGDP. In that case I’d be using the MV=PY identity as part of my discussion, but I’d also be making causal arguments based on economic theory. I never rely solely on identities to make a causal claim.

We have a bit of a semantic issue here about what it means to rely on an identity. As I understand him, Scott is asserting that because savings is identical to investment he can make a causal statement about what happens to savings and then rely on the savings-investment identity to infer directly, by substituting the word “investment” for the word “saving” into a causal statement about investment. I don’t accept that the savings-investment identity allows a causal statement about savings to be transformed into a causal statement about investment without further explanation. My claim is that savings and investment are necessarily equal only in equilibrium. A causal statement about savings can’t automatically be transformed into a causal statement about investment without an explanation of how savings and investment were brought into equality in a new equilibrium.

Scott had trouble with my expression of puzzlement at his statement that Keynesians don’t deny that (ex post) less savings leads to less investment. I found that statement so confusing that apparently I wasn’t able to articulate clearly why I thought it was confusing. Let me try a different approach. First, if savings and investment are identical, then less savings can’t lead to less investment, less savings is less investment. A pound is defined as 2.2 kilograms. Does it make sense to reducing my weight in pounds leads to a reduction in my weight in kilograms? Second, if less savings is less investment, what exactly is the qualification “ex post” supposed to signify? Does it make sense to say that ex post if I lost weight in pounds I would lose weight in kilograms, as if I might plan to lose weight in pounds, but not lose weight in kilograms?

In the same post that I cited above, Bill Woolsey makes the following observation:

To say that at the natural interest rate saving equals investment is like saying at the equilibrium price quantity supplied equals quantity demanded. To say that savings always equals investment is like saying that purchases always equals sales by definition.

To compare the relationship between savings and investment to the relationship between purchases and sales is clearly not valid. The definition of the activity called “purchasing” is that a commodity or a service is transferred from a seller to a buyer. Similarly the definition of the activity called “selling” is that a commodity is transferred to a buyer from a seller. The reciprocity between purchasing and selling is inherent in the definition of either activity. But the definition of “saving” does not immediately tell us anything about the activity called “investing.” As Bill concedes in the passage I quoted earlier, the identity between saving and investment must be derived from the supposed identity between income and expenditure. But the definition of “income” does not immediately tell us anything about “expenditure.” Income and expenditure are not two reciprocal sides of the same transaction. When I buy a container of milk, there is a reciprocal relationship between me and the store that has no direct and immediate effect on the relationship between the store and the factors of production used by the store to be able to sell me that container of milk. I don’t deny that there is a relationship, just as there is a relationship between chickens and eggs, but the relationship is not at all like the reciprocal relationship between a buyer and a seller.

UPDATE: (2/18/2015): In a comment to this post, Bill Woolsey points that I did not accurately characterize his post when I said “Bill does not say why income equals expenditure,” by which I meant that he did not say why income is identical to expenditure. If I had been a more careful reader I would have realized that Bill did indeed explain why income is identical to output and output is identical to expenditure, which (by the transitive law) implies that income is identical to expenditure. However, Bill himself actually concedes that the identity between output and expenditure is arrived at only by imputing the value of unsold inventory to the profit of the firm. But this profit is generated not by an actual expenditure of money, it is generated by an accounting convention — a perfectly legitimate accounting convention, but a convention nonetheless. So I continue to maintain that income, defined as the flow of payments to factors of production per unit time, is not identical to either expenditure or to output. Bill also notes that, as Nick Rowe has argued, in a pure service economy in which there were no capital goods or inventories, output would identically equal expenditure. I agree, but only if no services were provided on credit. There would then be a lag between output and the expenditure corresponding to the output. It is precisely the existence of lags between output, expenditure and income that allows for the possibility of non-instantaneous adjustments to changes, thereby creating disequilibrium transitions between one equilibrium and another.

CAUTION Accounting Identity Handle with Care

About three years ago, early in my blogging career, I wrote a series of blog posts (most or all aimed at Scott Sumner) criticizing him for an argument in a blog post about the inefficacy of fiscal stimulus that relied on the definitional equality of savings and investment. Here’s the statement I found objectionable.

