New-Old Paper on the Balance of Payments

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

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

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

You can read the whole thing here.

A Quick Point on Models

According to Keynes the purpose of economics is "to provide ourselves with an organised and orderly method of thinking out particular problems"; it is "a way of thinking ... in terms of models joined to the art of choosing models which are relevant to the contemporary world." (Quoted here.)

I want to amplify on that just a bit. The test of a good model is not whether it corresponds to the true underlying structure of the world, but whether it usefully captures some of the regularities in the concrete phenomena we observe. There are lots of different regularities, more or less bounded in time, space and other dimensions, so we are going to need lots of different models, depending on the questions we are asking and the setting we are asking them in. Thus the need for the "art of choosing".

I don't think this point is controversial in the abstract. But people often lose sight of it. Obvious case: Piketty and "capital". A lot of the debate between Piketty and his critics on the left has focused on whether there really is, in some sense, a physical quantity of capital, or not. I don't think we need to have this argument.

We observe "capital" as a set of money claims, whose aggregate value varies in relation to other observable monetary aggregates (like income) over time and across space. There is a component of that variation that corresponds to the behavior of a physical stock -- increasing based on identifiable inflows (investment) and decreasing based on identifiable outflows (depreciation). Insofar as we are interested in that component of the observed variation, we can describe it using models of capital as a physical stock. The remaining components (the "residual" from the point of view of a model of physical K) will require a different set of models or stories. So the question is not, is there such a thing as a physical capital stock? It's not even, is it in general useful to think about capital as a physical stock? The question is, how much of the particular variation we are interested is accounted for by the component corresponding to the evolution of a physical stock? And the answer will depend on which variation we are interested in.

For example, Piketty could say "It's true that my model, which treats K as a physical stock, does not explain much of the historical variation in capital-output ratios at decadal frequencies, like the fall and rise over the course of the 20th century. But I believe it does explain very long-frequency variation, and in particular captures important long-run possibilities for the future." (I think he has in fact said something like this, though I can't find the quote at the moment.) You don't have to agree with him -- you could dispute that his model is a good fit for even the longest-frequency historical variation, or you could argue that the shorter frequency variation is more interesting (and is what his book often seems to be about). But it would be pointless to criticize him on the grounds that there isn't "really" such a thing as a physical capital stock, or that there is no consistent way in principle to measure it. That, to me, would show a basic misunderstanding of what models are.

An example of good scientific practice along these lines is biologists' habit of giving genes names for what happens when gross mutations are induced in them experimentally. Names like eyeless or shaggy or buttonhead: the fly lacks eyes, grows extra hair, or has a head without segments if the gene is removed. It might seem weird to describe genes in terms of what goes wrong when they are removed, as opposed to what they do normally, but I think this practice shows good judgement about what we do and don't know. In particular, it avoids any claim about what the gene is "for." There are many many relationships between a given locus in the genome and the phenotype, and no sense in which any of them is more or less important in an absolute sense. Calling it the "eye gene" would obscure that, make it sound like this is the relationship that exists out in the world, when for all we know the variation in eye development in wild populations is driven by variation in entirely other locuses. Calling it eyeless makes it clear that it's referring to what you observe in a particular experimental context.


EDIT: I hate discussions of methodology. I should not have written this post. (I only did because I liked the gene-naming analogy.)  That said, if you, unlike me, enjoy this sort of thing, Tom Hickey wrote a long and thoughtful response to it. He mentions among others, Tony Lawson, who I would certainly want to read more of if I were going to write about this stuff.

Minsky on the Non-Neutrality of Money

I try not to spend too much time criticizing orthodox economics. I think that heterodox people who spend all their energy pointing out the shortcomings and contradictions of the mainstream are, in a sense, making the same mistake as the ones who spend all their energy trying to make their ideas acceptable to the mainstream. We should focus on building up our positive knowledge of social reality, and let the profession fend for itself.

That said, like almost everyone in the world of heterodoxy I do end up writing a lot, and often obstreperously, about what is wrong with the economics profession. To which you can fairly respond: OK, but where is the alternative economics you're proposing instead?

The honest answer is, it doesn't exist. There are many heterodox economics, including a large contingent of Post Keynesians, but Post Keynesianism is not a coherent alternative research program. [1] Still, there are lots of promising pieces, which might someday be assembled into a coherent program. One of these is labeled "Minsky". [2] Unfortunately, while Minsky is certainly known to a broader audience than most economists associated with heterodoxy, it's mainly only for the financial fragility hypothesis, which I would argue is not central to his contribution.

I recently read a short piece he wrote in 1993, towards the end of his career, that gives an excellent overview of his approach. It's what I'd recommend -- along with the overview of his work by Perry Mehrling that I mentioned in the earlier post, and also the overview by Pollin and Dymski -- as a starting point for anyone interested in his work.

* * *

"The Non-Neutrality of Money" covers the whole field of Minsky's interests and can be read as a kind of summing-up of his mature thought. So it's interesting that he gave it that title. Admittedly it partly reflects the particular context it was written in, but it also, I think, reflects how critical the neutrality or otherwise of money is in defining alternative visions of what an economy is.

Minsky starts out with a description of what he takes to be the conceptual framework of orthodox economics, represented here by Ben Bernanke's "Credit in the Macroeconomy":

The dominant paradigm is an equilibrium construct in which initial endowments of agents, preference systems and production relations, along with maximizing behavior, determine relative prices, outputs and allocation... Money and financial interrelations are not relevant to the determination of these equilibrium values ... "real" factors determine "real" variables.

Some people take this construct literally. This leads to Real Business Cycles and claims that monetary policy has never had any effects. Minsky sees no point in even criticizing that approach. The alternative, which he does criticize, is to postulate some additional "frictions" that prevent the long-run equilibrium from being realized, at least right away. Often, as in the Bernanke piece, the frictions take the form of information asymmetries that prevent some mutually beneficial transactions -- loans to borrowers without collateral, say -- from taking place. But, Minsky says, there is a contradiction here.

On the one hand, perfect foresight is assumed ... to demonstrate the existence of equilibrium, and on the other hand, imperfect foresight is assumed ... to generate the existence of an underemployment equilibrium and the possibility of policy effectiveness.

Once we have admitted that money and money contracts are necessary to economic activity, and not just an arbitrary numeraire, it no longer makes sense to make simulating a world without money as the goal of policy. If money is useful, isn't it better to have more of it, and worse to have less, or none? [3] The information-asymmetry version of this problem is actually just the latest iteration of a very old puzzle that goes back to Adam Smith, or even earlier. Smith and the other Classical economists were unanimous that the best monetary system was one that guaranteed a "perfect" circulation, by which they meant, the quantity of money that would circulate if metallic currency were used exclusively. But this posed two obvious questions: First, how could you know how much metallic currency would circulate in that counterfactual world, and exactly which forms of "money" in the real world should you compare to that hypothetical amount? And second, if the ideal monetary system was one in which the quantity of money came closest to what it would be if only metal coins were used, why did people -- in the most prosperous countries especially -- go to such lengths to develop forms of payment other than metallic coins? Hume, in the 18th century, could still hew to the logic of theory and and conclude that, actually, paper money, bills of exchange, banks that functioned as anything but safety-deposit boxes [4] and all the rest of the modern financial system was a big mistake. For later writers, for obvious reasons, this wasn't a credible position, and so the problem tended to be evaded rather than addressed head on.

