What is ‘effective demand’?

18 Jul, 2016 at 11:04 | Posted in Economics | 7 Comments

J__Jespersen_683346aEconomists of all shades have generally misunderstood the theoretical structure of Keynes’s The General Theory. Quite often this is a result of misunderstanding the concept of ‘effective demand’ — one of the key theoretical innovations of The General Theory.

Jesper Jespersen untangles the concept and shows how Keynes, by taking uncertainty seriously, contributed to forming an analytical alternative to the prevailing neoclassical general equilibrium framework:

Effective demand is one of the distinctive analytical concepts that Keynes developed in The General Theory. Demand and demand management have thereby come to represent one of the distinct trademarks of Keynesian macroeconomic theory and policy. It is not without reason that the central position of this concept has left the impression that Keynes’s macroeconomic model predominantly consists of theories for determining demand, while the supply side is neglected. From here it is a short step within a superficial interpretation to conclude that Keynes (and post-Keynesians) had ended up in a theoretical dead end, where macroeconomic development is exclusively determined by demand factors …

It is the behaviour of profit-seeking firms acting under the ontological condition of uncertainty that is at the centre of post-Keynesian concept of effective demand. It is entrepreneurs’ expectations with regard to demand and supply factor that determine their plans for output as a whole and by that the effective demand for labour.

Therefore, it was somewhat unfortunate that Keynes called his new analytical concept ‘effective demand’, which may have contributed to misleading generations of open minded macroeconomists to concluding that it was exclusively realized demand for consumer and investment goods that drives the macroeconomic development. Hereby a gateway for the IS/LM-model interpretation of effective demand was opened, where demand creates its own supply.

tmp10C1_thumb1On the contrary, it is the interaction between the sum of the individual firms’ sales expectations (aggregate demand) and their estimated production costs (aggregate supply) that together with a number of institutional conditions (bank credit, labour market organization, global competition and technology) determine the business sector decisions on output as a whole and employment …

The supply side in the goods market is an aggregate presentation of firms’ cost functions considered as a whole. It shows a relation between what Keynes called ‘supply price’, i.e. the sales proceeds that, given the production function and cost structures, is needed to ‘just make it worth the while of the entrepreneurs to give that employment’ (Keynes, 1936: 24). This means that behind the supply curve there is a combination of variable costs plus an expected profit at different levels of employment. At each level firms try to maximise their profit, if they succeed there is no (further) incentive for firms to change production or employment.

These assumptions entail that the aggregate supply function (what Keynes called the Z-curve) is upward sloping and represents the proceeds that has to be expected by the industry as a whole to make a certain employment ‘worth undertaken’ … In fact, this aggregate supply function looks like it was taken directly from a standard, neoclassical textbook, where decreasing marginal productivity of labour within the representative firm is assumed; the main difference is that Keynes is dealing with the aggregate sum of heterogeneous firms i.e. the industry as a whole.

The other equally important part of effective demand is aggregate demand function, which is the value of the sales that firms as a whole expect at different levels of macro-activity measured by employment (as a whole) …

Firms make a kind of survey-based expectation with regard to the most likely development in sales and proceeds in the nearer future. This expectation of aggregate demand (as a whole) is a useful point of departure for the individual firms when they have to form their specific expectation of future proceeds. This sales expectation will therefore centre around the future macroeconomic demand (and on the intensity of international competition).

Accordingly, Keynes’s macro-theory has a microeconomic foundation of firms trying to maximise profit, but differs from neoclassical theory by introducing uncertainty related to the future, which makes an explicit introduction of aggregate demand relevant i.e. the expected sales proceeds by business as a whole.

‘Effective demand’ is nothing but the value of the aggregate demand function where it equals the aggregate supply function, which is at the point where the firms expect to maximize their profits. To Keynes — contrary to the ‘classical’ theory, which assumes that aggregate demand always accommodates to aggregate supply and hence is consistent with ‘effective demand’ having an infinite range of values — ‘effective demand’ has a unique equilibrium value. And — most importantly — that value may be at a level below the one that is compatible with full employment.