Wren-Lewis seems to be . . . making a simple logical error (which is common among Keynesians.)  He equates “spending” with “consumption.”  But the part of income not “spent” is saved, which means it’s spent on investment projects.  Remember that S=I, indeed saving is defined as the resources put into investment projects.  So the tax on consumers will reduce their ability to save and invest.

I’m not going to quote any further from that discussion. If you’re interested here are links to the posts that I wrote (here, here, here, here, here, and this one in which I made an argument so obviously false that, in my embarrassment, I felt like giving up blogging, and this one in which I managed to undo, at least partially, the damage of the self-inflicted wound). But, probably out of exhaustion, that discussion came to an inconclusive end, and Scott and I went on with our lives with no hard feelings.

Well, in a recent post, Scott has again invoked the savings-equals-investment identity, so I am going to have to lodge another protest, even though I thought that, aside from his unfortunate reference to the savings-investment identity, his post made a lot of sense. So I am going to raise the issue one more time – we have had three years to get over our last discussion – hoping that I can now convince Scott to stop using accounting identities to make causal statements.

Scott begins by discussing the simplest version of the income-expenditure model (aka the Keynesian cross or 45-degree model), while treating it, as did Keynes, as if it were interchangeable with the national-accounting identities:

In the standard national income accounting, gross domestic income equals gross domestic output.  In the simplest model of all (with no government or trade) you have the following identity:

NGDI = C + S = C + I = NGDP  (it also applies to RGDI and RGDP)

Because these two variables are identical, any model that explains one will, ipso facto, explain the other.

There is a lot of ground to cover in these few lines. First of all, there are actually three relevant variables — income, output, and expenditure – not just two. Second aggregate income is not really the same thing as consumption and savings. Aggregate income is constituted by the aggregate earnings of all factors of production. However, an accounting identity assures us that all factor incomes accruing to factors of production, which are all ultimately owned by the households providing services to business firms, must be disposed of either by being spent on consumption or by being saved. Aggregate expenditure is different from aggregate income; expenditure is constituted not by the earnings of households, but by their spending on consumption and by the spending of businesses on investment, the purchase of durable equipment not physically embodied in output sold to households or other businesses. Aggregate expenditure is very close to but not identical with aggregate output. They can differ, because not all output is sold, some of it being retained within the firm as work in progress or as inventory. However, in an equilibrium situation in which variables were unchanging, aggregate income, expenditure and output would all be equal.

The equality of these three variables can be thought of as a condition of macroeconomic equilibrium. When a macroeconomic system is not in equilibrium, aggregate factor incomes are not equal to aggregate expenditure or to aggregate output. The inequality between factor incomes and expenditure induces further adjustments in spending and earnings ultimately leading to an equilibrium in which equality between those variables is restored.

So what Scott should have said is that because NGDI and NGDP are equal in equilibrium, any model that explains one will, ipso facto, explain the other, because the equality between the two is the condition for finding a solution to the model. It therefore follows that savings and investment are absolutely not the same thing. Savings is the portion of household earnings from providing factor services that is not spent on consumption. Investment is what business firms spend on plant and equipment. The two magnitudes are obviously not the same, and they do not have to be equal. However, equality between savings and investment is, like the equality between income and expenditure, a condition for macroeconomic equilibrium. In an economy not in equilibrium, savings does not equal investment. But the inequality between savings and investment induces adjustments that, in a stable macroeconomic system, move the economy toward equilibrium. Back to Scott:

Nonetheless, I think if we focus on NGDI we are more likely to be able to think clearly about macro issues.  Consider the recent comment left by Doug:

Regarding Investment, changes in private investment are the single biggest dynamic in the business cycle. While I may be 1/4 the size of C in terms of the contribution to spending, it is 6x more volatile. The economy doesn’t slip into recession because of a fluctuation in Consumption. Changes in Investment drive AD.

