Alvin Hansen on Monetary Policy

The more you read in the history of macroeconomics and monetary theory, the more you find that current debates are reprises of arguments from 50, 100 or 200 years ago.

I’ve just been reading Perry Mehrling’s The Money Interest and the Public Interest, which  is one of the two best books I know of on this subject. (The other is Arie Arnon’s Monetary Theory and Policy Since David Hume and Adam Smith.) About a third of the book is devoted to Alvin Hansen, and it inspired me to look up some of Hansen’s writings from the 1940s and 50s. I was especially struck by this 1955 article on monetary policy. It not only anticipates much of current discussions of monetary policy — quantitative easing, the maturity structure of public debt, the need for coordination between the fiscal and monetary policy, and more broadly, the limits of a single interest rate instrument as a tool of macroeconomic management — but mostly takes them for granted as starting points for its analysis. It’s hard not to feel that macro policy debates have regressed over the past 60 years.

The context of the argument is the Treasury-Federal Reserve Accord of 1951, following which the Fed was no longer committed to maintaining fixed rates on treasury bonds of various maturities. [1] The freeing of the Fed from the overriding responsibility of stabilizing the market for government debt, led to scholarly and political debates about the new role for monetary policy. In this article, Hansen is responding to several years of legislative debate on this question, most recently the 1954 Senate hearings which included testimony from the Treasury department, the Fed Board’s Open Market Committee, and the New York Fed.

Hansen begins by expressing relief that none of the testimony raised

the phony question whether or not the government securities market is “free.” A central bank cannot perform its functions without powerfully affecting the prices of government securities.

He then expresses what he sees as the consensus view that it is the quantity of credit that is the main object of monetary policy, as opposed to either the quantity of money (a non-issue) or the price of credit (a real but secondary issue), that is, the interest rate.

Perhaps we could all agree that (however important other issues may be) control of the credit base is the gist of monetary management. Wise management, as I see it, should ensure adequate liquidity in the usual case, and moderate monetary restraint (employed in conjunction with other more powerful measures) when needed to check inflation. No doubt others, who see no danger in rather violent fluctuations in interest rates (entailing also violent fluctuations in capital values), would put it differently. But at any rate there is agreement, I take it, that the central bank should create a generous dose of liquidity when resources are not fully employed. From this standpoint the volume of reserves is of primary importance.

Given that the interest rate is alsoan object of policy, the question becomes, which interest rate?

The question has to be raised: where should the central bank enter the market -short-term only, or all along the gamut of maturities?

I don’t believe this is a question that economists asked much in the decades before the Great Recession. In most macro models I’m familiar with, there is simply “the interest rate,” with the implicit assumption that the whole rate structure moves together so it doesn’t matter which specific rate the monetary authority targets. For Hansen, by contrast, the structure of interest rates — the term and “risk” premiums — is just as natural an object for policy as the overall level of rates. And since there is no assumption that the whole structure moves together, it makes a difference which particular rate(s) the central bank targets. What’s even more striking is that Hansen not only believes that it matters which rate the central bank targets, he is taking part in a conversation where this belief is shared on all sides.

Obviously it would make little difference what maturities were purchased or sold if any change in the volume of reserve money influenced merely the level of interest rates, leaving the internal structure of rates unaffected. … In the controversy here under discussion, the Board leans toward the view that … new impulses in the short market transmit themselves rapidly to the longer maturities. The New York Reserve Bank officials, on the contrary, lean toward the view that the lags are important. If there were no lags whatever, it would make no difference what maturities were dealt in. But of course the Board does not hold that there are no lags.

Not even the most conservative pole of the 1950s debate goes as far as today’s New Keynesian orthodoxy that monetary policy can be safely reduced to the setting of a single overnight interest rate.

The direct targeting of long rates is the essential innovation of so-called quantitative easing. [2] But to Hansen, the idea that interest rate policy should directly target long as well as short rates was obvious. More than that: As Hansen points out, the same point was made by Keynes 20 years earlier.

If the central bank limits itself to the short market, and if the lags are serious, the mere creation of large reserves may not lower the long-term rate. Keynes had this in mind when he wrote: “Perhaps a complex offer by the central bank to buy and sell at stated prices gilt-edged bonds of all maturities, in place of the single bank rate for short-term bills, is the most important practical improvement that can be made in the technique of monetary management. . . . The monetary authority often tends in practice to concentrate upon short-term debts and to leave the price of long-term debts to be influenced by belated and imperfect re- actions from the price of short-term debts.” ‘ Keynes, it should be added, wanted the central bank to deal not only in debts of all maturities, but also “to deal in debts of varying degrees of risk,” i.e., high grade private securities and perhaps state and local issues.

