Tag Archives: G&L

Credit And Economic Growth

In a new column for Bloomberg, Noah Smith questions the intuition that credit fuels economic growth.

He says:

It seems like the only people who don’t instinctively believe in credit-fueled growth are academic economists.

The academics have good reason for being skeptical.

His reason (in short) is the following:

It’s pretty obvious how credit drives my personal household consumption. If I borrow, I can get a nice big TV and a new car, but eventually I’ll have to skimp to pay it back. In a way, the consumption-fueled borrowing binge is an illusion of wealth — after all, borrowing doesn’t increase my salary. Pleasure today means pain tomorrow.

Notice how Smith’s argument uses a lot of national accounting and flow of funds concepts: consumption, borrowing, wealth, repayment (of loans) and so on. The interesting thing is that one can use the system of national accounts and flow of funds to create models which show precisely the opposite of what Smith is saying. The best place obviously to look out for is the book Monetary Economics: An Integrated Approach to Credit, Money, Income, Production and Wealth by Wynne Godley and Marc Lavoie which has models called stock-flow consistent models or SFC models. It is however difficult to write down a simple SFC model in a blog post, so I will try to highlight how it works in words but refer the reader to these models.

Here’s how in a simple model:

  1. Consumers decide to borrow more and banks respond by granting them loans.
  2. Consumers spend the funds received on consumption goods.
  3. Since loans make deposits, it’s not as if someone forgoes consumption to lend as neoclassical textbooks say.
  4. Firms see their inventories go down and respond by increasing their inventories by producing more.
  5. For producing more, firms hire more labour and pay salary/compensation.
  6. People newly employed spend their income and there’s further rise in production as firms produce more when seeing a higher demand for their products.
  7. Higher production leads to a rise in productivity and wages/household incomes of the already employed rise in response (although not necessarily the case).

So we have a higher output than what we started with and higher national income.

One can take several issues with this and this is one reasons models are really helpful and pinpoint what’s going on. This is the reason I referred to the book by Godley and Lavoie above. So for example, one can ask: what if the rise in the national income and output is just a rise in the nominal value but that it’s possible that prices have changed and that the real output hasn’t changed. This of course needs a model of prices and inflation but a familiarity with stock-flow consistent models will make you realize that it is an extreme assumption to think that the real output hasn’t risen in the sequence of events highlighted above.

The second thing is the above “model” in words had just banks lending to households whereas in the real world, credit (as in any credit, such as firms borrowing) is via credit markets of which banks are only one part. This issue is not so simple to argue out, but it can be shown that it really doesn’t matter (in the first approximation). I do not know how to quickly argue it out in short here but will leave that for now.

Of course the above model can be misleading. For example, if households take a lot of debt, debt repayment burden will hit and cause a slowdown as households’ consumption will drop and this may lead to an economic slowdown. This point may look similar to what Noah Smith is saying, but that is not the case. One can imagine an economy starting with a GDP of 100 and growing to 120 in some time period and then slowing down to 118 because of the debt burden. Also the above model was implicitly a pure private sector model and in general one has both the government and the overseas sector adding more complications. Again more reasons why having a proper mathematical model for such things is important.

Another critique of Smith (in my mini-exchange of tweets with him on Twitter) was that SFC models do have behavioural assumptions. I agree, but my point was that there’s no reason to dismiss the argument “credit fuels growth” by purely theoretical arguments. If at all, the system of national income and flow of funds make it more convincing that credit is important.

Of course none of this means that policies should be promoted to ease credit conditions always and try to create a boom and what Smith says is somewhat true – there can be pain later, so it is important to consider fiscal policy, balance of payments and so on but the story told here is quite different from the one told by Noah Smith.

Keen’s Reply To Palley

Steve Keen has replied to Thomas Palley’s critique of him with an article How not to win an economic argument.

All models are incomplete because they ignore many complications in order to highlight a few key concepts. In other times, a simple model is a starting point with the aim that the modeler adds more complications to make it more realistic. So it is sometimes not a good critique to point out what the models misses. But Steve Keen is making it look as if Palley’s critique is of what his models do not have.