This is probably how most people look at things, but in my view it’s highly misleading. Monetary policy drives AD, and AD drives investment. This is easier to explain if we think in terms of NGDI, not NGDP.  Tight money reduces NGDI.  That means the sum of nominal consumption and nominal saving must fall, by the amount that NGDI declines.  What about real income?  If wages are sticky, then as NGDI declines, hours worked will fall, and real income will decline.

So far we have no reason to assume that C or S will fall at a different rate than NGDI. But if real income falls for temporary reasons (the business cycle), then the public will typically smooth consumption.  Thus if NGDP falls by 4%, consumption might fall by 2% while saving might fall by something like 10%.  This is a prediction of the permanent income hypothesis.  And of course if saving falls much more sharply than gross income, investment will also decline sharply, because savings is exactly equal to investment.

First, I observe that consumption smoothing and the permanent-income hypothesis are irrelevant to the discussion, because Scott does not explain where any of his hypothetical numbers come from or how they are related. Based on commenter Doug’s suggestion that savings is ¼ the size of consumption, one could surmise that a 4% reduction in NGDP and a 2% reduction in consumption imply a marginal propensity to consumer of 0.4. Suppose that consumption did not change at all (consumption smoothing to the max), then savings, bearing the entire burden of adjustment, would fall through the floor. What would that imply for the new equilibrium of NGDI? In the standard Keynesian model, a zero marginal propensity to consume would imply a smaller effect on NGDP from a given shock than you get with an MPC of 0.4.

It seems to me that Scott is simply positing numbers and performing calculations independently of any model, and then tells us that the numbers have to to be what he says they are because of an accounting identity. That does not seem like an assertion not an argument, or, maybe like reasoning from a price change. Scott is trying to make an inference about how the world operates from an accounting identity between two magnitudes. The problem is that the two magnitudes are variables in an economic model, and their values are determined by the interaction of all the variables in the model. Just because you can solve the model mathematically by using the equality of two variables as an equilibrium condition does not entitle you to posit a change in one and then conclude that the other must change by the same amount. You have to show how the numbers you have posited are derived from the model.

If two variables are really identical, rather than just being equal in equilibrium, then they are literally the same thing, and you can’t draw any inference about the real world from the fact that they are equal, there being no possible state of the world in which they are not equal. It is only because savings and investment are not the same thing, and because in some states of the world they are not equal, that we can make any empirical statement about what the world is like when savings and investment are equal. Back to Scott:

This is where Keynesian economics has caused endless confusion.  Keynesians don’t deny that (ex post) less saving leads to less investment, but they think this claim is misleading, because (they claim) an attempt by the public to save less will boost NGDP, and this will lead to more investment (and more realized saving.)  In their model when the public attempts to save less (ex ante), it may well end up saving more (ex post.)

I agree that Keynesian economics has caused a lot of confusion about savings and investment, largely because Keynes, who, as a philosopher and a mathematician, should have known better, tied himself into knots by insisting that savings and investment are identical, while at the same time saying that their equality was brought about, not by variations in the rate of interest, but by variations in income. Hawtrey, Robertson, and Haberler, among others, pointed out the confusion, but Keynes never seemed to grasp the point. Textbook treatments of national-income accounting and the simple Keynesian cross still don’t seem to have figured this out. But despite his disdain for Keynesian economics, Scott still has to figure it out, too. The best place to start is Richard Lipsey’s classic article “The Foundations of the Theory of National Income: An Analysis of Some Fundamental Errors” (a gated link is available here).

Scott begins by sayings that Keynesians don’t deny that (ex post) less saving leads to less investment. I don’t understand that assertion at all; Keynesians believe that a desired increase in savings, if desired savings exceeded investment, leads to a decrease in income that reduces saving. But the abortive attempt to increase savings has no effect on investment unless you posit an investment function (AKA an accelerator) that includes income as an independent variable. The accelerator was later added to the basic Keynesian model Hicks and others in order to generate cyclical fluctuations in income and employment, but non-Keynesians like Ralph Hawtrey had discussed the accelerator model long before Keynes wrote the General Theory. Scott then contradicts himself in the next sentence by saying that Keynesians believe that by attempting to save less, the public may wind up saving more. Again this result relies on the assumption of an accelerator-type investment function, which is a non-Keynesian assumption. In the basic Keynesian model investment is determined by entrepreneurial expectations. An increase (decrease) in thrift will be self-defeating, because in the new equilibrium income will have fallen (risen) sufficiently to reduce (increase) savings back to the fixed amount of investment entrepreneurs planned to undertake, entrepreneurial expectations being held fixed over the relevant time period.