Or to come back to the specific way Minsky presents the problem. Suppose I have some productive project available to me but lack sufficient claim on society's resources to carry it out. In principle, I could get them by pledging a fraction of the results of my project. But that might not work, perhaps because the results are too far in the future, or too uncertain, or -- information asymmetry -- I have no way of sharing the knowledge that the project is viable or credibly committing to share its fruits. In that case "welfare" will be lower than it the hypothetical perfect-information alternative, and, given some additional assumptions, we will see something that looks like unemployment. Now, perhaps the monetary authority can in some way arrange for deferred or uncertain claims to be accepted more readily. That may result in resources becoming available for my project, potentially solving the unemployment problem. But, given the assumptions that created the need for policy in the first place, there is no reason to think that the projects funded as a result of this intervention wil be exactly the same as in the perfect-information case. And there is no reason to think there are not lots of other unrealized projects whose non-undertaking happens not to show up as unemployment. [5]

Returning to Minsky: A system of markets

is not the only way that economic interrelations can be modeled. Every capitalist economy can be described in terms of interrelated balance sheets ... The entries on balance sheets can be read as payment commitments (liabilities) and expected payment receipts (assets), both denominated in a common unit.

We don't have to see an endowments of goods, tastes for consumption, and a given technology for converting the endowments to consumption goods as the atomic units of the economy. We can instead start with a set of money flows between units, and the capitalized expectations of future money flows captured on balance sheets. In the former perspective, money payments and commitments are a secondary complication that we may want to introduce for specific problems. In the latter, Minskyan perspective, exchanges of goods are just one of the various forms of money flows between economic units.

Minsky continues:

In this structure, the real and the financial dimensions of the economy are not separated. There is no "real economy" whose behavior can be studied by abstracting from financial considerations. ... In this model, money is never neutral.

The point here, again, is that real economies require people to make commitments today on the basis of expectations extending far into an uncertain future. Money and credit are tools to allow these commitments to be made. The more available are money and credit, the further into the future can be deferred the results that will justify today's activity. If we can define a level of activity that we call full employment or price stability -- and I think Keynes was much too sanguine on this point -- then a good monetary authority may be able to regulate the flow of money or credit (depending on the policy instrument) to keep actual activity near that level. But there is no connection, logical or practical, between that state of the economy and a hypothetical economy without money or credit at all.

For Minsky, this fundamental point is captured in Keynes' two-price model. The price level of current output and capital assets are determined by two independent logics and vary independently. This is another way of saying that the classical dichotomy between relative prices and the overall price level, does not apply in a modern economy with a financial system and long-lived capital goods. Changes in the "supply of money," whatever that means in practice, always affect the prices of assets relative to current output.

The price level of assets is determined by the relative value that units place on income in the future and liquidity now. ...  

The price level of current output is determined by the labor costs and the markup per unit of output. ... The aggregate markup for consumption goods is determined by the ratio of the wage bill in investment goods, the government deficit... , and the international trade balance, to the wage bill in the production of consumption goods. In this construct the competition of interest is between firms for profits.

Here we see Minsky's Kaleckian side, which doesn't get talked about much. Minsky was convinced that investment always determined profits, never the other way round. Specifically, he followed Kalecki in treating the accounting identity that "the capitalists get what they spend" as causal. That is, total profits are determined as total investment spending plus consumption by capitalists (plus the government deficit and trade surplus.)

Coming back to the question at hand, the critical point is that liquidity (or "money") will affect these two prices differently. Think of it this way: If money is scarce, it will be costly to hold a large stock of it. So you will want to avoid committing yourself to fixed money payments in the future, you will prefer assets that can be easily converted into money as needed, and you will place a lower value on money income that is variable or uncertain. For all these reasons, long-lived capital goods will have a lower relative price in a liquidity-scare world than in a liquidity-abundant one. Or as Minsky puts it:

The non-neutrality of money ... is due to the difference in the way money enters into the determination of the price level of capital assets and of current output. ... the non-neutrality theorem reflects essential aspects of capitalism in that it recognizes that ... assets exist and that they not only yield income streams but can also be sold or pledged.

Finally, we get to Minsky's famous threefold classification of financial positions as hedge, speculative or Ponzi. In context, it's clear that this was a secondary not a central concern. Minsky was not interested in finance for its own sake, but rather in understanding modern capitalist economies through the lens of finance. And it was certainly not Minsky's intention for these terms to imply a judgement about more and less responsible financing practices. As he writes, "speculative" financing does not necessarily involve anything we would normally call speculation:

Speculative financing covers all financing that involves refinancing at market terms ... Banks are always involved in speculative financing. The floating debt of companies and governments are speculative financing.

As for Ponzi finance, he admits this memorable label was a bad choice:

I would have been better served if I had labeled the situation "the capitalization of interest." ... Note that construction finance is almost always a prearranged Ponzi financing scheme. [6]

For me, the fundamental points here are (1) That our overarching vision of capitalist economies needs to be a system of "units" (including firms, governments, etc.) linked by current money payments and commitments to future money payments, not a set of agents exchanging goods; and (2) that the critical influence of liquidity comes in the terms on which long-lived commitments to particular forms of production trade off against current income.





[1] Marxism does, arguably, offer a coherent alternative -- the only one at this point, I think. Anwar Shaikh recently wrote a nice piece, which I can't locate at the moment, contrasting the Marxist-classical and Post Keynesian  strands of heterodoxy.

[2] In fact, as Perry Mehrling demonstrates in The Money Interest and the Public Interest, Minsky represents an older and largely forgotten tradition of American monetary economics, which owes relatively little to Keynes.

[3] Walras, Wicksell and many others dismiss the idea that more money can be beneficial by focusing on its function as a unit of account. You can't consistently arrive earlier, they point out, by adjusting your watch, even if you might trick yourself the first few times. You can't get taller by redefining the inch. Etc. But this overlooks the fact that people do actually hold money, and pay real costs to acquire  it.

[4] "The dearness of every thing, from plenty of money, is a disadvantage ... This has made me entertain a doubt concerning the benefit of banks and paper-credit, which are so generally esteemed advantageous ... to endeavour artificially to encrease such a credit, can never be the interest of any trading nation; but must lay them under disadvantages, by encreasing money beyond its natural proportion to labour and commodities... And in this view, it must be allowed, that no bank could be more advantageous, than such a one as locked up all the money it received, and never augmented the circulating coin, as is usual, by returning part of its treasure into commerce." Political Discourses, 1752.

[5] This leads into Verdoorn's law and anti-hysteresis, a topic I hope to return to.

[6] Daniel Davies should appreciate this.

What to Read on Liquidity

In comments, someone asks for references behind "the point is liquidity, the point is liquidity, the point is liquidity." So, here are my recommended readings on liquidity.


Mike Beggs: "Liquidity as a Social Relation." This is the best single discussion I know of the Keynesian view of liquidity. Beside laying out the fundamental conceptual issues, and sketching the historical development of the concept, this piece also has a good discussion of how the definition of liquidity used in monetary policy has been transformed over the past couple decades. This is the first thing I'd recommend to anyone who wants to understand what exactly those of us in the left-Keynsian tradition mean by "liquidity."