That’s a quote from The General Theory, with Hansen’s gloss.

Fast-forward to 2014. Today we find Benjamin Friedman — one of the smartest and most interesting orthodox economists on these issues — arguing that the one great change in central bank practices in the wake of the Great Recession is intervention in a range of securities beyond the shortest-term government debt. As far as I can tell, he has no idea that this “profound” innovation in the practice of monetary policy was already proposed by Keynes in 1936. But then, as Friedman rightly notes, “Macroeconomics is a field in which theory lags behind experience and practice, not the other way around.”

Even more interesting, the importance of the rate structure as a tool of macroeconomic policy was recognized not only by the Federal Reserve, but by the Treasury in its management of debt issues. Hansen continues:

Monetary policy can operate on two planes: (1) controlling the credit base – the volume of reserve balances- and (2) changing the interest rate structure. The Federal Reserve has now backed away from the second. The Treasury emphasized in these hearings that this is its special bailiwick. It supports, so it asserts, the System’s lead, by issuing short- terms or long-terms, as the case may be, according to whether the Federal Reserve is trying to expand or contract credit … it appears that we now have (whether by accident or design) a division of monetary management between the two agencies- a sort of informal cartel arrangement. The Federal Reserve limits itself to control of the volume of credit by operating exclusively in the short end of the market. The Treasury shifts from short-term to long-term issues when monetary restraint is called for, and back to short-term issues when expansion is desired.

This is amazing. It’s not that Keynesians like Hansen  propose that Treasury should issue longer or shorter debt based on macroeconomic conditions. Rather, it is taken for granted that it does choose maturities this way. And this is the conservative side in the debate, opposed to the side that says the central bank should manage the term structure directly.

Many Slackwire readers will have recently encountered the idea that the maturities of new debt should be evaluated as a kind of monetary policy. It’s on offer as the latest evidence for the genius of Larry Summers. Proposing that Treasury should issue short or long term debt based on goals for the overall term structure of interest rates, and not just on minimizing federal borrowing costs, is the main point of Summers’ new Brookings paper, which has attracted its fair share of attention in the business press. No reader of that paper would guess that its big new idea was a commonplace of policy debates in the 1950s. [3]

Hansen goes on to raise some highly prescient concerns about the exaggerated claims being made for narrow monetary policy.

The Reserve authorities are far too eager to claim undue credit for the stability of prices which we have enjoyed since 1951. The position taken by the Board is not without danger, since Congress might well draw the conclusion that if monetary policy is indeed as powerful as indicated, nonmonetary measures [i.e. fiscal policy and price controls] are either unnecessary or may be drawn upon lightly.

This is indeed the conclusion that was drawn, more comprehensively than Hansen feared. The idea that setting an overnight interest rate is always sufficient to hold demand at the desired level has conquered the economics profession “as completely as the Holy Inquisition conquered Spain,” to coin a phrase. If you talk to a smart young macroeconomist today, you’ll find that the terms “aggregate demand was too low” and “the central bank set the interest rate too high” are used interchangeably. And if you ask, which interest rate?, they react the way a physicist might if you asked, the mass of which electron?

Faced with the argument that the inflation of the late 1940s, and price stability of the early 1950s, was due to bad and good interest rate policy respectively, Hansen offers an alternative view:

I am especially unhappy about the impli- cation that the price stability which we have enjoyed since February-March 1951 (and which everyone is justifiably happy about) could quite easily have been purchased for the entire postwar period (1945 to the present) had we only adopted the famous accord earlier …  The postwar cut in individual taxes and the removal of price, wage, and other controls in 1946 … did away once and for all with any really effective restraint on consumers. Under these circumstances the prevention of price inflation … [meant] restraint on investment. … Is it really credible that a drastic curtailment of investment would have been tolerated any more than the continuation of wartime taxation and controls? … In the final analysis, of course,  the then prevailing excess of demand was confronted with a limited supply of productive resources.

Inflation always comes down to this mismatch between “demand,” i.e. desired expenditure, and productive capacity.

Now we might say in response to such mismatches: Well, attempts to purchase more than we can produce will encourage increased capacity, and inflation is just a temporary transitional cost. Alternatively, we might seek to limit spending in various ways. In this second case, there is no difference of principle between an engineered rise in the interest rate, and direct controls on prices or spending. It is just a question of which particular categories of spending you want to hold down.

The point: Eighty years ago, Keynes suggested that what today is called quantitative easing should be a routine tool of monetary policy. Sixty years ago, Alvin Hansen believed that this insight had been accepted by all sides in macroeconomic debates, and that the importance of the term structure for macroeconomic activity guided the debt-issuance policies of Treasury as well as the market interventions of the Federal Reserve. Today, these seem like new discoveries. As the man says, the history of macroeconomics is mostly a great forgetting.

