LARS P. SYLL

Economic forecasting — why it matters and why it is so often wrong

As Oskar Morgenstern noted in his 1928 classic Wirtschaftsprognose: Eine Untersuchung ihrer Voraussetzungen und Möglichkeiten, economic predictions and forecasts amount to little more than intelligent guessing.

Making forecasts and predictions obviously isn’t a trivial or costless activity, so why then go on with it?

The problems that economists encounter when trying to predict the future really underline how important it is for social sciences to incorporate Keynes’s far-reaching and incisive analysis of induction and evidential weight in his seminal A Treatise on Probability (1921).

According to Keynes, we live in a world permeated by unmeasurable uncertainty – not quantifiable stochastic risk – which often forces us to make decisions based on anything but ‘rational expectations.’ Keynes rather thinks that we base our expectations on the confidence or ‘weight’ we put on different events and alternatives. To Keynes, ​expectations are a question of weighing probabilities by ‘degrees of belief,’ beliefs that often have preciously little to do with the kind of stochastic probabilistic calculations made by the rational agents as modelled by ‘modern’ social sciences. And often we “simply do not know.”

How strange that social scientists and mainstream economists, as a rule, do not even touch upon these aspects of scientific methodology that seem to be so fundamental and important for anyone trying to understand how we learn and orient ourselves in an uncertain world. An educated guess on why this is a fact would be that Keynes’s concepts are not possible to squeeze into a single calculable numerical ‘probability.’ In the quest for measurable quantities, one puts a blind eye to qualities and looks the other way.

So why do companies, governments, and central banks, continue with this more or less expensive, but obviously worthless, activity?

A part of the answer concerns ideology and apologetics. Forecasting is a non-negligible part of the labour market for (mainstream) economists, and so, of course, those in the business do not want to admit that they are occupied with worthless things (not to mention how hard it would be to sell the product with that kind of frank truthfulness). Governments, the finance sector and (central) banks also want to give the impression to customers and voters that they, so to say, have the situation under control (telling people that next year x will be 3.048 % makes wonders in that respect). Why else would anyone want to pay them or vote for them? These are sure not glamorous aspects of economics as a science, but as a scientist, it would be unforgivably dishonest to pretend that economics doesn’t also perform an ideological function in society.

Hyman Minsky and the IS-LM obfuscation

As a young research stipendiate in the U.S. yours truly had the pleasure and privilege of having Hyman Minsky as a teacher. He was a great inspiration at the time. He still is.

The concepts which it is usual to ignore or deemphasize in interpreting Keynes — the cyclical perspective, the relations between investment and finance, and uncertainty, are the keys to an understanding of the full significance of his contribution …

The glib assumption made by Professor Hicks in his exposition of Keynes’s contribution that there is a simple, negatively sloped function, reflecting the productivity of increments to the stock of capital, that relates investment to the interest rate is a caricature of Keynes’s theory of investment … which relates the pace of investment not only to prospective yields but also to ongoing financial behavior …

The conclusion to our argument is that the missing step in the standard Keynesian theory was the explicit consideration of capitalist finance within a cyclical and speculative context. Once capitalist​ finance is introduced and the development of cash flows … during the various states of the economy is explicitly examined, then the full power of the revolutionary insights and the alternative frame of analysis that Keynes developed becomes evident …

The greatness of The General Theory was that Keynes visualized [the imperfections of the monetary-financial system] as systematic rather than accidental or perhaps incidental attributes of capitalism … Only a theory that was explicitly cyclical and overtly financial was capable of being useful …

If we are to believe Minsky — and I certainly think we should — then when people like Paul Krugman and other ‘New Keynesian’ critics of MMT and Post-Keynesian economics think of themselves as defending “the whole enterprise of Keynes/Hicks macroeconomic theory,” they are simply wrong since there is no such thing as a Keynes-Hicks macroeconomic theory!

There is nothing in the post-General Theory writings of Keynes that suggests that he considered Hicks’s IS-LM anywhere near a faithful rendering of his thoughts. In Keynes’s canonical statement of the essence of his theory in the 1937 QJE article there is nothing to even suggest that Keynes would have thought the existence of a Keynes-Hicks-IS-LM-theory anything but pure nonsense. So, of course,​ there can’t be any “vindication for the whole enterprise of Keynes/Hicks macroeconomic theory” — simply because “Keynes/Hicks” never existed.

To be fair to Hicks, we  shouldn’t forget that he returned to his IS-LM analysis in an article in 1980 — in Journal of Post Keynesian Economics — and self-critically wrote:

The only way in which IS-LM analysis usefully survives — as anything more than a classroom gadget, to be superseded, later on, by something better — is in application to a particular kind of causal analysis, where the use of equilibrium methods, even a drastic use of equilibrium methods, is not inappropriate. I have deliberately interpreted the equilibrium concept, to be used in such analysis, in a very stringent manner (some would say a pedantic manner) not because I want to tell the applied economist, who uses such methods, that he is in fact committing himself to anything which must appear to him to be so ridiculous …

When one turns to questions of policy, looking toward the future instead of the past, the use of equilibrium methods is still more suspect … It may be hoped that, after the change in policy, the economy will somehow, at some time in the future, settle into what may be regarded, in the same sense, as a new equilibrium; but there must necessarily be a stage before that equilibrium is reached …

We now know that it is not enough to think of the rate of interest as the single link between the financial and industrial sectors of the economy; for that really implies that a borrower can borrow as much as he likes at the rate of interest charged, no attention being paid to the security offered. As soon as one attends to questions of security, and to the financial intermediation that arises out of them, it becomes apparent that the dichotomy between the two curves of the IS-LM diagram must not be pressed too hard.

In his 1937 paper, Hicks actually elaborates on four different models (where Hicks uses I to denote Total Income and Ix to denote Investment):

1) “Classical”: M = kI   Ix = C(i)   Ix = S(i,I)

2) Keynes’ “special” theory: M = L(i)   Ix = C(i)    I = S(I)

3) Keynes’ “general” theory: M = L(I, i)   Ix = C(i)   I = S(I)

4) The “generalized general” theory: M = L(I, i)   Ix =C(I, i)  Ix = S(I, i)

It is obvious from the way Krugman and other ‘New Keynesians’ draw their IS-LM curves that they are thinking in terms of model number 4 — and that is not even by Hicks considered a Keynes model! It is basically a loanable funds model, that belongs in the neoclassical camp and which you find reproduced in most mainstream textbooks.

Hicksian IS-LM? Maybe. Keynes? No way!

Systembrus

En vanlig missuppfattning när det gäller oönskad variabilitet i bedömningar är att det inte spelar någon roll eftersom slumpfel tar ut varandra. Det stämmer att positiva och negativa fel i en bedömning av samma fall mer eller mindre tar ut varandra och vi kommer att diskutera mer i detalj hur denna omständighet kan utnyttjas för att minska bruset. Men brusiga system gör inte flera bedömningar av samma fall. De gör brusiga bedömningar av olika fall. Om en försäkring har för hög premie och en annan för låg kan prissättningen se korrekt ut “i genomsnitt”, men försäkringsbolaget har då begått två dyrbara misstag. Om två brottslingar som båda borde dömas till fem års fängelse får domar på tre respektive sju år kan inte någon “genomsnittlig” rättvisa sägas ha skipats. I brusiga system tar felen inte ut varandra. De läggs pa hög.

Victoria Chick (1936-2023) In Memoriam

Sad news has reached us today. One of the leading Post Keynesian economists, Victoria Chick, passed away yesterday at the age of 86.

R.I.P.