John Hicks: "Liquidity." A lucid and intelligent summary of where the discussion of liquidity stood 20 years after Keynes' death.


Jorg Bibow: “Liquidity preference theory revisited: to ditch or to build on it?” A rigorous analysis of the role of liquidity in the Keynesian theory of interest rates, with particular attention to the dynamics of conventional expectations. If you want to know how Keynes' ideas about liquidity fit into contemporary debates about monetary policy, Bibow is your man. Also worth reading: "On Keynesian Theories of Liquidity Preference," and Bibow's book.


J. M. Keynes: chapters 12, 13, 15, 17 and 23 of the General Theory. Also: "The General Theory of Employment"; "The Ex-Ante Theory of Interest." The original source. I think  the presentation in the articles is clearer than in the book. Beggs and Hicks and Bibow are even clearer.


Jean Tirole, "Illiquidity and All Its Friends." Within the mainstream, Tirole has by far the best discussion of liquidity that I'm aware of. I have profoundly mixed feelings about his approach but I've certainly learned from him -- for example, the distinction between funding liquidity and market liquidity is genuinely useful. If you're tempted to criticize "mainstream" economics' treatment of liquidity, you need to seriously engage with Tirole first -- he incorporates a surprisingly large part of the Keynesian vision of liquidity into an orthodox framework.


Jim Crotty, "The Centrality of Money, Credit and Intermediation in Marx's Crisis Theory". Addresses liquidity in a somewhat different context than most of the above -- he asks how the specifically monetary character of capitalist production shapes the dynamics of accumulation as described by Marx and his followers. It's a bit askew to the other pieces here, but the underlying questions are, I think, the same. And it is one of the most brilliant scholarly essays I have read.


Perry Mehrling, "The Vision of Hyman Minsky." I think this lays out the logic of Minsky's work better than anything by Minsky himself. Also see Mehrling's book, The Money Interest and the Public Interest. Everything we need to know about liquidity is in there, though you may have to read between the lines to find it. His "Inherent Hierarchy of Money" is also useful, making the point that any system of payments is inherently hierarchical, with the same instrument appearing as credit at one level and as money at the level below.


EDIT: Should also include Joan Robinson, "The Rate of Interest," which has a useful taxonomy distinguishing illiquidity in the strict sense from capital uncertainty, income uncertainty and lender's risk.


By the way, the phrasing the post starts with is taken from Tree of Smoke, Denis Johnson's Vietnam war novel. (I know that's not what you were asking.) It's the best novel I read this year, I recommend it almost unreservedly. There of course the point is Vietnam.

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."

Varieties of Keynesianism

Here’s something interesting from Axel Leijonhufvud. It’s a response to Luigi Pasinetti’s book on Keynes, but really it’s an assessment of the Keynesian revolution in general.

There really was a revolution, according to Pasinetti, and it can be dated precisely, to 1932. Leijonhufvud:

By the Spring of that year, Keynes had concluded that the Treatise could not be salvaged by a revised edition. He still gave his “Pure Theory of Money” lecture series which was largely based on it but members of his ‘Circus’ attended and gave him trouble. The summer of that year appears to have been a critical period. In the Fall, Keynes announced a new series of lectures with the title “The Monetary Theory of Production”. The new title signaled a break with his previous work and a break with tradition. From this point onward, Keynes felt himself to be doing work that was revolutionary in nature. 

What was revolutionary about these lectures was that they weren’t about extending or modifying the established framework of economics, but about adopting a new starting point. A paradigm in economics can be thought of as defined by the minimal model — the model that (in Pasinetti’s words) “contains those analytical features, and only those features, which the theory cannot do without.” Or as I’ve suggested here, the minimal model is the benchmark of simplicity in terms of which Occam’s razor is applied.

For the orthodox economics of Keynes’s day (and ours), the minimal model was one of “real exchange” in which a given endowment of goods and a given set of preferences yielded a vector of relative prices. Money, production, time, etc. can then be introduced as extensions of this minimal model. In Keynes’ “monetary production” model, on the other hand, the “analytical features which the theory cannot do without” are a set of income flows generated in production, and a set of expenditure flows out of income. The minimal model does not include any prices or quantities. Nor does it necessarily include exchange — it’s natural to think of the income flows as consisting of profits and wages and the expenditure flows as consumption and investment, but they can just as naturally include taxes, interest payments, asset sales, and so on.

I don’t want to suggest that the monetary production paradigm has ever been as well-defined as the real exchange paradigm. One of Leijonhufvud’s main points is that there has never been a consensus on the content of the Keynesian revolution. There are many smart people who will tell you what “Keynes really meant.” With due respect (and I mean it) I’m not convinced by any of them. I don’t think anyone knows what Keynes really meant —including Keynes himself. The truth is, the Hicks-Patinkin-Samuelson version of Keynes is no bastard; its legitimate paternity is amply documented in the General Theory. Pasinetti quotes Joan Robinson: “There were moments when we had some trouble in getting Maynard to see what the point of his revolution really was.” Which doesn’t, of course, means that Hicks-Patinkin-Samuelson is the only legitimate Keynes — here even more than  in most questions of theory, we have to tolerate ambiguity and cultivate the ability to hold more than one reading in mind at once.

One basic ambiguity is in that term, “monetary production.” Which of those words is the important one?

For Pasinetti, the critical divide is between Keynes’ theory of production and the orthodox theory of exchange. Pasinetti’s production-based Keynesianism

starts from the technological imperatives stemming from the division and specialization of labor. In this context, exchange is derivative, stemming from specialization in production. How it is institutionalized and organized is a matter that the minimal production paradigm leaves open (whereas the exchange paradigm necessarily starts by assuming at least private property and often also organized markets). Prices in the production paradigm are indices of technologically determined resource costs and, as such, leave open the question whether the system does or does not have a tendency towards the full utilization of scarce resources and, in particular, of labor. …

The exchange paradigm relies on individual self-interest, on consumer’s sovereignty, and on markets and private property as the principal institutions needed to bring about a socially desirable and harmonious outcome. In putting the division of labor and specialization at center stage, the pure production model, in contrast, highlights the “necessarily cooperative aspects of any organized society…

To an unsympathetic audience, I admit, this could come across as a bunch of commencement-speech pieties. For a rigorous statement of the pure production paradigm we need to turn to Sraffa. In Production of Commodities by Means of Commodities he starts from the pure engineering facts — the input-output matrices governing production at current levels using current technology. There’s nothing about prices, demand, distribution. His system “does not explain anything about the allocation of resources. Instead, the focus is altogether on finding a logical basis for objective measurement. It is a system for coherent, internally coherent macroeconomic accounting.”

In other words: We cannot reduce the heterogeneous material of productive activity to a single objective quantity of need-satisfaction. There is no such thing. Mengers, Jevons, Walras and their successors set off after the will-o-the-wisp of utility and, to coin a phrase, vanished into a swamp, never to be heard from by positive social science again.

The question then is, how can we consistently describe economic activity using only objective, observable data? (This was also the classical question.) Sraffa answers in terms of a “snapshot” of production at a given moment. Or as Sen puts it, in a perceptive essay, he is showing how one can do economics without the use of counterfactuals.