[1] I was surprised by how minimal the Wikipedia entry is. One of these days, I am going to start having students improve economics Wikipedia pages as a class assignment.

[2] What is “quantitative about this policy is that the Fed buys a a quantity of bonds, evidently in the hopes of forcing their price up, but does not announce an explicit target for the price. On the face of it, this is a strangely inefficient way to go about things. If the Fed announced a target for, say, 10-year Treasury bonds, it would have to buy far fewer of them — maybe none — since market expectations would do more of the work of moving the price. Why the Fed has hobbled itself in this way is a topic for another post.

[3] I am not the world’s biggest Larry Summers fan, to say the least. But I worry I’m giving him too hard a time in this case. Even if the argument of the paper is less original than its made out to be, it’s still correct, it’s still important, and it’s still missing from today’s policy debates. He and his coauthors have made a real contribution here. I also appreciate the Hansenian spirit in which Summers derides his opponents as “central bank independence freaks.”

The Call Is Coming from Inside the House

Paul Krugman wonders why no one listens to academic economists. Almost all the economists in the IGM Survey agree that the 2009 stimulus bill successfully reduced unemployment and that its benefits outweighed its costs. So why are these questions still controversial?

One answer is that economists don’t listen to themselves. More precisely, liberal economists like Krugman who want the state to take a more active role in managing the economy, continue to teach  an economic theory that has no place for activist policy.

Let me give a concrete example.

One of Krugman’s bugaboos is the persistence of claims that expansionary monetary policy must lead to higher inflation. Even after 5-plus years of ultra-loose policy with no rising inflation in sight, we keep hearing that since so “much money has been created…, there should already be considerable inflation.” (That’s from exhibit A in DeLong’s roundup of inflationphobia.) As an empirical matter, of course, Krugman is right. But where could someone have gotten this idea that an increase in the money supply must always lead to higher inflation? Perhaps from an undergraduate economics class? Very possibly — if that class used Krugman’s textbook.

Here’s what Krugman’s International Economics says about money and inflation:

A permanent increase in the money supply causes a proportional increase in the price level’s long-run value. … we should expect the data to show a clear-cut positive association between money supplies and price levels. If real-world data did not provide strong evidence that money supplies and price levels move together in the long run, the usefulness of the theory of money demand we have developed would be in severe doubt. 

… 

Sharp swings in inflation rates [are] accompanied by swings in growth rates of money supplies… On average, years with higher money growth also tend to be years with higher inflation. In addition, the data points cluster around the 45-degree line, along which money supplies and price levels increase in proportion. … the data confirm the strong long-run link between national money supplies and national price levels predicted by economic theory. 

… 

Although the price levels appear to display short-run stickiness in many countries, a change in the money supply creates immediate demand and cost pressures that eventually lead to future increases in the price level. 

… 

A permanent increase in the level of a country’s money supply ultimately results in a proportional rise in its price level but has no effect on the long-run values of the interest rate or real output. 

This last sentence is simply the claim that money is neutral in the long run, which Krugman continues to affirm on his blog. [1] The “long run” is not precisely defined here, but it is clearly not very long, since we are told that “Even year by year, there is a strong positive relation between average Latin American money supply growth and inflation.”

From the neutrality of money, a natural inference about policy is drawn:

Suppose the Fed wishes to stimulate the economy and therefore carries out an increase in the level of the U.S. money supply. … the U.S. price level is the sole variable changing in the long run along with the nominal exchange rate E$/€. … The only long-run effect of the U.S. money supply increase is to raise all dollar prices.

What is “the money supply”? In the US context, Krugman explicitly identifies it as M1, currency and checkable deposits, which (he says) is determined by the central bank. Since 2008, M1 has more than doubled in the US — an annual rate of increase of 11 percent, compared with an average of 2.5 percent over the preceding decade. Krugman’s textbook states, in  unambiguous terms, that such an acceleration of money growth will lead to a proportionate acceleration of inflation. He can hardly blame the inflation hawks for believing what he himself has taught a generation of economics students.

You might think these claims about money and inflation are unfortunate oversights, or asides from the main argument. They are not. The assumption that prices must eventually change in proportion to the central bank-determined money supply is central to the book’s four chapters on macroeconomic policy in an open economy. The entire discussion in these chapters is in terms of a version of the Dornbusch “overshooting” model. In this model, we assume that

1. Real exchange rates are fixed in the long run by purchasing power parity (PPP).
2. Interest rate differentials between countries are possible only if they are offset by expected changes in the nominal exchange rate.