I more or less agree with the rest of Scott’s post, but Scott seems to have the same knee-jerk negative reaction to Keynes and Keynesians that I have to Friedman and Friedmanians. Maybe it’s time for both of us to lighten up a bit. Anyway in honor of Scott’s recent appoint to the Ralph Hawtrey Chair of Monetary Policy at the Mercatus Center at George Mason University, I will just close with this quotation from Ralph Hawtrey’s review of the General Theory (chapter 7 of Hawtrey’s Capital and Employment) about Keynes’s treatment of savings and investment as identically equal.

[A]n essential step in [Keynes’s] train of reasoning is the proposition that investment and saving are necessarily equal. That proposition Mr. Keynes never really establishes; he evades the necessity doing so by defining investment and saving as different names for the same thing. He so defines income to be the same thing as output, and therefore, if investment is the excess of output over consumption, and saving is the excess of income over consumption, the two are identical. Identity so established cannot prove anything. The idea that a tendency for investment and saving to become different has to be counteracted by an expansion or contraction of the total of incomes is an absurdity; such a tendency cannot strain the economic system, it can only strain Mr. Keynes’s vocabulary.

Credibility and the Central Bank Balance Sheet

Scott Sumner has been making the argument lately that a central bank with credibility can limit the growth of its balance sheet more effectively than a central bank that is not credible. The context for Scott’s claim is the chronic complaint by QE opponents that the Fed, by doing QE, has dangerously increased the size of its balance sheet, thereby creating an unacceptable risk of future inflation. Scott contends that if the Fed had been more credibly committed to its inflation target of 2%, the Fed would not have needed to create so many dollars in a futile effort to meet its inflation target. In other words, more credibility would mean a smaller balance sheet. That was a clever jujitsu move on Scott’s part, but does his argument really have a basis in economic logic?

The key point here is that the size of a bank’s balance sheet depends on the public’s demand to hold the liabilities of the bank. So for Scott to be right, credibility has to reduce the amount of base money issued by the central bank that the public wants to hold. So, if by credibility we mean the confidence with which the public expects the Fed to meet its announced inflation target, then, when the Fed is undershooting its inflation target so that enhanced credibility would be associated with a rise in expected inflation, enhancing credibility would indeed imply a reduction in the Fed’s balance sheet. However, if the Fed were overshooting its inflation target, enhancing credibility would imply an increase in the Fed’s balance sheet.

The credibility issue has become especially acute after the Swiss National Bank abandoned its peg to the euro last Thursday. To support the peg the Swiss National Bank was committed to buy euros without limit at a price of 1.2 swiss francs per euro, causing the balance sheet of the SNB to expand greatly. The main liability component of a central bank’s balance sheet is the monetary base; the Swiss monetary base has grown from 80bn francs when the peg was adopted in September 2011 to about 400bn francs at present. However, the Swiss monetary base has been in the neighborhood of 400bn francs for over a year, so even assuming that a new wave of demand for swiss francs, based on expectations of a falling euro and capital flight from Russia, had — or was about to — come crashing down on Switzerland, there is no reason to think that the peg had suddenly became unsustainable. Moreover, insofar as the bank was motivated by fears of euro depreciation, the bank could have seamlessly switched from a euro to a dollar peg, which might still be a face-saving way for the bank to reverse course.

So here’s the question: given that there was an international increase in the demand for Swiss francs, if the SNB wanted to limit the increase in the size of its balance sheet, associated with an increase in the international demand for francs, did dropping the euro peg imply a smaller balance sheet than the balance sheet it would have had with the peg maintained? Well, the answer is: it depends. By fooling the markets, and allowing the franc to appreciate by 20% over night, the bank avoided the increased demand for francs that would have occurred had the markets expected the peg to be dropped. So the SNB was able to achieve an unexpected increase in the value of the Swiss franc without encouraging an increase in the demand for francs based on expectations of future appreciation, and to that extent, the SNB was able to reduce the size of its balance sheet.