For Pasinetti, Keynes’ revolution and Sraffa’s anti-subjectivist revival of classical economics — his effort to ground economics in engineering data — were part of the same project, of throwing out subjectivism in favor of engineering. Leijonhufvud is not convinced. “Keynes was above all a monetary economist," he notes, "and there are good reasons to believe” that it was monetary and not production that was the key term in the “theory of monetary production.” Keynes made no use of the theory of imperfect competition, despite its development by members of his inner circle (Richard Kahn and Joan Robinson). Or consider his famous reversal on wages — in the General Theory, he assumed they were equal to the marginal product of labor, which declined with the level of output. But after this claim was challenged Dunlop, Tarshis and others, he admitted there was no real evidence for it and good reason to think it was not true. [1] The fact that JMK didn’t think anything important in his theory hinged on how wages were set, at least suggests that production side of economy was not central to his project.

The important point for us is that there is one strand of Cambridge that rejects orthodoxy on the grounds that it misrepresents a system of production based on objective relationships between inputs and outputs, as a system of exchange based on subjective preferences. But this is not the only vantage point from which one can criticize the Walrasian system and it’s not clear it’s the one occupied by Keynes or by Keynesianism — whatever that may be.

The alternative standpoint is still monetary production, but with the stress on the first word rather than the second. Leijonhufvud doesn’t talk much about this here, since this is an essay about Pasinetti. But it’s evidently something along the lines of Mehrling’s “money view” or “finance view.” [2] It seems to me this view has three overlapping elements: 1. The atomic units of the economy are money flows (and commitments to future money flows), as opposed to prices and quantities. 2. Quantities are quantities of money; productive activity is not measurable except insofar as it involves money payments. 3. The active agents of the economy are seeking to maximize money income or wealth, not to end up with some preferred consumption basket. Beside Mehrling, I would include Minsky, Paul Davidson and Wynne Godley here, among others.

I’m not going to try to summarize this work here. Let me just say how I’m coming at this.

As I wrote in comments to an earlier post, what I want is to think more systematically about the relationship between the network of financial assets and liabilities recorded on balance sheets, on the one hand, and the concrete social activities of production and consumption, on the other. What we have now, it seems to me, is either a “real” view that collapses these two domains into one, with changes in ownership and debt commitments treated as if they were decisions about production and consumption; or else a “finance” view that treats balance-sheet transactions as a closed system. I think the finance view is more correct, in the sense that at least it sees half of the problem clearly. The "real" view is a hopeless muddle because it tries to treat the concrete social activity of production and consumption as if it were a set of fungible quantities like money, and to treat money commitments as if they were decisions about production and consumption. The strength of the finance view is that it recognizes the system of contingent money payments recorded on balance sheets as a distinct social activity, and not simply a reflection of the allocation of goods and services. To be clear: The purpose of recognizing finance as a distinct thing isn’t to study it in isolation, but rather to explore the specific ways in which it interacts with other kinds of social activity. This is the agenda that Fisher dynamics, disgorge the cash, functional finance and the other projects I’m working on are intended to contribute to.


[1] It’s a bit embarrassing that this “First Classical Postulate,” which Keynes himself said "is the portion of my book which most needs to be revised," is the first positive claim in the book.

[2] Mehrling prefers to trace his intellectual lineage to the independent tradition of American monetary economics of Young, Hansen and Shaw.  But I think the essential content is similar.

The Interest Rate, the Interest Rate, and Secular Stagnation

In the previous post, I argued that the term "interest rate" is used to refer to two basically unrelated prices: The exchange rate between similar goods at different periods, and the yield on a credit-market instrument. Why does this distinction matter for secular stagnation?

Because if you think the "natural rate of interest," in the sense of the credit-market rate that brings aggregate expenditure to a desired level in some real-world economic situation, should be the time-substitution rate that would exist in a model that somehow corresponds to that situation, when the two are in fact unrelated -- well then, you are going to end up with a lot of irrelevant and misleading intuitions about what that rate should be.

In general, I do think the secular stagnation conversation is a real step forward. So it's a bit frustrating, in this context, to see Krugman speculating about the "natural rate" in terms of a Samuelson-consumption loan model, without realizing that the "interest rate" in that model is the intertemporal substitution rate, and has nothing to do with the Wicksellian natural rate. This was the exact confusion introduced by Hayek, which Sraffa tore to pieces in his review, and which Keynes went to great efforts to avoid in General Theory. It would be one thing if Krugman said, "OK, in this case Hayek was right and Keynes was wrong." But in fact, I am sure, he has no idea that he is just reinventing the anti-Keynesian position in the debates of 75 years ago.

The Wicksellian natural rate is the credit-market rate that, in current conditions, would bring aggregate expenditure to the level desired by whoever is setting monetary policy. Whether or not there is a level of expenditure that we can reliably associate with "full employment" or "potential output" is a question for another day. The important point for now is "in current conditions." The level of interest-sensitive expenditure that will bring GDP to the level desired by policymakers depends on everything else that affects desired expenditure -- the government fiscal position, the distribution of income, trade propensities -- and, importantly, the current level of income itself. Once the positive feedback between income and expenditure has been allowed to take hold, it will take a larger change in the interest rate to return the economy to its former position than it would have taken to keep it there in the first place.

There's no harm in the term "natural rate of interest" if you understand it to mean "the credit market interest rate that policymakers should target to get the economy to the state they think it should be in, from the state it in now."And in fact, that is how working central bankers do understand it. But if you understand "natural rate" to refer to some fundamental parameter of the economy, you will end up hopelessly confused. It is nonsense to say that "We need more government spending because the natural rate is low," or "we have high unemployment because the natural rate is low." If G were bigger, or if unemployment weren't high, there would be a different natural rate. But when you don't distinguish between the credit-market rate and time-substitution rate, this confusion is unavoidable.

Keynes understood clearly that it makes no sense to speak of the "natural rate of interest" as a fundamental characteristic of an economy, independent of the current state of aggregate demand:

In my Treatise on Money I defined what purported to be a unique rate of interest, which I called the natural rate of interest — namely, the rate of interest which, in the terminology of my Treatise, preserved equality between the rate of saving (as there defined) and the rate of investment. I believed this to be a development and clarification of Wicksell’s “natural rate of interest”, which was, according to him, the rate which would preserve the stability if some, not quite clearly specified, price-level. 

I had, however, overlooked the fact that in any given society there is, on this definition, a different natural rate of interest for each hypothetical level of employment. And, similarly, for every rate of interest there is a level of employment for which that rate is the “natural” rate, in the sense that the system will be in equilibrium with that rate of interest and that level of employment. Thus it was a mistake to speak of the natural rate of interest or to suggest that the above definition would yield a unique value for the rate of interest irrespective of the level of employment. I had not then understood that, in certain conditions, the system could be in equilibrium with less than full employment. 

I am now no longer of the opinion that the concept of a “natural” rate of interest, which previously seemed to me a most promising idea, has anything very useful or significant to contribute to our analysis. It is merely the rate of interest which will preserve the status quo; and, in general, we have no predominant interest in the status quo as such.