The invisible hand — invisible because it’s not there

17 Jul, 2016 at 22:13 | Posted in Economics | 1 Comment

Daniel Kahneman … has demonstrated how individuals systematically behave in ways less rational than orthodox economists believe they do. His research shows not only that individuals sometimes act differently than standard economic theories predict, but that they do so regularly, systematically, and in ways that can be understood and interpreted through alternative hypotheses, competing with those utilised by orthodox economists.

stiglitz3To most market participants – and, indeed, ordinary observers – this does not seem like big news … In fact, this irrationality is no news to the economics profession either. John Maynard Keynes long ago described the stock market as based not on rational individuals struggling to uncover market fundamentals, but as a beauty contest in which the winner is the one who guesses best what the judges will say …

Adam Smith’s invisible hand – the idea that free markets lead to efficiency as if guided by unseen forces – is invisible, at least in part, because it is not there …

For more than 20 years, economists were enthralled by so-called “rational expectations” models which assumed that all participants have the same (if not perfect) information and act perfectly rationally, that markets are perfectly efficient, that unemployment never exists (except when caused by greedy unions or government minimum wages), and where there is never any credit rationing.

That such models prevailed, especially in America’s graduate schools, despite evidence to the contrary, bears testimony to a triumph of ideology over science. Unfortunately, students of these graduate programmes now act as policymakers in many countries, and are trying to implement programmes based on the ideas that have come to be called market fundamentalism … Good science recognises its limitations, but the prophets of rational expectations have usually shown no such modesty.

Joseph Stiglitz

On the limits of the invisible hand

17 Jul, 2016 at 13:43 | Posted in Economics | 5 Comments

It might look trivial at first sight, but what Harold Hotelling did show in his classic paper Stability in Competition (1929) was that there are cases when Adam Smith’s invisible hand doesn’t actually produce a social optimum.

With the advent of neoclassical economics at the end of the 19th century a large amount of intellectual energy was invested in trying to formalize the stringent conditions of obtaining equilibrium and showing in what way the prices and quantities of free competition constituted some kind of social optimum.

That the equilibrium reached in free competition is an optimum for each individual – given prevailing prices and income distribution – was not, however, seen by some economists as making a very strong case for a free market economy per se. It wasn’t possible to prove that free trade and competition gave a maximum of social utility. The gains made in exchange weren’t a manifestation of a maximum social utility.

wicksell2Knut Wicksell was one of those who criticized the idea of regarding the gain in utility arising from free competition as an absolute maximum. This market fundamentalist idea of harmony in a free market system didn’t live up to Wicksell’s demand for objectivity in science – and  “the harmony economists, who endeavoured to extend the doctrine so that it might become a defence of the existing distribution of wealth” were judged severely by Wicksell (Lectures 1934 (1901) p. 39).

When propounders of the new marginalist theory – especially Walras and Pareto – overstepped the strict boundaries of science and used it in ascribing to the market properties it did not possess, Wicksell had to react. To Wicksell (Lectures 1934 (1901) p. 73) it was

almost tragic that Walras … imagined that he had found the rigorous proof … merely because he clothed in mathematical formula the very arguments which he considered insufficient when they were expressed in ordinary language.

But what about the Pareto criterion? Wicksell had actually more or less anticipated it in his review (in Zeitschrift für Volkswirtschaft, Sozialpolitik und Verwaltung, 1913: 132-51) of Pareto’s Manuel, but didn’t think it really contributed anything useful. It was just the same old doctrine in a new disguise. To Wicksell the market fundamentalist doctrine of the Lausanne School obviously didn’t constitute an advance in economics.

From a methodological point of view there are also one or two lessons to learn from this history.

Models may help us to explain things by providing us with a frame/instrument for analysing and explaining the real world. However, to do that, there has to be an adequate similarity between model and reality. Otherwise they cannot function as eye openers that widen our cognitive horizon and make it possible to see and detect fundamental forces/ relations/mechanisms operating in the real world. And — most importantly — we always have to scrutinize the assumptions the models build on and so test their plausibility.