Expansionary monetary policy means reducing interest rates here relative to the rest of the world. In a world of freely mobile capital, investors will hold our lower-return bonds only if they expect our nominal exchange rate to appreciate in the future. With the long-run real exchange rate pinned down by PPP, the expected future nominal exchange rate depends on expected inflation. So to determine what exchange rate today will make investors willing to holder our lower-interest bonds, we have to know how policy has changed their expectations of the future price level. Unless investors believe that changes in the money supply will translate reliably into changes in the price level, there is no way for monetary policy to operate in this model.

So  these are not throwaway lines. The more thoroughly a student understands the discussion in Krugman’s textbook, the stronger should be their belief that sustained expansionary monetary policy must be inflationary. Because if it is not, Krugman gives you no tools whatsoever to think about policy.

Let me anticipate a couple of objections:

Undergraduate textbooks don’t reflect the current state of economic theory. Sure, this is often true, for better or worse. (IS-LM has existed for decades only in the Hades of undergraduate instruction.) But it’s not much of a defense, is it? If Paul Krugman has been teaching his undergraduates economic theory that produces disastrous results when used as a guide for policy, you would think that would provoke some soul-searching on his part. But as far as I can tell, it hasn’t. But in this case I think the textbook does a good job summarizing the relevant scholarship. The textbook closely follows the model in Dornbusch’s Expectations and Exchange Rate Dynamics, which similarly depends on the assumption that the price level changes proportionately with the money supply. The Dornbusch article is among the most cited in open-economy macroeconomics and international finance, and continues to appear on international finance syllabuses in most top PhD programs.

Everything changes at the zero lower bound. Defending the textbook on the ground that it’s pre-ZLB effectively concedes that what economists were teaching before 2008 has become useless since then. (No wonder people don’t listen.) If orthodox theory as of 2007 has proved to be all wrong in the post-Lehmann world, shouldn’t that at least raise some doubts about whether it was all right pre-Lehmann? But again, that’s irrelevant here, since I am looking at the 9th Edition, published in 2011. And it does talk about the liquidity trap — not, to be sure, in the main chapters on macroeconomic policy, but in a two-page section at the end. The conclusion of that section is that while temporary increases in the money supply will be ineffective at the zero lower bond, a permanent increase will have the same effects as always: “Suppose the central bank can credibly promise to raise the money supply permanently … output will therefore expand, and the currency will depreciate.” (The accompanying diagram shows how the economy returns to full employment.) The only way such a policy might fail is if there is reason to believe that the increase in the money supply will subsequently be reversed. Just to underline the point, the further reading suggested on policy at the zero lower bound is an article by Lars Svennson that calls a permanent expansion in the money supply “the foolproof way” to escape a liquidity trap. There’s no suggestion here that the relationship between monetary policy and inflation is any less reliable at the ZLB; the only difference is that the higher inflation that must inevitably result from monetary expansion is now desirable rather than costly. This might help if Krugman were a market monetarist, and wanted to blame the whole Great Recession and slow recovery on bad policy by the Fed; but (to his credit) he isn’t and doesn’t.

Liberal Keynesian economists made a deal with the devil decades ago, when they conceded the theoretical high ground. Paul Krugman the textbook author says authoritatively that money is neutral in the long run and that a permanent increase in the money supply can only lead to inflation. Why shouldn’t people listen to him, and ignore Paul Krugman the blogger?

[1] That Krugman post also contains the following rather revealing explanation of his approach to textbook writing:

Why do AS-AD? First, you do want a quick introduction to the notion that supply shocks and demand shocks are different … and AS-AD gets you to that notion in a quick and dirty, back of the envelope way. 

Second — and this plays a surprisingly big role in my own pedagogical thinking — we do want, somewhere along the way, to get across the notion of the self-correcting economy, the notion that in the long run, we may all be dead, but that we also have a tendency to return to full employment via price flexibility. Or to put it differently, you do want somehow to make clear the notion (which even fairly Keynesian guys like me share) that money is neutral in the long run. That’s a relatively easy case to make in AS-AD; it raises all kinds of expositional problems if you replace the AD curve with a Taylor rule, which is, as I said, essentially a model of Bernanke’s mind.

This is striking for several reasons. First, Krugman wants students to believe in the “self-correcting economy,” even if this requires teaching them models that do not reflect the way professional economists think. Second, they should think that this self-correction happens through “price flexibility.” In other words, what he wants his students to look at, say, falling wages in Greece, and think that the problem must be that they have not fallen enough. That’s what “a return to full employment via price flexibility” means. Third, and most relevant for this post, this vision of self-correction-by-prices is directly linked to the idea that money is neutral in the long run — in other words, that a sustained increase in the money supply must eventually result in a proportionate increase in prices. What Krugman is saying here, in other words, is that a “surprising big” part of his thinking on pedagogy is how to inculcate the exact errors that drive him crazy in policy settings. But that’s what happens once you accept that your job as an educator is to produce ideological fables.