This is diverting attention. For about two years or more, Keen has given all sorts of definitions of aggregate demand. The reason Palley’s critique is so solid is that it again points out that Keen’s definitions are wrong. Keen has repeated statements on aggregate demand and “change in debt” many times, making it sound like a universal law. Palley has shown via very straightforward arguments as quoted in my previous post Thomas Palley’s Nice Critique Of Steve Keen’s Models that the definition is incorrect. Moreover, Keen has changed his definitions as highlighted by a nice blog article by JKH. In my opinion Keen himself is confused on which definition is right and uses all of them together many times without realizing that they are different. His earlier definitions were simply incorrect on basic flow of funds accounting.

In short, there is no simple expression for changes in aggregate demand with changes in debt, a point mentioned by Nick Edmonds on his blog. Even if not, one could argue that it is useful but that is not the case because even at the theoretical level, there are conceptual issues, a lot because Keen doesn’t do his accounting right. Such things are not mere technicalities but the concepts of flow of funds is highly important to make some progress in analytic modeling.

Keen says:

My approach was to take the other side’s model, and show that if their assumptions were correct, they were right: banks could be ignored in macroeconomics, and changes in private debt had only a miniscule effect on demand.

Then I made one realistic small change, and hey presto — banks were essential to macroeconomics, and changes in private debt were the main game (but not the only one) in changing aggregate demand.

True neoclassical economists do not incorporate money and debt in their analysis but Keen has all this while given hints that Post-Keynesians themselves have not if you see his videos. Even the above quotes suggests as if nobody has done this before Keen. That coupled with the fact that Keen considers anyone having issues his models to be sinful of the loanable funds model. There is an irony here because Keen himself makes errors of the loanable funds approach when distinguishing bank debt and non-bank debt.

In my opinion Keen should completely get rid of this aggregate demand/change in debt slogan. Rejection of this does not mean debt is unimportant and all that. There are nice and realistic models such as that of Wynne Godley and Marc Lavoie (G&L) in which money and credit are central to the analysis and with no need at all for Keen’s fondness of aggregate demand/change in debt. These models have a very important role for aggregate demand and credit and feedback effects and so on but there is no need for inventing new definitions.

Neither is there any need for Lebesgue integrals. If one repeats Keen’s analysis where an economic unit pays for a good with a debit card or cash instead of a credit card, then it violates his own aggregate demand/change in debt definitions.

Some Nice Words On Wynne Godley And Monetary Economics

I am reading this book The Oxford Handbook of Post-Keynesian Economics, Volume 1: Theory and Origins and it has some nice chapters!

In his chapter Postkeynesian Precepts For Nonlinear, Endogenous, Nonstochastic, Business Cycle Theories, K. Vela Velupillai has some nice words on Wynne Godley and his book Monetary Economics co-authored with Marc Lavoie:

K Vela Velupillai On Wynne Godley(snipping via amazon.com)

Flow Of Funds And Keynesian Macroeconomics

The subject of money, credit and moneyflows is a highly technical one, but it is also one that has a wide popular appeal. For centuries it has attracted quacks as well as serious students, and there has too often been difficulty in distinguishing a widely held popular belief from a completely formulated and tested scientific hypothesis.

I have said that the subject of money and moneyflows lends itself to a social accounting approach. Let me go one step farther. I am convinced that only with such an approach will economists be able to rid this subject of the quackery and misconceptions that have hitherto been prevalent in it.

– Morris Copeland, inventor of the Flow Of Funds Accounts of the United States, in Social Accounting For Moneyflows, in Flow-of-Funds Analysis: A Handbook for Practitioners (1996) [article originally published in 1949]

Alas monetary myths continue to exist. The above referred handbook was published in 1996 starting with Copeland’s 1949 article and the editor of the book John Dawson himself had an explanation of why myths continue to exists despite some brilliant work such as that of Copeland. In page xx, Dawson says:

the acceptance of… flow-of-funds accounting by academic economists has been an uphill battle because its implications run counter to a number of doctrines deeply embedded in the minds of economists.