But another question immediately arises. Now that the franc has appreciated by about 20% after the euro peg was dropped, what will happen to the demand for Swiss francs? The speculative demand for francs based on expected future appreciation has probably been reduced by the sudden appreciation of the franc. However, Switzerland is now facing internal deflation, even if there is no further franc appreciation in foreign exchange markets, as the domestic Swiss price level adjusts to the new higher value of the franc. Oncoming Swiss deflation will increase the expected return to Swiss residents from holding francs while simultaneously reducing the expected return on physical capital in Switzerland, so a substantial shift out of real Swiss assets into cash is likely. Such a shift started immediately last week in the first two days after the peg was dropped, the Swiss stock market falling by about 10 percent, though Swiss equities did make up some of their losses in Monday’s trading. Given an increased Swiss demand to hold francs, the SNB will either have to increase the amount of base money, thereby increasing the size of its balance sheet, or it will have to allow the increased demand for francs to add to deflationary pressure, thereby causing further franc appreciation in the forex markets, attracting further inflows of foreign cash to acquire francs. If the SNB was uncomfortable with the euro peg, the SNB is likely to find out very soon that life without the euro peg or a substitute dollar peg is going to be even more unpleasant.

If your lot in life is to supply the internationally desirable currency of a small open economy – in other words if you are the Swiss National Bank – it is the height of folly to believe that you can place some arbitrary limit on the size of your balance sheet. The size of your balance sheet will ultimately be determined one way or another by the international demand to hold your currency. If you are unwilling to let your balance sheet expand in nominal terms by supplying the amount of cash foreigners demand as they try to exchange their currency for yours, you will only force up the value of your currency, which will make holding your currency even more attractive, at least until the currency appreciation and deflation that you have inflicted on your own economy cause your economy to go down in flames.

As an extended historical postscript, let me just mention the piece that Markus Brunnermeier and Harold James wrote for Project Syndicate, in which they astutely diagnose the political pressures that may have forced the SNB to abandon the euro peg.

The SNB was not forced to act by a speculative run. No financial crisis forced its hand, and, in theory, the SNB’s directorate could have held the exchange rate and bought foreign assets indefinitely. But domestic criticism of the SNB’s large buildup of exchange-rate reserves (euro assets) was mounting.

In particular, Swiss conservatives disliked the risk to which the SNB was exposed. Fearing that eurozone government bonds were unsafe, they agitated to require the SNB to acquire gold reserves instead, even forcing a referendum on the matter. Though the initiative to require a fixed share of gold reserves failed, the prospect of large-scale quantitative easing by the European Central Bank, together with the euro’s recent slide against the dollar, intensified the political pressure to abandon the peg.

Whereas economists have modeled financial attacks well, there has been little study of just when political pressure becomes unbearable and a central bank gives in. The SNB, for example, had proclaimed loyalty to the peg just days before ending it. As a result, markets will now hesitate to believe central banks’ statements about future policy, and forward guidance (a major post-crisis instrument) will be much more difficult.

There is historical precedent for the victory of political pressure, and for the recent Swiss action. In the late 1960s, the Bundesbank had to buy dollar assets in order to stop the Deutsche mark from rising, and to preserve the integrity of its fixed exchange rate. The discussion in Germany focused on the risks to the Bundesbank’s balance sheet, as well as on the inflationary pressures that came from the currency peg. Some German conservatives at the time would have liked to buy gold, but the Bundesbank had promised the Fed that it would not put the dollar under downward pressure by selling its reserves for gold.

In 1969, Germany unilaterally revalued the Deutsche mark. But that was not enough to stop inflows of foreign currency, and the Bundesbank was obliged to continue to intervene. It continued to reduce its interest rate, but the inflows persisted. In May 1971, the German government – against the wishes of the Bundesbank – abandoned the dollar peg altogether and floated the currency.

Read more at http://www.project-syndicate.org/commentary/swiss-central-bank-stops-swiss-franc-euro-peg-by-markus-brunnermeier-and-harold-james-2015-01#27qxR4lh9oqVIFft.99

This seems basically right to me, but I would point out a key difference between the 1971 episode and last week’s debacle. In 1971, the US was mired in the Vietnam War and an unstable domestic situation; to many observers, the US seemed to be in danger of a political crisis. US inflation was running at 4% a year, and its economy, just emerging from a recession, seemed in danger of stagnating. Germany, accumulating huge reserves of dollars, correctly viewed its own inflation rate of 4% as being imported from America. Totally dependent on the US for defense against the Soviet threat, Germany was in no position to demand that the US redeem its dollar obligations in gold. Given the deep German aversion to inflation, it was indeed politically impossible for the German government not to use its only available means of reducing inflation: allowing the deutschmark to appreciate against the dollar. It is much harder to identify any economic disadvantage that Switzerland has been suffering since it adopted the euro peg in 2011 that is in any way comparable to the pain of the 4% inflation that Germany had to tolerate in 1971 as a result of its dollar peg.

Can We All Export Our Way out of Depression?

Tyler Cowen has a post chastising Keynesians for scolding Germany for advising their Euro counterparts to adopt the virtuous German example of increasing their international competitiveness so that they can increase their exports, thereby increasing GDP and employment. The Keynesian response is that increasing exports is a zero-sum game, so that, far from being a recipe for recovery, the German advice is actually a recipe for continued stagnation.

Tyler doesn’t think much of the Keynesian response.

But that Keynesian counter is a mistake, perhaps brought on by the IS-LM model and its impoverished treatment of banking and credit.

Let’s say all nations could indeed increase their gross exports, although of course the sum of net exports could not go up.  The first effect is that small- and medium-sized enterprises would be more profitable in the currently troubled economies.  They would receive more credit and the broader monetary aggregates would go up in those countries, reflating their economies.  (Price level integration is not so tight in these cases, furthermore much of the reflation could operate through q’s rather than p’s.)  It sometimes feels like the IS-LM users have a mercantilist gold standard model, where the commodity base money can only be shuffled around in zero-sum fashion and not much more can happen in a positive direction.

The problem with Tyler’s rejoinder to the Keynesian response, which, I agree, provides an incomplete picture of what is going on, is that he assumes that which he wants to prove, thereby making his job just a bit too easy. That is, Tyler just assumes that “all nations could indeed increase their gross exports.” Obviously, if all nations increase their gross exports, they will very likely all increase their total output and employment. (It is, I suppose, theoretically possible that all the additional exports could be generated by shifting output from non-tradables to tradables, but that seems an extremely unlikely scenario.) The reaction of credit markets and monetary aggregates would be very much a second-order reaction. It’s the initial assumption–  that all nations could increase gross exports simultaneously — that is doing all the heavy lifting.

Concerning Tyler’s characterization of the IS-LM model as a mercantilist gold-standard model, I agree that IS-LM has serious deficiencies, but that characterization strikes me as unfair. The simple IS-LM model is a closed economy model, with an exogenously determined price level. Such a model certainly has certain similarities to a mercantilist gold standard model, but that doesn’t mean that the two models are essentially the same. There are many ways of augmenting the IS-LM model to turn it into an open-economy model, in which case it would not necessarily resemble the a mercantilist gold-standard model.

Now I am guessing that Tyler would respond to my criticism by asking: “well, why wouldn’t all countries increase their gross exports is they all followed the German advice?”

My response to that question would be that the conclusion that everybody’s exports would increase if everybody became more efficient logically follows only in a comparative-statics framework. But, for purposes of this exercise, we are not starting from an equilibrium, and we have no assurance that, in a disequilibrium environment, the interaction of the overall macro disequilibrium with the posited increase of efficiency would produce, as the comparative-statics exercise would lead us to believe, a straightforward increase in everyone’s exports. Indeed, even the comparative-statics exercise is making an unsubstantiated assumption that the initial equilibrium is locally unique and stable.

Of course, this response might be dismissed as a mere theoretical possibility, though the likelihood that widespread adoption of export-increasing policies in the midst of an international depression, unaccompanied by monetary expansion, would lead to increased output does not seem all that high to me. So let’s think about what might happen if all countries simultaneously adopted export-increasing policies. The first point to consider is that not all countries are the same, and not all are in a position to increase their exports by as much or as quickly as others. Inevitably, some countries would increase their exports faster than others. As a result, it is also inevitable that some countries would lose export markets as other countries penetrated export markets before they did. In addition, some countries would experience declines in domestic output as domestic-import competing industries were forced by import competition to curtail output. In the absence of demand-increasing monetary policies, output and employment in some countries would very likely fall. This is the kernel of truth in the conventional IS-LM analysis that Tyler tries to dismiss. The IS-LM framework abstracts from the output-increasing tendency of export-led growth, but the comparative-statics approach abstracts from aggregate-demand effects that could easily overwhelm the comparative-statics effect.

Now, to be fair, I must acknowledge that Tyler reaches a pretty balanced conclusion:

This interpretation of the meaning of zero-sum net exports is one of the most common economic mistakes you will hear from serious economists in the blogosphere, and yet it is often presented dogmatically or dismissively in a single sentence, without much consideration of more complex or more realistic scenarios.

That is a reasonable conclusion, but I think it would be just as dogmatic, if not more so, to rely on the comparative-statics analysis that Tyler goes through in the first part of his post without consideration of more complex or more realistic scenarios.

Let me also offer a comment on Scott Sumner’s take on Tyler’s post. Scott tries to translate Tyler’s analysis into macroeconomic terms to support Tyler’s comparative-statics analysis. Scott considers three methods by which exports might be increased: 1) supply-side reforms, 2) monetary stimulus aimed at currency depreciation, and 3) increased government saving (fiscal austerity). The first two, Scott believes, lead to increased output and employment, and that the third is a wash. I agree with Scott about monetary stimulus aimed at currency depreciation, but I disagree (at least in part) about the other two.

Supply-side reforms [to increase exports] boost output under either an inflation target, or a dual mandate.  If you want to use the Keynesian model, these reforms boost the Wicksellian equilibrium interest rate, which makes NGDP grow faster, even at the zero bound.

Scott makes a fair point, but I don’t think it is necessarily true for all inflation targets. Here is how I would put it. Because supply-side reforms to increase exports could cause aggregate demand in some countries to fall, and we have very little ability to predict by how much aggregate demand could go down in some countries adversely affected by increased competition from exports by other countries, it is at least possible that worldwide aggregate demand would fall if such policies were generally adopted. You can’t tell how the Wicksellian natural rate would be affected until you’ve accounted for all the indirect feedback effects on aggregate demand. If the Wicksellian natural rate fell, an inflation target, even if met, might not prevent a slowdown in NGDP growth, and a net reduction in output and employment. To prevent a slowdown in NGDP growth would require increasing the inflation target. Of course, under a real dual mandate (as opposed to the sham dual mandate now in place at the Fed) or an NGDP target, monetary policy would have to be loosened sufficiently to prevent output and employment from falling.

As far as government saving (fiscal austerity), I’d say it’s a net wash, for monetary offset reasons.

I am not sure what Scott means about monetary offset in this context. As I have argued in several earlier posts (here, here, here and here), attempting to increase employment via currency depreciation and increased saving involves tightening monetary policy, not loosening it. So I don’t see how fiscal policy can be used to depreciate a currency at the same time that monetary policy is being loosened. At any rate, if monetary policy is being used to depreciate the currency, then I see no difference between options 2) and 3).

But my general comment is that, like Tyler, Scott seems to be exaggerating the difference between his bottom line and the one that comes out of the IS-LM model, though I am certainly not saying that IS-LM is  last word on the subject.

Responding to Scott Sumner

Scott Sumner cites this passage from my previous post about coordination failures.

I can envision a pure barter economy with incorrect price expectations in which individual plans are in a state of discoordination. Or consider a Fisherian debt-deflation economy in which debts are denominated in terms of gold and gold is appreciating. Debtors restrict consumption not because they are trying to accumulate more cash but because their debt burden is so great, any income they earn is being transferred to their creditors. In a monetary economy suffering from debt deflation, one would certainly want to use monetary policy to alleviate the debt burden, but using monetary policy to alleviate the debt burden is different from using monetary policy to eliminate an excess demand for money. Where is the excess demand for money?

Evidently, Scott doesn’t quite find my argument that coordination failures are possible, even without an excess demand for money, persuasive. So he puts the following question to me.

Why is it different from alleviating an excess demand for money?

I suppose that my response is this is: I am not sure what the question means. Does Scott mean to say that he does not accept that in my examples there really is no excess demand for money? Or does he mean that the effects of the coordination failure are no different from what they would be if there were an excess demand for money, any deflationary problem being treatable by increasing the quantity of money, thereby creating an excess supply of money. If Scott’s question is the latter, then he might be saying that the two cases are observationally equivalent, so that my distinction between a coordination failure with an excess demand for money and a coordination failure without an excess demand for money is really not a difference worth making a fuss about. The first question raises an analytical issue; the second a pragmatic issue.

Scott continues:

As far as I know the demand for money is usually defined as either M/P or the Cambridge K.  In either case, a debt crisis might raise the demand for money, and cause a recession if the supply of money is fixed.  Or the Fed could adjust the supply of money to offset the change in the demand for money, and this would prevent any change in AD, P, and NGDP.

I don’t know what Scott means when he says that the demand for money is usually defined as M/P. M/P is a number of units of currency. The demand for money is some functional relationship between desired holdings of money and a list of variables that influence those desired holdings. To say that the demand for money is defined as M/P is to assert an identity between the amount of money demanded and the amount in existence which rules out an excess demand for money by definition, so now I am really confused. The Cambridge k expresses the demand for money in terms of a desired relationship between the amount of money held and nominal income. But again, I can’t tell whether Scott is thinking of k as a functional relationship that depends on a list of variables or as a definition in which case the existence of an excess demand for money is ruled out by definition. So I am still confused.

I agree that a debt crisis could raise the demand for money, but in my example, it is entirely plausible that, on balance, the demand for money to hold went down because debtors would have to use all their resources to pay the interest owed on their debts.

I don’t disagree that the Fed could engage in a monetary policy that would alleviate the debt burden, but the problem they would be addressing would not be an excess demand for money; the problem being addressed would be the debt burden. but under a gold clause inflation wouldn’t help because creditors would be protected from inflation by the requirement that they be repaid in terms of a constant gold value.

Scott concludes:

Perhaps David sees the debt crisis working through supply-side channels—causing a recession despite no change in NGDP.  That’s possible, but it’s not at all clear to me that this is what David has in mind.

The case I had in mind may or may not be associated with a change in NGDP, but any change in NGDP was not induced by an excess demand for money; it was induced by an increase in the value of gold when debts were denominated, as they were under the gold clause, in terms of gold.

I hope that this helps.

PS I see that Nick Rowe has a new post responding to my previous post. I have not yet read it. But it is near the top of my required reading list, so I hope to have a response for him in the next day or two.

Monetarism and the Great Depression

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.

foote_81The “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:

foote_83

foote_84Thus, 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.


About Me

David Glasner
Washington, DC

I am an economist at the Federal Trade Commission. Nothing that you read on this blog necessarily reflects the views of the FTC or the individual commissioners. Although I work at the FTC as an antitrust economist, most of my research and writing has been on monetary economics and policy and the history of monetary theory. In my book Free Banking and Monetary Reform, I argued for a non-Monetarist non-Keynesian approach to monetary policy, based on a theory of a competitive supply of money. Over the years, I have become increasingly impressed by the similarities between my approach and that of R. G. Hawtrey and hope to bring Hawtrey's unduly neglected contributions to the attention of a wider audience.

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