EDIT: In response to Nick Edmonds in comments, I've tried to restate the argument of these posts in simpler and hopefully clearer terms:

Step 1 is to recognize that in a model like Samuelson's, "interest rate" just means any contract that allows you to make a payment today and receive a flow of income in the future. It would be the exact same model, capturing the exact same features of the economy, if we wrote "profit rate" or "house price-to-rent ratio" instead of "interest rate." Any valid intuition the model gives us, applies to ALL asset yields, not just to the the credit-instrument yields that we call "interest rates" in every day life.

Step 2 is to think about the other factors that enter into real-world asset yields, besides the intertemporal exchange rate Samuelson is interested in -- risk, liquidity, carrying costs and depreciation, and expected capital gains. Since all real-world asset yields incorporate at least one of these factors, none correspond exactly to Samuelson's intertemporal interest rate.

Step 3 is to realize that not only are credit-instrument yields not exactly the Samuelson "interest rate," they aren't even approximately it. The great majority of credit market transactions we see in real economies are not exchanges of present income for future income, but exchanges of two different claims on future income. So the intertemporal interest rate enters on both sides and cancels out.

At that point, we have established that the "interest rate" the monetary authority is targeting is not the "interest rate" Samuelson is writing about.

Step 4 is then to ask, what does it mean to say that some particular credit-market interest rate is the "natural" one? That is where the dependence on fiscal policy, income distribution, etc. come in. But those factors are not part of the argument for why the credit-market rate is not even approximately the intertemporal rate.

The Interest Rate and the Interest Rate

We will return to secular stagnation. But we need to clear some ground first. What is an interest rate?

Imagine you are in a position to acquire a claim on a series of payments  in the future. Since an asset is just anything that promises a stream of payments in the future, we will say you are thinking of buying of an asset. What will you look at to make your decision?

First is the size of the payments you will receive, as a fraction of what you pay today. We will call that the yield of the asset, or y. Against that we have to set the risk that the payments may be different from expected or not occur at all; we will call the amount you reduce your expected yield to account for this risk r. If you have to make regular payments beyond the purchase of the asset to receive income from it (perhaps taxes, or the costs of operating the asset if it is a capital good) then we also must subtract these carrying costs c. In addition, the asset may lose value over time, in which case we have to subtract the depreciation rate d. (In the case of an asset that only lasts one period -- a loan to be paid back in full the next period, say -- d will be equal to one.) On the other hand, owning an asset can have benefits beyond the yield. In particular, an asset can be sold or used as collateral. If this is easy to do, ownership of the asset allows you to make payments now, without having to waiting for its yield in the future. We call the value of the asset for making unexpected payments its liquidity premium, l. The market value of long-lasting assets may also change over time; assuming resale is possible, these market value changes will produce a capital gain g (positive or negative), which must be added to the return. Finally, you may place a lower value on the payments from the asset simply because they take place in the future; this might be because your needs now are more urgent than you expect them to be then, or simply because you prefer income in the present to income in the future. Either way, we have to subtract this pure time-substitution rate i.

So the value of an asset costing one unit (of whatever numeraire) will be 1 + y - r - c - d + l + g - i. In equilibrium, you should be just indifferent between purchasing and not purchasing this asset, so we can write:

1 + y - r - c - d + l + g - i = 1, or

(1) y = r + c + d - l - g + i

So far, there is nothing controversial.

In formal economics, from Bohm-Bawerk through Cassel, Fisher and Samuelson to today's standard models, the practice is to simplify this relationship by assuming that we can safely ignore most of these terms. Risk, carrying costs and depreciation can be netted out of yields, capital gains must be zero on average, and liquidity is assumed not to matter or just ignored. So then we have:

(2) y = i

In these models, it doesn't matter if we use the term "interest rate" to mean y or to mean i, since they are always the same.

This assumption is appropriate for a world where there is only one kind of asset -- a risk-free contract that exchanges one good in the present for 1 + i goods in the future. There's nothing wrong with exploring what the value of i would be in such a world under various assumptions.

The problem arises when we carry equation (2) over to the real world and apply it to the yield of some particular asset. On the one hand, the yield of every existing asset reflects some or all of the other terms. And on the other hand, every contract that involves payments in more than one period -- which is to say, every asset -- equally incorporates i. If we are looking for the "interest rate" of economic theory in the economic world we observe around us, we could just as well pick the rent-home price ratio, or the profit rate, or the deflation rate, or the ratio of the college wage premium to tuition costs. These are just the yields of a house, of a share of the capital stock, of cash and of a college degree respectively. All of these are a ratio of expected future payments to present cost, and should reflect i to exactly the same extent as the yield of a bond does. Yet in everyday language, it is the yield of the bond that we call "interest", even though it has no closer connection to the interest rate of theory than any of these other yields do.

This point was first made, as far as I know, by Sraffa in his review of Hayek's Prices and Production. It was developed by Keynes, and stated clearly in chapters 13 and 17 of the General Theory.

For Keynes, there is an additional problem. The price we observe as an "interest rate" in credit markets is not even the y of the bond, which would be i modified by risk, expected capital gains and liquidity. That is because bonds do not trade against baskets of goods. They trade against money. When we see a bond being sold with a particular yield, we are not observing the exchange rate between a basket of goods equivalent to the bond's value today and baskets of goods equivalent to its yield in the future. We are observing the exchange rate between the bond today and a quantity of money today. That's what actually gets exchanged. So in equilibrium the price of the bond is what equates the expected returns on the two assets:

(3) y_B - r_B + l_B + g_B - i = l_M - i

(Neither bonds nor money depreciate or have carrying costs, and money has no risk. If our numeraire is money then money also cannot experience capital gains. If our numeraire was a basket of goods instead, then we would subtract expected inflation from both sides.)

What we see is that i appears on both sides, so it cancels out. The yield of the bond is given by:

(4) y_B  = r_B - g_B + (l_M - l_B)

The yield of the bond -- the thing that in conventional usage we call the "interest rate" -- depends on the risk of the bond, the expected price change of the bond, and the liquidity premium of money compared with the bond. Holding money today, and holding a bond today, are both means to enable you to make purchases in the future. So the intertemporal substitution rate i does not affect the bond yield.

(We might ask whether the arbitrage exists that would allow us to speak of a general rate of time-substitution i in real economies at all. But for present purposes we can ignore that question and focus on the fact that even if there is such a rate, it does not show up in the yields we normally call "interest rates".)

This is the argument as Keynes makes it. It might seem decisive. But monetarists would reject it on the grounds that nobody in fact holds money as a store of value, so equation (3) does not apply. The bond-money market is not in equilibrium, because there is zero demand for money beyond that needed for current transactions at any price. (The corollary of this is the familiar monetarist claim that any change in the stock of  money must result in a proportionate change in the value of transactions, which at full employment means a proportionate rise in the price level.) From the other side, endogenous money theorists might assert that the money supply is infinitely elastic for any credit-market interest rate, so l_M is endogenous and equation (4) is underdetermined.

As criticisms of the specific form of Keynes' argument, these are valid objections. But if we take a more realistic view of credit markets, we come to the same conclusion: the yield on a credit instrument (call this the "credit interest rate") has no relationship to the intertemporal substitution rate of theory (call this the "intertemporal interest rate.")