Where Do Interest Rates Come From?

What determines the level of interest rates? It seems like a simple question, but I don’t think economics — orthodox or heterodox — has an adequate answer.

One problem is that there are many different interest rates. So we have two questions: What determines the overall level of interest rates, and what determines the spreads between different interest rates? The latter in turn we can divide into the question of differences in rates between otherwise similar loans of different lengths (term spreads), differences in rates between otherwise similar loans denominated in different currencies, and all the remaining differences, grouped together under the possibly misleading name risk spreads.

In any case, economic theory offers various answers:

1. The orthodox answer, going back to the 18th century, is that the interest rate is a price that equates the desire to save with the desire to borrow. As reformulated in the later 19th century by Bohm-Bawerk, Cassel, etc., that means: The interest rate is the price of goods today relative to goods tomorrow. The interest rate is the price that balances the gains from deferring consumption with our willingness to do so. People generally prefer consumption today to consumption in the future, and because it will be possible to produce more in the future than today, so the interest rate is (normally) positive. This is a theory of all transactions that exchange spending in one period for spending (or income) in another, not specifically a theory of the interest rate on loans.

The Wicksell variant of this, which is today’s central-bank orthodoxy, is that there is a well-defined natural interest rate in this sense but that for some reason markets get this one price wrong.

2. An equally old idea is that the interest rate is the price of money. In Hume’s writings on money and interest, for instance, he vacillates between this and the previous story. It’s not a popular view in the economics profession but it’s well-represented in the business world and among populists and monetary reformers,. In this view, money is just another input to the production process, and the interest rate is its price. A creditor, in this view, isn’t someone deferring consumption to the future, but someone who — like a landlord — receives an income thanks to control of a necessary component of the production process. A business, let’s say, that needs to maintain a certain amount of working capital in the form of money or similarly liquid assets, may need to finance it with a loan on which it pays interest. Interest payments are in effect the rental price of money, set by supply and demand like anything else. As I say, this has never been a respectable view in economic theory, but you can find it in more empirical work, like this paper by Gabriel Chodorow-Reich, where credit is described in exactly these terms as an input to current production.

3. Keynes’ liquidity-preference story in The General Theory. Here again the interest rate is the price of money. But now instead of asking how much the marginal business borrower will pay for the use of money, we ask how much the marginal wealth owner needs to be compensated to give up the liquidity of money for a less-liquid bond. The other side of the market is given by a fixed stock of bonds; evidently we are dealing with a short enough period that the flow of new borrowing can be ignored, and the bond stock treated as exogenously fixed. With no new borrowing, the link from the interest rate is liked to the real economy because it is used to discount the expected flow of profits from new investment — not by business owners themselves, but by the stock market. It’s an oddly convoluted story.

4. A more general liquidity-preference story. Jorg Bibow, in a couple of his essential articles on the Keynesian theory of liquidity preference, suggests that many of the odd features of the theory are due to Keynes’ decision to drop the sophisticated analysis of the financial system from The Treatise on Money and replace it with an assumption of an exogenously fixed money stock. (It’s striking that banks play no role in in the General Theory.) But I’m not sure how much simpler this “simplification” actually makes the story, or whether it is even logically coherent; and in any case it’s clearly inapplicable to our modern world of bank-created credit money. In principle, it should be possible to tell a more general version of the liquidity preference story, where, instead of wealth holders balancing the income from holding a bond against the liquidity from holding “money,” you have banks balancing net income against incremental illiquidity from simultaneously extending a loan and creating a deposit. I’m afraid to say I haven’t read the Treatise, so I don’t know how much you can find that story there. In any case it doesn’t seem to have been developed systematically in later theories of endogenous money, which typically assume that the supply of credit is infinitely elastic except insofar as it’s limited by regulation.