In a recent blog post blog post Paul Krugman is dismissive of Wynne Godley’s approach to macro modeling and instead appeals to some Friedmanism. Perhaps Dawson’s quote explains why this is so. However it may not be the only reason, given how Krugman has shown some tendency to be heteredox in recent times but his latest post ends all doubts and we can say he is highly orthodox. And that other reason is professional turf-defence.

Also, Krugman was writing in response to an NYT article Embracing Wynne Godley, an Economist Who Modeled the Crisis highlighting the importance of Wynne Godley’s work. That article was by a journalist who was perhaps unaware of the history of Post-Keynesianism. But Krugman himself dodged Godley’s work as “old-fashioned” – as if there is something fundamentally wrong about old-fashion and as if economics should proceed by one fashion after another.

A bigger disappointment is that Krugman failed to acknowledge that there has existed a heteredox approach since Keynes’ time. As Wynne Godley and Marc Lavoie begin Chapter 1 in their book Monetary Economics:

During the 60-odd years since the death of Keynes there have existed two, fundamentally different, paradigms for macroeconomic research, each with its own fundamentally different interpretation of Keynes’ work…

And Krugman’s usage of the phrase old-fashioned hides the fact that this is so.

Back to Copeland. In the same article Social Accounting For Moneyflows, Copeland is clear about his intentions and the direction he is looking:

When total purchases of our national product increase, where does the money come from to finance them? When purchases of our national product decline, what becomes of the money that is not spent? What part do cash balances, other liquid holdings, and debts play in the cyclical expansion of moneyflow?

Copeland’s analysis was not simply theoretical. It led to the creation of the flow of funds accounts of the United States and the U.S. Federal Reserve publishes this wonderful data book every quarter. Although, Copeland was simply looking and proceeding in the right direction, it can be said that a more solid theoretical framework to build upon Copeland’s brilliant work was still waiting at the time.

Of course, in the world of academics, there already existed two main schools of thought very hostile to one another. Keynes’ original work contained a lot of errors and for most economists, a bastardised version of Keynes’ work became the popular understanding. It was however the Cambridge Keynesians who founded the school Post-Keynesian Economics who believed they were true to the spirit of Keynes and this led to a parallel body of extremely high-quality intellectual work which continues to this day – and still dismissed by economists such as Paul Krugman. Of course, in this story, it should be mentioned that there was a Monetarist counter-revolution mainly led by Milton Friedman who was trying to bring back the old quantity theory of money doctrines and was “successful” in permanently distorting the minds of generations of economists to date. Greg Mankiw is quite straight on this and according to him, “New Keynesian” in the “New Keynesian Economics” is a misnomer and it should actually be New Monetarism.

Interestingly, one of Morris Copeland’s ideas was to show how the quantity theory of money is wrong. According to Dawson (in the same book referred above):

[Copeland] himself was at pains to show the incompatibility of the quantity theory of money with flow-of-funds accounting.

Meanwhile, in the 1960s and to the end of his life, James Tobin tried to connect Keynesian economics with the flow of funds accounts. While a lot of his work is the work of a supreme genius, he couldn’t manage. Perhaps it was because of his neoclassical background which may have come in the way. According to his own admission, he couldn’t connect the dots:

Monetary and financial data, so far as they are based on institutional balance sheets and prices in organized markets, are abundant. Modern machines have made it possible to improve, refine and expand the compilation of these data, and also to seek empirical regularities in financial behavior in the magnitude of individual observations. On the aggregate level, the Federal Reserve Board has developed a financial accounting framework, the “flow of funds,” for systematic and consistent organization of the data, classified both by sector of the economy (households, nonfinancial business, governments, financial institutions and so on) and by type of asset or debt (currency, deposits, bonds, mortgages, and so on). Although many people hope that this organization of data will prove to be as powerful an aid to economic understanding as the national income accounts, this hope has not yet been fulfilled. Perhaps the deficiency is conceptual and theoretical; as some have said, the Keynes of “flow of funds” has yet to appear.

– James Tobin in Introduction (pp xii-xiii) in Essays In Economics, Volume 1: Macroeconomics, 1987.