Suppose you are buying a house, which you will pay for by taking out a mortgage equal to the value of the house. For simplicity we will assume an amortizing mortgage, so you make the same payment each period. We can also assume the value of housing services you receive from the house will also be the same each period. (In reality it might rise or fall, but an expectation that the house will get better over time is obviously not required for the transaction to take place.) So if the purchase is worth making at all, then it will result in a positive income to you in every period. There is no intertemporal substitution on your side. From the bank's point of view, extending the mortgage means simultaneously creating an asset -- their loan to you -- and a liability -- the newly created deposit you use to pay for the house. If the loan is worth making at all, then the expected payments from the mortgage exceed the expected default losses and other costs in every period. And the deposits are newly created, so no one associated with the bank has to forego any other expenditure in the present. There is no intertemporal substation on the bank's side either.

(It is worth noting that there are no net lenders or net borrowers in this scenario. Both sides have added an asset and a liability of equal value. The language of net lenders and net borrowers is carried over from models with consumption loans at the intertemporal interest rate. It is not relevant to the credit interest rate.)

If these transactions are income-positive for all periods for both sides, why aren't they carried to infinity? One reason is that the yields for the home purchaser fall as more homes are purchased. In general, you will not value the housing services from a second home, or the additional housing services of a home that costs twice as much, as much as you value the housing services of the home you are buying now. But this only tells us that for any given interest rate there is a volume of mortgages at which the market will clear. It doesn't tell us which of those mortgage volume-interest rate pairs we will actually see.

The answer is on the liquidity side. Buying a house makes you less liquid -- it means you have less flexibility if you decide you'd like to move elsewhere, or if you need to reduce your housing costs because of unexpected fall in income or rise in other expenses. You also have a higher debt-income ratio, which may make it harder for you to borrow in the future. The loan also makes the bank less liquid -- since its asset-capital ratio is now higher, there are more states of the world in which a fall in income would require it to sell assets or issue new liabilities to meet its scheduled commitments, which might be costly or, in a crisis, impossible. So the volume of mortgages rises until the excess of housing service value over debt service costs make taking out a mortgage just worth the incremental illiquidity for the marginal household, and where the excess of mortgage yield over funding costs makes issuing a new mortgage just worth the incremental illiquidity for the marginal bank.

Monetary policy affects the volume of these kinds of transactions by operating on the l terms. Normally, it does so by changing the quantity of liquid assets available to the financial system (and perhaps directly to the nonfinancial private sector as well). In this way the central bank makes banks (and perhaps households and businesses) more or less willing to accept the incremental illiquidity of a new loan contract. Monetary policy has nothing to do with substitution between expenditure in the present period and expenditure in some future period. Rather, it affects the terms of substitution between more and less liquid claims on income in the same future period.

Note that changing the quantity of liquid assets is not the only way the central bank can affect the liquidity premium. Banking regulation, lender of last resort operations and bailouts also change the liquidity premium, by chaining the subjective costs of bank balance sheet expansion. An expansion of the reserves available to the banking system makes it cheaper for banks to acquire a cushion to protect themselves against the possibility of an unexpected fall in income. This will make them more willing to hold relatively illiquid assets like mortgages. But a belief that the Fed will take emergency action prevent a bank from failing in the event of an unexpected fall in income also increases its willingness to hold assets like mortgages. And it does so by the same channel -- reducing the liquidity premium. In this sense, there is no difference in principle between monetary policy and the central bank's role as bank supervisor and lender of last resort. This is easy to understand once you think of "the interest rate" as the price of liquidity, but impossible to see when you think of "the interest rate" as the price of time substitution.

It is not only the central bank that changes the liquidity premium. If mortgages become more liquid -- for instance through the development of a regular market in securitized mortgages -- that reduces the liquidity cost of mortgage lending, exactly as looser monetary policy would.

The irrelevance of the time-substitution rate i to the credit-market interest rate y_B becomes clear when you compare observed interest rates with other prices that also should incorporate i. Courtesy of commenter rsj at Worthwhile Canadian Initiative, here's one example: the Baa bond rate vs. the land price-rent ratio for residential property.

Both of these series are the ratio of one year's payment from an asset, to the present value of all future payments. So they have an equal claim to be the "interest rate" of theory. But as we can see, none of the variation in credit-market interest rates (y_B, in my terms) show up in the price-rent ratio. Since variation in the time-substituion rate i should affect both ratios equally, this implies that none of the variation in credit-market interest rates is driven by changes in the time-substitution interest rate. The two "interest rates" have nothing to do with each other.


(Continued here.)


EDIT: Doesn't it seem strange that I first assert that mortgages do not incorporate the intertemporal interest rate, then use the house price-rent ratio as an example of a price that should incorporate that rate? One reason to do this is to test the counterfactual claim that interest rates do, after all, incorporate Samuelson's interest rate i. If i were important in both series, they should move together; if they don't, it might be important in one, or in neither.

But beyond that, I think housing purchases do have an important intertemporal component, in a way that loan contracts do not. That's because (with certain important exceptions we are all aware of) houses are not normally purchased entirely on credit. A substantial fraction of the price is paid is upfront. In effect, most house purchases are two separate transactions bundled together: A credit transaction (for, say, 80 percent of the house value) in which both parties expect positive income in all periods, at the cost of less liquid balance sheets; and a conceptually separate cash transaction (for, say, 20 percent) in which the buyer foregoes present expenditure in return for a stream of housing services in the future. Because house purchases must clear both of these markets, they incorporate i in way that loans do not. But note, i enters into house prices only to the extent that the credit-market interest rate does not. The more important the credit-market interest rate is in a given housing purchase, the less important the intertemporal interest rate is.

This is true in general, I think. Credit markets are not a means of trading off the present against the future. They are a means of avoiding tradeoffs between the present and the future.

Secular Stagnation, Progress in Economics

It's the topic of the moment. Our starting point is this Paul Krugman post, occasioned by this talk by Lawrence Summers.

There are two ways to understand "secular stagnation." One is that the growth rate of income and output will be slower in the future. The other is that there will be a systematic tendency for aggregate demand to fall short of the economy's potential output. It's the second claim that we are interested in.

For Krugman, the decisive fact about secular stagnation is that it implies a need for persistently negative interest rates. That achieved, there is no implication that growth rates or employment need to be lower in the future than in the past. He  is imagining a situation where current levels of employment and growth rates are maintained, but with permanently lower interest rates.

We could also imagine a situation where full employment was maintained by permanently higher public spending, rather than lower interest rates. Or we could imagine a situation where nothing closed the gap and output fell consistently short of potential. What matters is that aggregate expenditure by the private sector tends to fall short of the economy's potential output, by a growing margin. For reasons I will explain down the road, I think this is a better way of stating the position than a negative "natural rate" of interest.

I think this conversation is a step forward for mainstream macroeconomic thought. There are further steps still to take. In this post I describe what, for me, are the positive elements of this new conversation. In subsequent posts, I will talk about the right way of analyzing these questions more systematically -- in terms of a Harrod-type growth model -- and  about the wrong way -- in terms of the natural rate of interest.