5. The interest rate is set by the central bank. This is the orthodox story when we turn to the macro textbook. It’s also the story in most heterodox writers. From Wicksell onward, the whole discussion about interest rates in a macroeconomic context is about how the central bank can keep the interest rate at the level that keeps current expenditure at the appropriate level, and what happens if it fails to do so. It is sometimes suggested that the optimal or “natural” interest rate chosen by the central bank should be the the Walrasian intertemporal exchange rate — explicitly by Hayek, Friedman and sometimes by New Keynesians like Michael Woodford, and more cautiously by Wicksell. But the question of how the central bank sets the interest rate tends to drop out of view. Formally, Woodford has the central bank set the interest rate by giving it a monopoly on lending and borrowing. This hardly describes real economies, of course, but Woodford insists that it doesn’t matter since central banks could control the interest rate by standing ready to lend or borrow unlimited amounts at thresholds just above and below their target. The quite different procedures followed by real central banks are irrelevant. [1]

A variation of this (call it 5a) is where reserve requirements bind and the central bank sets the total quantity of bank credit or money. (In a world of bind reserve requirements, these will be equivalent.) In this case, the long rate is set by the demand for credit, given the policy-determined quantity. The interbank rate is then presumably bid up to the minimum spread banks are willing to lend at. In this setting causality runs from long rates to short rates, and short rates don’t really matter.

6. The interest rate is set by convention. This is Keynes’ other theory of the interest rate, also introduced in the General Theory but more fully developed in his 1937 article “Alternative Theories of the Rate of Interest.” The idea here is that changes in interest rates imply inverse changes in the price of outstanding bonds. So from the lenders’ point of view, the expected return on a loan includes not only the yield (as adjusted for default risk), but also the capital gain or loss that will result if interest rates change while the loan is still on their books. The longer the term of the loan, the larger these capital gains or losses will be. I’ve discussed this on the blog before and may come back to it in the future, but the essential point is that if people are very confident about the future value of long rates (or at least that they will not fall below some floor) then the current rate cannot get very far from that future expected rate, no matter what short rates are doing, because as the current long rate moves away from the expected long rate expected capital gains come to dominate the current yield. Take the extreme case of a perpetuity where market participants are sure that the rate will be 5% a year from now. Suppose the short rate is initially 5% also, and falls to 0. Then the rate on the perpetuity will fall to just under 4.8% and no lower, because at that rate the nearly 5% spread over the short rate just compensates market participants for the capital loss they expect when long rates return to their normal level. (Obviously, this is not consistent with rational expectations.) These kinds of self-stabilizing conventional expectations are the reason why, as Bibow puts it, “a liquidity trap … may arise at any level of interest.” A liquidity trap is an anti-bubble, if you like.

What do we think about these different stories?

I’m confident that the first story is wrong. There is no useful sense in which the interest rate on debt contracts — either as set by markets or as target by the central bank — is the price of goods today in terms of goods tomorrow. The attempt to understand interest rates in terms of the allocation across time of scarce means to alternative ends is a dead end. Some other intellectual baggage that should overboard with the “natural” rate of interest are the “real”rate of interest, the idea of consumption loans, and the intertemporal budget constraint.

But negative criticism of orthodoxy is too easy. The real work is to make a positive case for an alternative. I don’t see a satisfactory one here.

The second and third stories depend on the existence of “money” as a distinct asset with a measurable, exogenously fixed quantity. This might be a usable assumption in some historical contexts — or it might not — but it clearly does not describe modern financial systems. Woodford is right about that.

The fifth story is clearly right with respect short rates, or at least it was until recently. But it’s incomplete. As an empirical matter, it is true that interbank rates and similar short market rates closely follow the policy rate. The question is, why? The usual answer is that the central bank is the monopoly supplier of base money, and base money is used for settlement between banks. This may be so, but it doesn’t have to be. Plenty of financial systems have existed without central banks, and banks still managed to make payments to each other somehow. And where central banks exist, they don’t always have a monopoly on interbank settlement. During the 19th century, the primary tool of monetary policy at the Bank of England was the discount rate — the discount off of face value that the bank would pay for eligible securities (usually trade credit). But if the discount rate was too high — if the bank offered too little cash for securities — private banks would stop discounting securities at the central bank, and instead find some other bank that was willing to give them cash on more favorable terms. This was the problem of “making bank rate effective,” and it was a serious concern for 19th century central banks. If they tried to raise interest rates too high, they would “lose contact with the market” as banks simply went elsewhere for liquidity.

Obviously, this isn’t a problem today — when the Fed last raised policy rates in the mid-2000s, short market rates rose right along with it. Or more dramatically, Brazil’s central bank held nominal interest rates around 20 percent for nearly a decade, while inflation averaged around 8 percent. [2] In cases like these, the central bank evidently is able to keep short rates high by limiting the supply of reserves. But why in that case doesn’t the financial system develop private substitutes for reserves? Mervyn King blandly dismisses this question by saying that “it does not matter in principle whether the disequilibrium in the money market is an aggregate net shortage or a net surplus of funds—control of prices or quantities carries across irrespective of whether the central bank is the monopoly supplier or demander of its own liabilities.” [3] Clearly, the central bank cannot be both the monopoly supplier and the monopoly demander of reserves, at least not if it wants to have any effect on the rest of the world. The relevant question — to which King offers no answer — is why there are no private substitutes for central bank reserves. Is it simply a matter of legal restrictions on interbank settlements using any other asset? But then why has this one regulatory barrier remained impassable while banks have tunneled through so many others? Anyway, going forward the question may be moot if reserves remain abundant, as they will if the Fed does not shrink its balance sheet back to pre-crisis levels. In that case, new tools will be required to make the policy rate effective.