After having written a fantastic book Macroeconomics with Francis Cripps in 1983 and which has connections with the flow of funds, Wynne Godley thought he had to try hard to unify (post-)Keynesianism and the flow of funds approach which James Tobin was trying. Wynne Godley had the advantage of being close to Nicholas Kaldor who very well understood the importance of Keynes and was himself an economist of Keynes’ rank. Godley also had the advantage of having worked for the U.K. government and doing analysis using national accounts data and advising policy makers. Wynne Godley is the Keynes of “flow of funds” which Tobin was talking about!

A recent blog post by Matias Vernengo on Wynne Godley is extremely well-written.

In his later years (and his best), Wynne Godley worked with Marc Lavoie, one of the faces of Post-Keynesianism and one who had previously made highly original contributions to Post-Keynesianism and this led to the book Monetary Economics. Marc’s earlier work was also highly insightful and he highlighted – in the spirit of Morris Copeland – how poorly money is understood by economists in general and it was natural he and Wynne would meet and work together.

One of the things about Wynne Godley’s approach is how to combine abtract theoretical work and direct practical economic issues. This actually led him to warn of serious deflationary consequences of economic policy in fashion before the crisis.

Lance Taylor (in A Foxy Hedgehog: Wynne Godley And Macroeconomic Modelling) had a nice way to describe Wynne Godley:

Wynne has long been aware of the stupidity of models when you ask them to say something useful about practical policy problems. He has spent a fruitful career trying to make models more sensible and using them to support his policy analysis even when they are obtuse. As we have seen, this quest has led him to many foxy innovations.

But there is an enduring hedgehog aspect as well. Wynne has focused his energy on combining the models with his acute policy insight based on deep social concern to build up a large and internally coherent body of work. He has disciples and is widely influential. One might wish that he had pursued some lines of analysis more aggressively and perhaps put a bit less effort into others. And maybe not have written down so damn many equations. But these are quibbles. His work is inspiring, and will guide policy-oriented macroeconomic modellers for decades to come.

In this post, I have tried to provide the reader with references to go and verify how flow of funds1 cannot be separated from Keynesian Economics – Keynesian approach in the original spirit of Keynes, not some bastartized versions. It is as if they were made for each other2. While it is true that like other sciences, Macroeconomics is always work in progress, it doesn’t mean one should bring fashions such as inter-temporal utility maximising agents (read: future knowing economic actors) in the approach which Paul Krugman prefers.

1My usage of “flow of funds” is more generic than the usage which distinguishes income accounts and flow of funds accounts and hence my usage is for both.

2The ties between the flow of funds approach and Post-Keynesiansism is argued in Godley and Lavoie’s book Monetary Economics from which I have borrowed a lot.

Correction (18 Sep 2013 4:05am  GMT)

I am mistaken about Jonathan Schlefer’s background. He is in academics.

The Rate Of Saving In Wynne Godley’s Models [Updated]

In Krugman’s blog post which is dismissive of Wynne Godley’s work (referred in my previous post) he (Krugman) makes the following claim:

First involved consumption spending. Conventional Keynesian consumption functions suggested that the savings rate would rise as incomes rose — and this wasn’t just the Keynesian interpreters, Keynes himself made the same claim.

which shows that Krugman has less clue about what he talks. Funny, the profession is ruled by clowns like him.

In Wynne Godley’s models, there is a propensity to consume out of income and out of wealth – represented in his models by the parameters αand αand the rate of saving in any period is given by the model. So in the simplest model – for example in Godley’s book with Marc Lavoie Monetary Economics, the rate of saving can has the following dynamic:

Disposable Income - G&L

Rate Of Saving - G&L

(image screenshot via amazon.com “Look Inside”)

(Note: In the above model, money is the only asset). This is starting from scratch but similar behaviour can be seen if one starts with some initial self-consistent configuration.

This is contrary to what Paul Krugman claims of Keynesian models. The above shows how the rate of saving first rises and then starts to fall and this whole adjustment will happen with a time lag given by a “stock-flow norm” and can be fast.

The reason it happens is simple. It is clear Krugman doesn’t realize the underlying stock-flow dynamics. As households’ saving and income rises because of a rise in government expenditure, they are also accumulating wealth. So a scenario where saving rises forever is meaningless because they would start consuming from their wealth as well.