The positive content of "secular stagnation"

1. Output is determined by demand.

The determination of total output by total expenditure is such a familiar part of the macroeconomics curriculum that we forget how subversive it is. It denies the logic of scarcity that is the basis of economic analysis and economic morality. Since Mandeville's Fable of the Bees, it's been recognized that if aggregate expenditure determines aggregate income, then, as Krugman says, "vice is virtue and virtue is vice."

A great deal of the history of macroeconomics over the past 75 years can be thought of as various efforts to expunge, exorcize or neutralize the idea of demand-determined income, or at least to safely quarantine it form the rest of economic theory. One of the most successful quarantine strategies was to recast demand constraints on aggregate output as excess demand for money, or equivalently as the wrong interest rate. What distinguished real economies from the competitive equilibrium of Jevons or Walras was the lack of a reliable aggregate demand "thermostat". But if a central bank or other authority set that one price or that one quantity correctly, economic questions could again be reduced to allocation of scarce means to alternative ends, via markets. Both Hayek and Friedman explicitly defined the "natural rate" of interest, which monetary policy should maintain, as the rate that would exist in a Walrasian barter economy. In postwar and modern New Keynesian mainstream economics, the natural rate is defined as the market interest rate that produces full employment and stable prices, without (I think) explicit reference to the intertemporal exchange rate that is called the interest rate in models of barter economies. But he equivalence is still there implicitly, and is the source of a great deal of confusion.

I will return to the question of what connection there is, if any, between the interest rates we observe in the world around us, and what a paper like Samuelson 1958 refers to as the "interest rate." The important thing for present purposes is:

Mainstream economic theory deals with the problems raised when expenditure determines output, by assuming that the monetary authority sets an interest rate such that expenditure just equals potential output. If such a policy is followed successfully, the economy behaves as if it were productive capacity that determined output. Then, specifically Keynesian problems can be ignored by everyone except the monetary-policy technicians. One of the positive things about the secular stagnation conversation, from my point of view, is that it lets Keynes back out of this box.

That said, he is only partway out. Even if it's acknowledged that setting the right interest rate does not solve the problem of aggregate demand as easily as previously believed, the problem is still framed in terms of the interest rate.


2. Demand normally falls short of potential

Another strategy to limit the subversive impact of Keynes has been to consign him to the sublunary domain of the short run, with the eternal world of long run growth still classical. (It's a notable -- and to me irritating -- feature of macroeconomics textbooks that the sections on growth seem to get longer over time, and to move to the front of the book.) But if deviations from full employment are persistent, we can't assume they cancel out and ignore them when evaluating an economy's long-run trajectory.

One of the most interesting parts of the Summers talk came when he said, "It is a central pillar of both classical models and Keynesian models, that it is all about fluctuations, fluctuations around a given mean." (He means New Keynesian models here, not what I would consider the authentic Keynes.) "So what you need to do is have less volatility." He introduces the idea of secular stagnation explicitly as an alternative to this view that demand matters only for the short run. (And he forthrightly acknowledges that Stanley Fischer, his MIT professor who he is there to praise, taught that demand is strictly a short-run phenomenon.) The real content of secular stagnation, for Summers, is not slower growth itself, but the possibility that the same factors that can cause aggregate expenditure to fall short of the economy's potential output can matter in the long run as well as in the short run.

Now for Summers and Krugman, there still exists a fundamentals-determined potential growth rate, and historically the level of activity did fluctuate around it in the past. Only in this new era of secular stagnation, do we have to consider the dynamics of an economy where aggregate demand plays a role in long-term growth. From my point of view, it's less clear that anything has changed in the behavior of the economy. "Secular stagnation" is only acknowledging what has always been true. The notion of potential output was never well defined. Labor supply and technology, the supposed fundamentals, are strongly influenced by the level of capacity utilization. As I've discussed before, once you allow for Verdoorn's Law and hysteresis, it makes no sense to talk about the economy's "potential growth rate," even in principle. I hope the conversation may be moving in that direction. Once you've acknowledged that the classical allocation-of-scarce-means-to-alternative-ends model of growth doesn't apply in present circumstances, it's easier to take the next step and abandon it entirely.


3. Bubbles are functional

One widely-noted claim in the Summers talk is that asset bubbles have been a necessary concomitant of full employment in the US since the 1980s. Before the real estate bubble there was the tech bubble, and before that there was the commercial real estate bubble we remember as the S&L crisis. Without them, the problem of secular stagnation might have posed itself much earlier.

This claim can be understood in several different, but not mutually exclusive, senses. It may be (1) interest rates sufficiently low to produce full employment, are also low enough to provoke a bubble. It may be (2) asset bubbles are an important channel by which monetary policy affects real activity. Or it may be (3) bubbles are a substitute for the required negative interest rates. I am not sure which of these claims Summers intends. All three are plausible, but it is still important to distinguish them. In particular, the first two imply that if interest rates could fall enough to restore full employment, we would have even more bubbles -- in the first case, as an unintended side effect of the low rates, in the second, as the channel through which they would work. The third claim implies that if interest rates could fall enough to restore full employment, it would be possible to do more to restrain bubbles.

An important subcase of (1) comes when there is a minimum return that owners of money capital can accept. As Keynes said (in a passage I'm fond of quoting),

The most stable, and the least easily shifted, element in our contemporary economy has been hitherto, and may prove to be in future, the minimum rate of interest acceptable to the generality of wealth-owners.[2] If a tolerable level of employment requires a rate of interest much below the average rates which ruled in the nineteenth century, it is most doubtful whether it can be achieved merely by manipulating the quantity of money.  Cf. the nineteenth-century saying, quoted by Bagehot, that “John Bull can stand many things, but he cannot stand 2 per cent.”

If this is true, then asking owners of money wealth to accept rates of 2 percent, or perhaps much less, will face political resistance. More important for our purposes, it will create an inclination to believe the sales pitch for any asset that offers an acceptable return.

Randy Wray says that Summers is carrying water here for his own reputation and his masters in Finance. The case for bubbles as necessary for full employment justifies his past support for financial deregulation, and helps make the case against any new regulation in the future. That may be true. But I still think he is onto something important. There's a long-standing criticism of market-based finance that it puts an excessive premium on liquidity and discourages investment in long-lived assets. A systematic overestimate of the returns from fixed assets might be needed to offset the systematic overestimate of the costs of illiquidity.

Another reason I like this part of Summers' talk is that it moves us toward recognizing the fundamental symmetry between between monetary policy conventionally defined, lender of last resort operations and bank regulations. These are different ways of making the balance sheets of the financial sector more or less liquid. The recent shift from talking about monetary policy setting the money stock to talking about setting interest interest rates was in a certain sense a step toward realism, since there is nothing in modern economies that corresponds to a quantity of money. But it was also a step toward greater abstraction, since it leaves it unclear what is the relationship between the central bank and the banking system that allows the central bank to set the terms of private credit transactions. Self-interested as it may be, Summers call for regulatory forbearance here is an intellectual step forward. It moves us toward thinking of what central banks do neither in terms of money, nor in terms of interest rates, but in terms of liquidity.

Finally, note that in Ben Bernanke's analysis of how monetary policy affects output, asset prices are an important channel. That is an argument for version (2) of the bubbles claim.


4. High interest rates are not coming back

For Summers and Krugman, the problem is still defined in terms of a negative "natural rate" of interest. (To my mind, this is the biggest flaw in their analysis.) So much of the practical discussion comes down to how you convince or compel wealth owners to hold assets with negative yields. One solution is to move to permanently higher inflation rates. (Krugman, to his credit, recognizes that this option will only be available when or if something else raises aggregate demand enough to push against supply constraints.) I am somewhat skeptical that capitalist enterprises in their current form can function well with significantly higher inflation. The entire complex of budget and invoicing practices assumes that over some short period -- a month, a quarter, even a year -- prices can be treated as constant. Maybe this is an easy problem to solve, but maybe not. Anyway, it would be an interesting experiment to find out!

More directly relevant is the acknowledgement that interest rates below growth rates may be a permanent feature of the economic environment for the foreseeable future. This has important implications for debt dynamics (both public and private), as we've discussed extensively on this blog. I give Krugman credit for saying that with i < g, it is impossible for debt to spiral out of control; a deficit of any level, maintained forever, will only ever cause the debt-GDP ratio to converge to some finite level. (I also give him credit for acknowledging that this is a change in his views.) This has the important practical effect of knocking another leg out from the case for austerity. It's been a source of great frustration for me to see so many liberal, "Keynesian" economists follow every argument for stimulus with a pious invocation of the need for long-term deficit reduction. If people no longer feel compelled to bow before that shrine, that is progress.

On a more abstract level, the possibility of sub-g or sub-zero interest rates helps break down the quarantining of Keynes discussed above. Mainstream economists engage in a kind of doublethink about the interest rate. In the context of short-run stabilization, it is set by the central bank. But in other contexts, it is set by time preferences and technological tradeoff between current and future goods. I don't think there was ever any coherent way to reconcile these positions. As I will explain in a following post, the term "interest rate" in these two contexts is being used to refer to two distinct and basically unrelated prices. (This was the upshot of the Sraffa-Hayek debate.) But as long as the interest rate observed in the world (call it the "finance" interest rate) behaved similarly enough to the interest rate in the models (the "time-substitution" interest rate), it was possible to ignore this contradiction without too much embarrassment.

There is no plausible way that the "time substitution" interest rate can be negative. So the secular stagnation conversation is helping reestablish the point -- made by Keynes in chapter 17 of the General Theory, but largely forgotten -- that the interest rates we observe in the world are something different. And in particular, it is no longer defensible to treat the interest rate as somehow exogenous to discussions about aggregate demand and fiscal policy. When I was debating fiscal policy with John Quiggin, he made the case for treating debt sustainability as a binding constraint by noting that there are long periods historically when interest rates were higher than growth rates. It never occurred to him that it makes no sense to talk about the level of interest rates as an objective fact, independent of the demand conditions that make expansionary fiscal policy desirable. I don't mean to pick on John -- at the time it wasn't clear to me either.

Finally, on the topic of low interest forever, I liked Krugman's scorn for the rights of interest-recipients:

How dare anyone suggest that virtuous individuals, people who are prudent and save for the future, face expropriation? How can you suggest steadily eroding their savings either through inflation or through negative interest rates? It’s tyranny!
But in a liquidity trap saving may be a personal virtue, but it’s a social vice. And in an economy facing secular stagnation, this isn’t just a temporary state of affairs, it’s the norm. Assuring people that they can get a positive rate of return on safe assets means promising them something the market doesn’t want to deliver – it’s like farm price supports, except for rentiers.

It's a nice line, only slightly spoiled by the part about "what the market wants to deliver." The idea that it is immoral to deprive the owners of money wealth of their accustomed returns is widespread and deeply rooted. I think it lies behind many seemingly positive economic claims. If this conversation develops, I expect we will see more open assertions of the moral entitlement of the rentiers.

Thomas Sargent Abandons Rational Expectations, Converts to Post Keynesianism

From Keynes (1937), "The General Theory of Employment":

We have, as a rule, only the vaguest idea of any but the most direct consequences of our acts. Sometimes we are not much concerned with their remoter consequences, even though time and chance may make much of them. But sometimes we are intensely concerned with them... The whole object of the accumulation of wealth is to produce results, or potential results, at a comparatively distant, and sometimes indefinitely distant, date. Thus the fact that our knowledge of the future is fluctuating, vague and uncertain, renders wealth a peculiarly unsuitable subject for the methods of the classical economic theory. ... 

By ‘uncertain’ knowledge, let me explain, I do not mean merely to distinguish what is known for certain from what is only probable. The game of roulette is not subject, in this sense, to uncertainty... Even the weather is only moderately uncertain. The sense in which I am using the term is that in which the prospect of an European war is uncertain, or the price of copper and the rate of interest twenty years hence, or the obsolescence of a new invention, or the position of private wealth-owners in the social system in 1970. About these matters there is no scientific basis on which to form any calculable probability whatever. We simply do not know.

Better late than never, I suppose...


UPDATE: OK, ok, Sargent has written a lot about uncertainty and expectations.  Harry Konstantidis points out this 1972 article Rational Expectations and the Term Structure of Interest Rates, which is ... really interesting, actually. It's an empirical test of whether the behavior of interest rates over time is consistent with bond prices being set by a process of rational expectations. The conclusions are surprisingly negative:

The evidence summarized above implies that it is difficult to maintain both that only expectations determine the yield curve and that expectations are rational in the sense of efficiently incorporating available information. The predictions of the random walk version of the model are fairly decisively rejected by the data, particularly for forward rates with less than five years term to maturity. ... 

It is clear that our conclusions apply with equal force to the diluted form of the expectations hypothesis that allows forward rates to be determined by expectations plus time-invariant liquidity premiums. ... On the other hand, it would clearly be possible to determine a set of time-dependent "liquidity premiums" that could be used to adjust the forward rates so that the required sequences would display "white" spectral densities. ... While this procedure has its merits in certain instances, it is essentially arbitrary, there being no adequate way to relate the "liquidity premiums" so derived to objective characteristics of markets... 

An alternative way to "save" the doctrine that expectations alone determine the yield curve in the face of empirical evidence like that presented above is to abandon the hypothesis that expectations are rational. Once that is done, the model becomes much freer, being capable of accommodating all sorts of ad hoc, plausible hypotheses about the formation of expectations. Yet salvaging the expectations theory in that way involves building a model of the term structure that ... permits expectations to be formed via a process that could utilize available information more efficiently and so enhance profits. That seems ... extremely odd.

In other words: Observed yields are inconsistent with a simple version of rational expectations. They could be made consistent, but only by trvializing the theory by adding ad hoc adjustments that could fit anything. We might conclude that expectations are not rational, but that's too scary. So ... who knows.

One unambiguous point, though, is that under rational expectations interest rates should follow a random walk, and your best prediction of interest rates on a given instrument at some future date should be the rate today. Just saying "I don't now" is not consistent with rational expectations -- for one thing, it gives you no basis for deciding whether a product like the one being advertised here is priced fairly. Sargent's "No" is consistent, though, with fundamental uncertainty in the Keynes sense. In that case the decision to buy or not buy is based on nonrational behavioral rules -- like, say, looking at endorsements of recognized authorities. (Keynes: "Knowing that our individual judgment is worthless, we endeavour to fall back on the judgment of the rest of the world which is perhaps better informed.") So I stand by my one-liner.