Logic, coherence, consistency, simplicity, and deductivity is not enough. Without confronting models with the real world, they are nothing but empty thought experiments — and should be treated as such.

David K. Levine — unlucky when trying to think

17 Jul, 2016 at 11:54 | Posted in Economics | 3 Comments

50cf9626f2deeIn the wake of the latest financial crisis many people have come to wonder why economists never have been able to predict these manias, panics and crashes that haunt our economies.

In responding to these warranted wonderings, some economists – like professor David K. Levine in the article Why Economists Are Right: Rational Expectations and the Uncertainty Principle in Economics in the Huffington Post – have maintained that

it is a fundamental principle that there can be no reliable way of predicting a crisis.

To me this is a totally inadequate answer. And even trying to make an honour out of the inability of one’s own science to give answers to just questions, is indeed proof of a rather arrogant and insulting attitude.

Fortunately yours truly is not the only one racting to this guy’s arrogance …

Steve Blough trolls me this morning over on the Twitter Machine about the truly remarkable ignorance of economics professor David K. Levine:

I confess I am embarrassed for my great-grandfather Roland Greene Usher, who sweated blood all his life trying to help build Washington University in St. Louis into a great university, that WUSTL now employs people like David K. Levine:

Levine, you see, appears to believe that we live not in a monetary but in a barter economy. And so Levine claims that the Friedmanite-monetarist expansionary policies to fight recessions that recommended by Milton Friedman cannot, in fact, work:

David K. Levine: The Keynesian Illusion:
I want to think here of a complete economy peopled by real people … a phone guy who makes phones, a burger flipper, a hairdresser and a tattoo artist…. The burger flipper only wants a phone, the hairdresser only wants a burger, the tattoo artist only wants a haircut and the phone guy only wants a tattoo…. Each can produce one phone, burger, haircut or tattoo…. The phone guy produces a phone, trades it to the tattoo artist in exchange for a tattoo, who trades the phone to the hairdresser in exchange for a haircut, who trades it to burger flipper in exchange for a burger. All are employed… everyone is happy.

Now suppose that the phone guy suddenly decides he doesn’t like tattoos enough to be bothered building a phone…. Catastrophe. Everyone is unemployed…. The stupid phone guy… is lazy and doesn’t want to work…. The burger flipper would like to work making burgers if he can get a phone, the hairdresser would like cut hair if he could get a burger and the tattoo artist would like to work if he could get a haircut and yet all are unemployed …

Maybe the government should follow Keynes’s [note: Levine means “Milton Friedman’s” here] advice and print some money…. Then the phone guy can buy a tattoo, and the tattoo guy can buy a haircut and the haircutter can buy a burger, and the burger flipper — ooops… he can’t buy a phone because there are no phones…. [Perhaps] the burger flipper realizes he shouldn’t sell the burger because he can’t buy anything he wants… and we are right back… with everyone unemployed…. Maybe he doesn’t realize that and gets left holding the bag… a Ponzi scheme…. It seems like a poor excuse for economic policy that our plan is that we hope the burger flipper will be a fool and be willing to be left holding the bag.

DKL’s argument that Friedmanite-monetarist expansionary policies cannot cure a downturn is, I believe, correct — if the downturn is caused by a sudden outbreak of worker laziness, an adverse supply shock that reduces potential output.

Expansionary monetary policy in such a situation will indeed produce inflation. People’s expectations of the prices at which they will be able to buy are disappointed on the upside as too much money chases too few goods. It is not clear to me why DKL calls this a “Ponzi scheme” rather than “unanticipated inflation”.

But does anybody — save DKL — believe that an extraordinary and contagious outbreak of worker laziness is what caused the downturn that began in 2008?


Everybody else believes that the downturn that began in 2008 occurred not because of a supply shock in which workers suddenly became lazy but because of a demand shock in which the financial crisis caused nearly everybody in the economy to try to rebuild their stocks of safe, liquid, secure financial assets. Everybody else believes that the right way to model the economy is not the barter economy of DKL — trading phones for tattoos, etc. — but as a monetary economy, in which people hold stocks of financial assets and trade them for currently-produced goods and services.

This matters.

This matters a lot.

Brad DeLong

Per Svensson — ännu en av dessa antidemokratiska demokrater

17 Jul, 2016 at 10:42 | Posted in Politics & Society | Comments Off on Per Svensson — ännu en av dessa antidemokratiska demokrater

Inför brexit-omröstningen var det få kommentatorer som ondgjorde sig över att man i Storbritannien valt att låta medborgarna i en folkomröstning tala om huruvida man ville stanna kvar i EU eller ej. För de flesta framstod detta lika självklart som att Sverige för lite mer än tio år sedan folkomröstade om vi ville vara med i EMU eller ej.

slide_3Men när väl det — för de flesta — överraskande resultatet av brexit-omröstningen stod klart blev det andra tongångar. När ‘folket’ inte valde som ‘etablissemanget’ var det helt plötsligt sååå fel med folkomröstningar.

En av alla dessa debattörer och kommentatorer som nu förfasar sig över att britterna ‘valde fel’ är Sydsvenskans Per Svensson. I en artikel med rubriken Med folkets stöd mot avgrunden talar Svensson — hedersdoktor vid Malmö högskola — om att folkomröstningar mest är något som ‘karikerar’ demokrati och utnyttjas av ‘populister’ och ‘charlataner’. Tanken att en majoritet av britterna ville lämna EU skulle kunna bero på att för de minst bemedlade och svagaste grupperna har EU och dess åtstramningspolitik inte levererat ett dyft, föresvävar uppenbarligen inte Svensson.

När resultatet inte gick etablissemangets väg är helt plötsligt folkomröstningsinstitutet inte ett uttryck för ‘verklig’ demokrati.

Får man föreslå herr Svensson en resa till Schweiz? Eller det är kanske också bara ett land där ‘eliten’ utnyttjar ‘folket’ för att driva igenom sina egna intressen?

Demokrati är ingen gottepåse.

Demokrati är inget vi står upp för bara när den resulterar i beslut som vi gillar.

Demokrati och ‘rule of law’ är något vi ska slå vakt om. Överallt. Alltid.

L’urne que nous interrogeons

15 Jul, 2016 at 19:19 | Posted in Economics | Comments Off on L’urne que nous interrogeons

treatprob-2In my judgment, the practical usefulness of those modes of inference, here termed Universal and Statistical Induction, on the validity of which the boasted knowledge of modern science depends, can only exist—and I do not now pause to inquire again whether such an argument must be circular—if the universe of phenomena does in fact present those peculiar characteristics of atomism and limited variety which appear more and more clearly as the ultimate result to which material science is tending …

The physicists of the nineteenth century have reduced matter to the collisions and arrangements of particles, between which the ultimate qualitative differences are very few …

The validity of some current modes of inference may depend on the assumption that it is to material of this kind that we are applying them … Professors of probability have been often and justly derided for arguing as if nature were an urn containing black and white balls in fixed proportions. Quetelet once declared in so many words—“l’urne que nous interrogeons, c’est la nature.” But again in the history of science the methods of astrology may prove useful to the astronomer; and it may turn out to be true—reversing Quetelet’s expression—that “La nature que nous interrogeons, c’est une urne”.

Professors of probability and statistics, yes. And more or less every mainstream economist!

On tour (personal)

14 Jul, 2016 at 09:37 | Posted in Varia | Comments Off on On tour (personal)

Touring Germany yours truly also had time to visit son completing law studies at Heidelberg University. Amazingly beautiful town.

Critical inspiration

11 Jul, 2016 at 09:28 | Posted in Economics | 4 Comments


Almost a century and a half after Léon Walras founded neoclassical general equilibrium theory, economists still have not been able to show that markets move economies to equilibria. What we do know is that — under very restrictive assumptions — unique Pareto-efficient equilibria do exist.