Krugman continues:

This, in turn, led to predictions of rising savings rates after World War II, and hence a persistent shortage of demand — hence the secular stagnation theory briefly prominent. (There was even an early Heinlein novel built in part around the secular stagnation theory. As I recall, it was pretty bad.)

which is quite wrong – as stock-flow consistent dynamics suggests otherwise.

I’ll hold it to make any generic statements but it is clear that Krugman doesn’t know a thing or two about Keynesian Macroeconomics :-)


Many times standard textbooks use a Keynesian consumption function of the form

C = α0 + α1·YD

where C is the consumption, and YD is the disposable income.

It is then easy to see that C/YD decreases with YD and this is what Krugman is talking of.

However only slight improved modification where the consumption function depends on wealth as well leads to a different behaviour as highlighted in the main text. So it is strange Krugman dismisses consumption functions and instead talks of “failures that it seemed could have been avoided by thinking more in maximizing terms” !

*I thank Nick Edmonds in pointing this out.

Last Updated 14 Sep 2013 9:35am GMT

NYT On Wynne Godley

There’s a nice new article on Wynne Godley today in The New York Times.

An interesting thing in the article is the mention of intuition via models while mentioning his book Monetary Economics.

Why does a model matter? It explicitly details an economist’s thinking, Dr. Bezemer says. Other economists can use it. They cannot so easily clone intuition.

That is so right. The models in the books of Wynne Godley – both Monetary Economics with Marc Lavoie and Macroeconomics with Francis Cripps give a good idea about the authors’ intuitions. Of course, needless to say the man was bigger than his models.

Wynne Godley - NYT

Random Tidbits On National Accounts And Keynesian Models Of Income And Expenditure

I came across this article (via a Tweet from Stephen Kinsella): Accounting As The Master Metaphor Of Economics by Arjo Klamer and Donald McCloskey which discusses how the framework of national accounts has been pushed to the background in economic analysis over the years.

It is a nice read – although boring in a few places. I found this reference to John Hicks’ 1942 book The Social Framework: An Introduction To Economics in the above article and managed to get a copy – although a used one but with almost no usage. As described in the Klamer-McCloskey’s article, Hicks’ textbook really goes into details of national accounts and he seems to have had a great intuition of how it all works.

John Hicks - The Social Framework

Hicks’s book gives a nice introduction to how important national accounts are in understanding and describing the production process and economic cycles.

Here is a scan of two pages on the balance of payments – the topic I like the most.

John Hicks Balance Of Payments

(click to enlarge)

Hicks understood how weak balance of payments can cause troubles. Of course, it took the genius of Nicholas Kaldor to realize the supreme importance of balance of payments in the determination of national income and expenditure. Leaving that aside, the text has nice ideas and discussions on how stocks and flows feed into one another.

John Hicks is famous for an entirely different reason – the IS/LM model. Later he accepted it was a huge mistake, but put it mildly: “… as time as gone on, I have myself become dissatisfied with it”. But economists still keep using it and keep erring.

Also, Hicks was to soon abandon/forget his own social accounting approach as per Klamer-McCloskey’s article. Perhaps, not really.

In an extremely important paper, Wynne Godley said:

To come down to it, the present paper claims to have made, so far as I know for the first time, a rigorous synthesis of the theory of credit and money creation with that of income determination in the (Cambridge) Keynesian tradition. My belief is that nothing the paper contains would have been surprising or new to, say, Kaldor, Hicks, Joan Robinson or Kahn.

John Hicks also had another nice book called A Market Theory Of Money written in 1989. Here is a great insight (also the view of Kaldor) from Page 11, Chapter 1 named “Supply And Demand?” on how to create a dynamic Keynesian theory of determination of national income and expenditure:

… The traditional view that market price is, at least in some way, determined by an equation of demand and supply had now to be given up. If demand and supply are interpreted, as had formerly seemed to be sufficient, as flow demands and supplies coming from outsiders, it is no longer true that there is any tendency over any particular period, for them to be equalized: a difference between them, if it were not too large, could be matched by a change in stocks. It is of course true that if no distinction is made between demand from stockholders and demand from outside the market, demand and supply in that inclusive sense  must be equal. But that equation is vacuous. It cannot be used to determine price, in Walras’ or Marshall’s manner. For what matters to the stockholder is the stock that he is holding: the increment in that stock, during a period is the difference between what is held at the end and what was held at the beginning, and the beginning stock is carried over from the past. So the demand-supply equation can only be used in a recursive manner, to determine a sequence (It is a difference or a differential equation); it cannot be used directly to determine price, as Walras and Marshall had used it.