The sixth story is the one I’m most certain of. First, because it can be stated precisely in terms of asset market equilibrium. Second, because it is consistent with what we see historically. Long term interest rates are quite stable over very long periods. Third, it’s consistent with what market participants say: It’s easy to find bond market participants saying that some rate is “too low” and won’t continue, regardless of what the Fed might think. Last, but not least from my point of view, this view is clearly articulated by Keynes and by Post Keynesians like Bibow. But while I feel sure this is part of the story, it can’t be the whole story. First, because even if a conventional level of interest rates is self-stabilizing in the long run, there are clearly forces of supply and demand in credit markets that push long rates away from this level in the short run. This is even more true if what convention sets is less a level of interest rates, than a floor. And second, because Keynes also says clearly that conventions can change, and in particular that a central bank that holds short rates outside the range bond markets consider reasonable for long enough, will be able to change the definition of reasonable. So that brings us back to the question of how it is that central banks are able to set short rates.

I think the fundamental answer lies behind door number 4. I think there should be a way of describing interest rates as the price of liquidity, where liquidity refers to the capacity to honor one’s promises, and not just to some particular asset. In this sense, the scarce resource that interest is pricing is trust. And monetary policy then is at root indistinguishable from the lender of last resort function — both are aspects of the central bank’s role of standing in as guarantor for commitments within the financial system.  You can find elements of this view in the Keynesian literature, and in earlier writers going back to Thornton 200-plus years ago. But I haven’t seen it stated systematically in way that I find satisfactory.

UPDATE: For some reason I brought up the idea of the interest rate as the price of money without mentioning the classic statement of this view by Walter Bagehot. Bagehot uses the term “price of money” or “value of money” interchangeably with “discount rate” as synonyms for the interest rate. The discussion in chapter 5 of Lombard Street is worth quoting at length:

Many persons believe that the Bank of England has some peculiar power of fixing the value of money. They see that the Bank of England varies its minimum rate of discount from time to time, and that, more or less, all other banks follow its lead, and charge much as it charges; and they are puzzled why this should be. ‘Money,’ as economists teach, ‘is a commodity, and only a commodity;’ why then, it is asked, is its value fixed in so odd a way, and not the way in which the value of all other commodities is fixed? 

There is at bottom, however, no difficulty in the matter. The value of money is settled, like that of all other commodities, by supply and demand… A very considerable holder of an article may, for a time, vitally affect its value if he lay down the minimum price which he will take, and obstinately adhere to it. This is the way in which the value of money in Lombard Street is settled. The Bank of England used to be a predominant, and is still a most important, dealer in money. It lays down the least price at which alone it will dispose of its stock, and this, for the most part, enables other dealers to obtain that price, or something near it. … 

There is, therefore, no ground for believing, as is so common, that the value of money is settled by different causes than those which affect the value of other commodities, or that the Bank of England has any despotism in that matter. It has the power of a large holder of money, and no more. Even formerly, when its monetary powers were greater and its rivals weaker, it had no absolute control. It was simply a large corporate dealer, making bids and much influencing—though in no sense compelling—other dealers thereby. 

But though the value of money is not settled in an exceptional way, there is nevertheless a peculiarity about it, as there is about many articles. It is a commodity subject to great fluctuations of value, and those fluctuations are easily produced by a slight excess or a slight deficiency of quantity. Up to a certain point money is a necessity. If a merchant has acceptances to meet to-morrow, money he must and will find today at some price or other. And it is this urgent need of the whole body of merchants which runs up the value of money so wildly and to such a height in a great panic…. 

If money were all held by the owners of it, or by banks which did not pay an interest for it, the value of money might not fall so fast. … The possessors would be under no necessity to employ it all; they might employ part at a high rate rather than all at a low rate. But in Lombard Street money is very largely held by those who do pay an interest for it, and such persons must employ it all, or almost all, for they have much to pay out with one hand, and unless they receive much with the other they will be ruined. Such persons do not so much care what is the rate of interest at which they employ their money: they can reduce the interest they pay in proportion to that which they can make. The vital point to them is to employ it at some rate… 

The fluctuations in the value of money are therefore greater than those on the value of most other commodities. At times there is an excessive pressure to borrow it, and at times an excessive pressure to lend it, and so the price is forced up and down.

The relevant point in this context is the explicit statement that the interest, or discount, rate is set by the supply and demand for money. But there are a couple other noteworthy things. First, the concept of supply and demand is one of monopolistic competition, in which lenders are not price takers, but actively trade off markup against market share. And second, that the demand for money (i.e. credit) is highly inelastic because money is needed not only or mainly to purchase goods and services, but first and foremost to meet contractual money commitments.

[1] See Perry Mehrling’s useful review. Most of the text of Woodford’s textbook can be downloaded for free here. The introduction is nontechnical and is fascinating reading if you’re interested in this stuff.

[2] Which is sort of a problem for Noah Smith’s neo-Fisherite view.

[3] in the same speech, King observes that “During the 19th century, the Bank of England devoted considerable attention to making bank rate ‘effective’.” His implication is that central banks have always been able to control interest rates. But this is somewhat misleading, from my point of view: the Bank devoted so much attention to making its rate “effective” precisely because of the occasions when it failed to do so.

How Not to Think about Negative Rates

Last week’s big monetary-policy news was the ECB’s decision to target a negative interest rate, in the form of an 0.25 percent tax on bank reserves. This is the first time a major central bank has announced a negative policy rate, though some smaller ones (like the Bank of Sweden) have done so in the past few years.

Whether a tax on reserves is really equivalent to a negative interest rate, and whether this change should be expected to pass through to interest rates or credit availability for private borrowers, are not easy questions. I’m not going to try to answer them now. I just want to call attention to this rather extraordinary Neil Irwin column, as an example of how unsuited mainstream discussion is to addressing these questions.  
Here’s Irwin’s explanation of what a negative interest rate means:

When a bank pays a 1 percent interest rate, it’s clear what happens: If you deposit your money at the bank, it will pay you a penny each year for every dollar you deposited. When the interest rate is negative, the money goes the other direction. … Put bluntly: Normally the banks pay you to keep your money there. Under negative rates, you pay them for the privilege.

Not mentioned here, or anywhere else in the article, is that people pay interest to banks, as well as receiving interest from them. In Irwin’s world, “you” are always a creditor, never a borrower. 
Irwin continues:

The theory is that when it becomes more costly for European banks to keep money in the E.C.B., they will have incentive to do something else with it: Lend it out to consumers or businesses, for example.

Here’s the loanable funds theory in all its stupid glory. People put their “money” into a bank, which then either holds it or lends it out. Evidently it is not a requirement to be a finance columnist for the New York Times to know anything about how bank loans actually work. 
Irwin:

Banks will most likely pass these negative interest rates on to consumers, or at least try to. They may try to do so not by explicitly charging a negative interest rate, but by paying no interest and charging a fee for account maintenance.

Note that “consumers” here means depositors. The fact that banks also make loans has escaped Irwin’s attention entirely. 
Of course, most of us are already in this situation: We don’t receive any interest rate on our transaction balances, and pay are willing to pay various charges and fees for the liquidity benefits of holding them. 
The danger of negative rates, per Irwin, is that 

It is possible that, assuming banks pass along the negative rates through either fees or explicitly charging negative interest, people will withdraw their money as cash rather than keeping it on deposit at banks. … That is one big reason that the E.C.B. and other central banks are going to be reluctant to make rates highly negative; it could result in people pulling cash out of the banking system.

Again the quantity theory in its most naive and stupid form: there is a fixed quantity of “money” out there, which is either being kept in banks — which function, in Irwin’s world, as glorified safe deposit boxes — or under mattresses. Evidently he’s never thought about why the majority of us who already face negative rates on our checking accounts continue to hold them. More fundamentally, there’s no explanation of what makes negative rates special. Bank deposits don’t, in general, finance holdings of reserves, they finance bank loans. Any kind of expansionary policy must reduce the yield on bank loans and also — if margins are constant — on deposits and other bank liabilities. Making returns to creditors the acid test of policy, as Irwin does, would seem to be an argument against expansionary monetary policy in general — which of course it is.
What’s amazing to me in this piece is that here we have an article about monetary policy that literally makes no mention of loans or borrowers. In Irwin’s world, “you” are, by definition, an owner of financial assets; no other entities exist. It’s the 180-proof distillation of the bondholder’s view of the world.
Heterodox criticism of the loanable-funds theory of interest and insistence that loans create deposits, can sometimes come across as theological, almost ritual.  Articles like this are a reminder of why we can’t let these issues slide, if we want to make any sense of the financial universe in which we live.