But what good does that do? As long as we cannot show, except under exceedingly unrealistic assumptions, that there are convincing reasons to suppose there are forces which lead economies to equilibria – the value of general equilibrium theory is nil. As long as we cannot really demonstrate that there are forces operating — under reasonable, relevant and at least mildly realistic conditions — at moving markets to equilibria, there cannot really be any sustainable reason for anyone to pay any interest or attention to this theory. A stability that can only be proved by assuming “Santa Claus” conditions is of no avail. Most people do not believe in Santa Claus anymore. And for good reasons. Santa Claus is for kids.

Continuing to model a world full of agents behaving as economists — “often wrong, but never uncertain” — and still not being able to show that the system under reasonable assumptions converges to equilibrium (or simply assume the problem away), is a gross misallocation of intellectual resources and time.

In case you think this verdict is only a heterodox idiosyncrasy, here’s what one of the world’s greatest microeconomists — Alan Kirman — writes in his thought provoking paper The intrinsic limits of modern economic theory:

If one maintains the fundamentally individualistic approach to constructing economic models no amount of attention to the walls will prevent the citadel from becoming empty …

kirman[The results of Sonnenchein (1972), Debreu (1974), Mantel (1976) and Mas Collel (1985)] shows clearly why any hope for uniqueness or stability must be unfounded …

The idea that we should start at the level of the isolated individual is one which we may well have to abandon … we should be honest from the outset and assert simply that by assumption we postulate that each sector of the economy behaves as one individual and not claim any spurious microjustification …

Economists therefore should not continue to make strong assertions about this behaviour based on so-called general equilibrium models which are, in reality, no more than special examples with no basis in economic theory as it stands.

Getting around Sonnenschein-Mantel-Debreu using representative agents may be — from a purely formalistic point of view — very expedient. But relevant and realistic? No way!

Although garmented as a representative agent, the emperor is still naked.

Axel Leijonhufvud on why economics has become so boring

11 Jul, 2016 at 00:05 | Posted in Economics | Comments Off on Axel Leijonhufvud on why economics has become so boring

51BMduFh0cL._SX373_BO1,204,203,200_Trying to delineate the difference between ‘New Keynesianism’ and ‘Post Keynesianism’ — during an interview a couple of months ago — yours truly was confronted by the odd and confused view that Axel Leijonhufvud was a ‘New Keynesian.’ I wasn’t totally surprised — I had run into that misapprehension before — but still, it’s strange how wrong people sometimes get things.

The  last time I met Axel, we were both invited keynote speakers at the conference “Keynes 125 Years – What Have We Learned?” in Copenhagen. Axel’s speech was later published as Keynes and the crisis and contains the following thought provoking passages:

For many years now, the main alternative to Real Business Cycle Theory has been a somewhat loose cluster of models given the label of New Keynesian theory. New Keynesians adhere on the whole to the same DSGE modeling technology as RBC macroeconomists but differ in the extent to which they emphasise inflexibilities of prices or other contract terms as sources of shortterm adjustment problems in the economy. The “New Keynesian” label refers back to the “rigid wages” brand of Keynesian theory of 40 or 50 years ago. Except for this stress on inflexibilities this brand of contemporary macroeconomic theory has basically nothing Keynesian about it.