I came across a reference in the book (The Social Framework) to a paper by James Meade and Richard Stone on concepts on national accounts: The Construction Of Tables Of National Income, Expenditure, Savings And Investment written in 1941. It has the following interesting table:

James Meade & Richard Stone - Sectoral Balances

which is the now famous sectoral balances identity! Incidentally, it also includes Kalecki’s profit equation. In the above “Foreign Investment” shouldn’t be confused with Foreign Direct Investment flows in the financial account of the balance of payments. The authors define it as:

… equal to income generated by receipts from abroad less current expenditure abroad.

So can we call the profit equation SMK equation? :-)

James Meade and Richard Stone were pioneers of national accounts. Incidentally, James Meade wrote a famous textbook on balance of payments.

Of course the way this is presented doesn’t make the connection between the financial account and current accounts. The sectoral balances was usually written by Wynne Godley as:


where NAFA is the net accumulation of financial assets of the private sector, PSBR is the net public sector borrowing requirement, and BP is the current account balance of international payments. More on this connection below.

How it is to be derived in a stock-flow consistent framwork of Godley/Lavoie? If you click on this search Transactions Flow Matrix, you will find some blog posts on the background. First, we construct a flow matrix like this:

Simplified National Income Matrix

The last line is essentially Kalecki’s profit equation.

The above construction however raises an important question. Godley and Lavoie’s textbook (Chapter 2) quotes a famous 1949 article of Morris Copeland on this:

When total purchases of our national product increase, where does the money come from to finance them? When purchases of our national product decline, what becomes of the money that is not spent?

Copeland’s work was highly successful and established the flow of funds accounts of the United States in 1952.

Here is a republished version of the article (via Google Books):


If you prefer Google Books directly, here is the link: Social Accounting For Moneyflows.

Incidentally, Copeland was motivated to prove the quantity theory of money wrong when he did this work! Also Godley/Lavoie point out that John Dawson (the editor of the above book) says:

the acceptance of…flow-of-funds accounting by academic economists has been an uphill battle because its implications run counter to a number of doctrines deeply embedded in the minds of economists.

in an article from the chapter The Conceptual Relation Of Flow-Of-Funds Accounts To The SNA of the same book.

Over time, the system of national accounts (with its first version in 1947) has used some of the concepts of flow of funds accounting and now the framework is much more wider than usual textbook guides of national accounts. The flow of funds still retains importance because it has information which the system of national accounts such as (2008 SNA) doesn’t handle.

Here’s the UN website for the historical versions of the system of national accounts.

How does one look at this in a stock-flow coherent framework? Simple, we need a full transactions flow matrix – which not only includes income/expenditure flows but also financial flows. The following is how it looks like for a simple model:

Transactions Flow Matrix 3

(Click to zoom)

Of course, identities themselves shouldn’t be looked at as models. One needs a fully coherent accounting model of the economy based on behavioural assumptions and “closures”. See this essay Keynesian theorising during hard times: stock-flow consistent models as an unexplored ‘frontier’ of Keynesian macroeconomics Camb. J. Econ. (July 2006) 30(4): 541-565 by Claudio Dos Santos and also Wynne Godley and Marc Lavoie’s book Monetary Economics. As Dos Santos quotes Lance Taylor in the article:

Formally, prescribing a closure boils down to stating which variables are endogenous or exogenous in an equation system largely based upon macroeconomic accounting identities, and figuring out how they influence one another.

Origins Of The Sectoral Balances Identity

I thought I should share what I found recently about who was to state the sectoral balances identity first – since it comes across as enlightening to say the least. I found the identity in Nicholas Kaldor’s 1944 article Quantitative Aspects Of The Full Employment Problem In Britain. It was published as Appendix C to Full Employment In A Free Society by William Beveridge.

(If you find the mention of this identity anywhere before, please let me know!)

Here’s a Google Books screenshot of the page:

The article also appears in Kaldor’s Collected Essays, Vol 3 (Chapter 2, pp. 23-82).

The ‘net’ is net of consumption of fixed capital. Also ‘balance of payments’ is used for the current balance (footnote 1, page 28). (In The Scourge Of Monetarism, Kaldor used ‘net saving’ as saving net of investment).

Anthony Thirlwall wrote a biography of Kaldor in 1987 and he mentions that Kaldor kept pushing the implications of the identity in the 1960s (page 251). He managed to convinced some of his colleagues such as Wynne Godley and Francis Cripps and pick up public fights with others such as Richard Kahn.

Wynne Godley recalled how he came to appreciate this identity in his book Monetary Economics with Marc Lavoie. In Background Memories (W.G.) he wrote:

… In 1970 I moved to Cambridge, where, with Francis Cripps, I founded the Cambridge Economic Policy Group (CEPG). I remember a damascene moment when, in early 1974 (after playing round with concepts devised in conversation with Nicky Kaldor and Robert Neild), I first apprehended the strategic importance of the accounting identity which says that, measured at current prices, the government’s budget deficit less the current account deficit is equal, by definition, to private saving net of investment. Having always thought of the balance of trade as something which could only be analysed in terms of income and price elasticities together with real output movements at home and abroad, it came as a shock to discover that if only one knows what the budget deficit and private net saving are, it follows from that information alone, without any qualification whatever, exactly what the balance of payments must be. Francis Cripps and I set out the significance of this identity as a logical framework both for modelling the economy and for the formulation of policy in the London and Cambridge Economic Bulletin in January 1974 (Godley and Cripps 1974). We correctly predicted that the Heath Barber boom would go bust later in the year at a time when the National Institute was in full support of government policy and the London Business School (i.e. Jim Ball and Terry Burns) were conditionally recommending further reflation! We also predicted that inflation could exceed 20% if the unfortunate threshold (wage indexation) scheme really got going interactively. This was important because it was later claimed that inflation (which eventually reached 26%) was the consequence of the previous rise in the ‘money supply’, while others put it down to the rising pressure of demand the previous year …

The α2 Parameter In Stock-Flow Consistent Models

Let us think of a closed economy. Assuming – every year the government runs a budget deficit – a careless analysis would imply the public debt keeps rising relative to gdp.

Without going into derivation – which you can find in other sources – it can be shown that if there is a growth rate of g, the public debt converges to

GD/Y = (PDEF/Y)/(gr)

where GD is the government debt, Y – the national income, PDEF – the primary government deficit (government expenditure excluding interest payments less tax revenues) and g and r are the nominal growth rates and the interest rate respectively.

Several things. The above assumes – implicitly – that DEF is a constant percent of GDP (Y). Second, it neglects the fact that interest income is also income to bond holders which leads to more consumption. Third, less importantly, it ignores taxes on interest income. The first one is important. There is an implicit assumption of the exogeneity of the budget deficit and the above expression has nothing to say about the private sector’s propensity to save, consume etc.

The above expression has been derived using the assumption that g > and summing a series. For the opposite case, the series used to derive it diverges. [For example, the equation

1 + x + x2 + x3 + … = 1/(1 – x)

is valid only if x < 1. For x > 1, the left hand side diverges and not negative as the formula implies!]

This has led authors to argue that if the growth rate is higher than the average interest rate paid on government debt, then the public debt doesn’t rise forever.

This intuition is not so right – although there is an element of truth in it but needs to be used extremely carefully.

Wynne Godley and Marc Lavoie [1] (but also [2] – which I haven’t managed to get hold of) show what this “stock-flow norm” converges asymptotically in the case of a very simple model of a closed economy – even when the government is not targeting a primary surplus in the budget.  The following are from their paper and the lower case is used to denote real variables instead of nominal: 

In the above gd is the real government debt, is the real national income, αis the propensity of households to consume out of disposable income, α2 is the propensity to consume out of wealth, gr is the growth rate of output, rr is the real interest rate, π  is the rate of inflation and θ is the tax rate.