The obvious objection to this kind of return to an earlier way of thinking about macroeconomic problems is that the major problems that have had to be confronted in the last twenty or so years have originated in the financial markets – and prices in those markets are anything but “inflexible”. But there is also a general theoretical problem that has been festering for decades with very little in the way of attempts to tackle it. Economists talk freely about “inflexible” or “rigid” prices all the time, despite the fact that we do not have a shred of theory that could provide criteria for judging whether a particular price is more or less flexible than appropriate to the proper functioning of the larger system. More than seventy years ago, Keynes already knew that a high degree of downward price flexibility in a recession could entirely wreck the financial system and make the situation infinitely worse. But the point of his argument has never come fully to inform the way economists think about price inflexibilities …

I began by arguing that there are three things we should learn from Keynes … The third was to ask whether events provedthat existing theory needed to be revised. On that issue, I conclude that dynamic stochastic general equilibrium theory has shown itself an intellectually bankrupt enterprise. But this does not mean that we should revert to the old Keynesian theory that preceded it (or adopt the New Keynesian theory that has tried to compete with it). What we need to learn from Keynes, instead, are these three lessons about how to view our responsibilities and how to approach our subject.

Economics has become boring? Yes. Axel Leijonhufvud a ‘New Keynesian’? Forget it!

How Richard Posner became a Keynesian

10 Jul, 2016 at 15:52 | Posted in Economics | 1 Comment

Until [2008], when the banking industry came crashing down and depression loomed for the first time in my lifetime, I had never thought to read The General Theory of Employment, Interest, and Money, despite my interest in economics … I had heard that it was a very difficult book and that the book had been refuted by Milton Friedman, though he admired Keynes’s earlier work on monetarism. I would not have been surprised by, or inclined to challenge, the claim made in 1992 by Gregory Mankiw, a prominent macroeconomist at Harvard, that “after fifty years of additional progress in economic science, The General Theory is an outdated book. . . . We are in a much better position than Keynes was to figure out how the economy works.”

adaWe have learned since [2008] that the present generation of economists has not figured out how the economy works …

Baffled by the profession’s disarray, I decided I had better read The General Theory. Having done so, I have concluded that, despite its antiquity, it is the best guide we have to the crisis …

It is an especially difficult read for present-day academic economists, because it is based on a conception of economics remote from theirs. This is what made the book seem “outdated” to Mankiw — and has made it, indeed, a largely unread classic … The dominant conception of economics today, and one that has guided my own academic work in the economics of law, is that economics is the study of rational choice … Keynes wanted to be realistic about decision-making rather than explore how far an economist could get by assuming that people really do base decisions on some approximation to cost-benefit analysis …

Economists may have forgotten The General Theory and moved on, but economics has not outgrown it, or the informal mode of argument that it exemplifies, which can illuminate nooks and crannies that are closed to mathematics. Keynes’s masterpiece is many things, but “outdated” it is not.

Richard Posner

Si dolce è il tormento

10 Jul, 2016 at 11:31 | Posted in Varia | Comments Off on Si dolce è il tormento


Pastoral in the Forest

10 Jul, 2016 at 11:14 | Posted in Varia | Comments Off on Pastoral in the Forest


Krugman’s dangerous lack of methodological reflection

9 Jul, 2016 at 13:37 | Posted in Economics | 11 Comments

How do we do useful economics?

This is an important question that every earnest economist ought to pose — and try to answer.

Here’s one answer, from Nobel laureate Paul Krugman:

In general, what we really do is combine maximization-and-equilibrium as a first cut with a variety of ad hoc modifications reflecting what seem to be empirical regularities about how both individual behavior and markets depart from this idealized case.

For everyone who knows at least a little of contemporary economics, it’s pretty obvious that this is actually not very different from the way economics is supposed to be advancing according to the New Classical school in Chicago. And just as Chicago boys like Lucas and Sargent, Krugman doesn’t give the slightest hint on when (and how) the the gap between the ‘idealized’ models with their unreal assumptions of perfectly rational individuals and markets gets so big that the models become useless nonsense.


One of the most important things that Krugman and other mainstream neoclassical economists trivialize, or do not want to admit, is the ubiquity of genuine uncertainty. And this is, of course, not by chance. The more uncertainty there is in the economy, the less possibilities are there for any ‘maximization’ going on in any ‘stable equilibria’!

Krugman’s view should come as no surprise for those who took part of Krugman’s response to my critique of IS-LM. Krugman works with a very simple modelling dichotomy — either models are complex or they are simple. For years now, self-proclaimed ‘proud neoclassicist’ Paul Krugman has in endless harpings on the same old IS-LM string told us about the splendour of the Hicksian invention — so, of course, to Krugman simpler models are always preferred.

When it comes to modeling philosophy, Paul Krugman has in an earlier piece defended his position in the following words (my italics):

I don’t mean that setting up and working out microfounded models is a waste of time. On the contrary, trying to embed your ideas in a microfounded model can be a very useful exercise — not because the microfounded model is right, or even better than an ad hoc model, but because it forces you to think harder about your assumptions, and sometimes leads to clearer thinking. In fact, I’ve had that experience several times.

The argument is hardly convincing. If people put that enormous amount of time and energy that they do into constructing macroeconomic models, then they really have to be substantially contributing to our understanding and ability to explain and grasp real macroeconomic processes. If not, they should – after somehow perhaps being able to sharpen our thoughts – be thrown into the waste-paper-basket, and not as today, being allowed to overrun our economics journals and giving their authors celestial academic prestige.

Krugman has in more than one article criticized mainstream economics for using too much (bad) mathematics and axiomatics in their model-building endeavours. But when it comes to defending his own position on various issues he usually himself ultimately falls back on the same kind of models. In his End This Depression Now — just to take one example — Paul Krugman maintains that although he doesn’t buy ‘the assumptions about rationality and markets that are embodied in many modern theoretical models, my own included,’ he still find them useful ‘as a way of thinking through some issues carefully.’

When it comes to methodology and assumptions, Krugman obviously has a lot in common with the kind of model-building he otherwise criticizes.

If macroeconomic models – no matter of what ilk – make assumptions, and we know that real people and markets cannot be expected to obey these assumptions, the warrants for supposing that conclusions or hypotheses of causally relevant mechanisms or regularities can be bridged, are obviously non-justifiable. Macroeconomic theorists – regardless of being New Monetarist, New Classical or ‘New Keynesian’ – ought to do some methodological reflection and heed Keynes’ warnings on using thought-models in economics:

The+General+Theory+of+Employment,+Interest,+and+MoneyThe object of our analysis is, not to provide a machine, or method of blind manipulation, which will furnish an infallible answer, but to provide ourselves with an organized and orderly method of thinking out particular problems; and, after we have reached a provisional conclusion by isolating the complicating factors one by one, we then have to go back on ourselves and allow, as well as we can, for the probable interactions of the factors amongst themselves. This is the nature of economic thinking. Any other way of applying our formal principles of thought (without which, however, we shall be lost in the wood) will lead us into error.

The truth about banks

7 Jul, 2016 at 11:26 | Posted in Economics | 11 Comments

When faced with the Great Recession in 2008, macroeconomics was initially unprepared to contribute much to the analysis of the interaction of banks with the macro economy. Today there is a sizable body of research on this topic, but the literature still has many difficulties …

In modern neoclassical intermediation of loanable funds theories, banks are seen as intermediating real savings. Lending, in this narrative, starts with banks collecting deposits of previously saved real resources (perishable consumer goods, consumer durables, machines and equipment, etc.) from savers and ends with the lending of those same real resources to borrowers. But such institutions simply do not exist in the real world. There are no loanable funds of real resources that bankers can collect and then lend out. Banks do of course collect checks or similar financial instruments, but because such instruments—to have any value—must be drawn on funds from elsewhere in the financial system, they cannot be deposits of new funds from outside the financial system. New funds are produced only with new bank loans (or when banks purchase additional financial or real assets), through book entries made by keystrokes on the banker’s keyboard at the time of disbursement. This means that the funds do not exist before the loan and that they are in the form of electronic entries—or, historically, paper ledger entries—rather than real resources.­

kumhof_chartThis process, financing, is of course the key activity of banks. The detailed steps are as follows. Assume that a banker has approved a loan to a borrower. Disbursement consists of a bank entry of a new loan, in the name of the borrower, as an asset on its books and a simultaneous new and equal deposit, also in the name of the borrower, as a liability. This is a pure bookkeeping transaction that acquires its economic significance through the fact that bank deposits are the generally accepted medium of exchange of any modern economy, its money. Clearly such transactions—which one of us has personally witnessed many times as a corporate banker—involve no intermediation whatsoever …

Many policy prescriptions aim to encourage physical investment by promoting saving, which is believed to finance investment. The problem with this idea is that saving does not finance investment, financing and money creation do. Bank financing of investment projects does not require prior saving, but the creation of new purchasing power so that investors can buy new plants and equipment. Once purchases have been made and sellers (or those farther down the chain of transactions) deposit the money, they become savers in the national accounts statistics, but this saving is an accounting consequence—not an economic cause—of lending and investment. To argue otherwise is to confuse the respective macroeconomic roles of real resources (saving) and debt-based money (financing). Again, this point is not new; it goes back at least to Keynes (Keynes, 2012). But it seems to have been forgotten by many economists, and as a result is overlooked in many policy debates.­

Michael Kumhof and Zoltán Jakab

On the scaling property of randomness (wonkish)

7 Jul, 2016 at 00:16 | Posted in Economics | 1 Comment

I thought hard and long on how to explain with as little mathematics as possible the difference between noise and meaning, and how to show why the time scale is important in judging an historical event. The Monte Carlo simulator can provide us with such an intuition. We will start with an example borrowed from the investment world …

no_signal_all_noise_fullLet us manufacture a happily retired dentist, living in a pleasant sunny town. We know a priori that he is an excellent investor, and that he will be expected to earn a return of 15% in excess of Treasury bills, with a 10% error rate per annum (what we call volatility). It means that out of 100 sample paths, we expect close to 68 of them to fall within a band of plus and minus 10% around the 15% excess return, i.e. between 5% and 25% (to be technical; the bell-shaped normal distribution has 68% of all observations falling between —1 and 1 standard deviations). It also means that 95 sample paths would fall between —5% and 35% …

A 15 % return with a 10 % volatility (or uncertainty) per annum translates into a 93% probability of making money in any given year. But seen at a narrow time scale, this translates into a mere 50.02% probability of making money over any given second. Over the very narrow time increment, the observation will reveal close to nothing …

This scaling property of randomness is generally misunderstood, even by professionals. I have seen Ph.D.s argue over a performance observed in a narrow time scale (meaningless by any standard) …

The same methodology can explain why the news (the high scale) is full of noise and why history (the low scale) is largely stripped of it (though fraught with interpretation problems).

Nassim N. Taleb

And it actually gets even worse if we leave the ‘certainty’ of Monte Carlo simulations and get in to reality. Since return volatilities often follow different scaling laws at different horizons, there is no way of simply converting short horizon ‘risks’ into long horizon ‘risks’ by using a universal scaling parameter (unless you assume the data distribution is iid, which, of course, it is not if we are talking about financial time series data).


61EYsF5EIyLIn my view, regression models are not a particularly good way of doing empirical work in the social sciences today, because the technique depends on knowledge that we do not have. Investigators who use the technique are not paying adequate attention to the connection – if any – between the models and the phenomena they are studying. Their conclusions may be valid for the computer code they have created, but the claims are hard to transfer from that microcosm to the larger world …

Regression models often seem to be used to compensate for problems in measurement, data collection, and study design. By the time the models are deployed, the scientific position is nearly hopeless. Reliance on models in such cases is Panglossian …

Causal inference from observational data presents may difficulties, especially when underlying mechanisms are poorly understood. There is a natural desire to substitute intellectual capital for labor, and an equally natural preference for system and rigor over methods that seem more haphazard. These are possible explanations for the current popularity of statistical models.

Indeed, far-reaching claims have been made for the superiority of a quantitative template that depends on modeling – by those who manage to ignore the far-reaching assumptions behind the models. However, the assumptions often turn out to be unsupported by the data. If so, the rigor of advanced quantitative methods is a matter of appearance rather than substance.

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