The assumed consumption function is:

where c is real consumption,  yd is household real disposable income, and v is real household wealth.

 This expression gives some intuition. The growth rate can be quite less than the interest rate and yet the public debt can be bounded. This is because bond interest payments by the government is income for bond holders. More importantly, the denominator contains α2 which significantly brings the (public debt/gdp) ratio down (compared to the case where α2 is zero).

Looking at the model and how the variables change, one can conclude that the government needn’t pursue a policy of targeting a primary surplus, contrary to the intuition neoclassical economists obtain by doing debt sustainability analysis. The budget may reach a primary surplus automatically as a result of higher taxes due to higher activity.

Also, there is no condition “g > r”. 

One may wonder what value the parameter α2 has for various economies. According to Lance Taylor – a reviewer of Wynne Godley’s work [3] –  the value could be 0.04 or 4% from econometric studies but he does notice the tendency of G&L to choose a higher value in pedagogic examples.

In my opinion it is higher. I think it’s a good challenge to try to show this empirically. This may be true because (abstracting out the effect of the external sector, the public debt ratio is better explained and also that a high α2 implies a quick response to a fiscal expansion – which is true.

One should be highly careful about debt sustainability analysis. For the case of an open economy, while it is true that a debtor nation can be a debtor forever under some assumptions, achieving a faster growth in a world of free trade can lead to stock/flow ratios rising forever instead of converging. Which is to say that nations are balance-of-payments constrained.


  1. Wynne Godley and Marc Lavoie, Fiscal Policy In A Stock-Flow Consistent Model, p 79, Journal of Post Keynesian Economics / Fall 2007, Vol. 30, No. 1. Draft version available at http://www.levyinstitute.org/publications/?docid=911
  2. Wynne Godley and Bob Rowthorn, Appendix; The Dynamics Of Public Sector Deficit And Debt, in J. Michie and J. Grieve Smith (eds), Unemployment in Europe (London: Academic Press), pp. 199-206.
  3. Lance Taylor, A Foxy Hedgehog: Wynne Godley And Macroeconomic ModellingCamb. J. Econ. (2008) 32 (4):639-663.

Updated 2 August 2012 8am GMT [minor corrections]

More On Wynne Godley’s Methodology

Matias Vernengo has a post on Stock-Flow Consistent Macroeconomics: Stock-Flow With Consistent Accounting (SFCA) Models.

He has a nice way of giving a short description of pricing in the G&L models:

In my view, the stock-flow and the demand driven (and I should say, the fact that price dynamics is orthogonal to the income flow determination structure) is the essential characteristic of this approach.

Also, Simon Wren-Lewis (from Oxford) has a new blog post on the sectoral balances approach – Sector Financial Balances As A Diagnostic Check, where he mentions Martin Wolf’s recent post on Wynne Godley’s approach. He (Wren-Lewis) has been admitting recently that DSGE models are not useful.

In the comments section Simon Wren-Lewis has this to say:

Martin Wolf sent me the following comment, which I am sure others will also find interesting:

“I used sectoral financial balances before the crisis, following Wynne. I argued that what was going on in the US external and household sectors were evidently unsustainable. This allowed me to argue that when the latter’s deficits were eliminated, there would be a recession and a huge fiscal deficit. What I had not expected was that the turnaround in the household sector would trigger a meltdown of the financial system.

“This makes it clear that one has to link the flow sectoral balances to the balance sheets in the economy. In this case, my mistake was not looking closely enough at the balance sheet of the financial sector. Good macroeconomic analysis has to examine the flows and stock meticulously and seek to assess whether the behaviour we see is sustainable. The assumption that private agents cannot make huge mistakes about the sustainability of what they are doing is, in my view, the biggest mistake in macroeconomics.”

Back to DSGE models. I think they are totally useless. I like this quote by Francis Cripps from an article in The Guardian from 27 Feb 1979: Economists With A Mission: