Macroeconomic foundations made of sand

28 februari, 2015 kl. 15:57 | Publicerat i Economics | Kommentarer inaktiverade för Macroeconomic foundations made of sand

Olivier Blanchard, the IMF’s chief economist, recently wrote:

”We in the field did think of the economy as roughly linear, constantly subject to different shocks, constantly fluctuating, but naturally returning to its steady state over time. Instead of talking about fluctuations, we increasingly used the term “business cycle.” Even when we later developed techniques to deal with nonlinearities, this generally benign view of fluctuations remained dominant.”

o-OSTRICH-IN-THE-SAND-facebookThe models that macroeconomic practitioners developed reflected this essentially linear view. Blanchard went on to observe that although macroeconomists did not ignore the possibility of extreme tail risk events, they regarded them as a thing of the past in developed countries … If you get the policy settings right, linear models will work.

Except that they won’t. And that is because these models are not realistic views of how the economy actually works. Representative agents aren’t actually representative of anyone. Rational expectations are driven as much by emotion as logic …

Leaving banks out of economic models, or – worse – modelling their money-creating function incorrectly, made it impossible for mainstream economists to understand the significance of the build-up of credit that led to the financial crisis. The warnings came principally from people outside mainstream economics, particularly the followers of Hyman Minsky. After the crisis, Minsky’s “financial instability hypothesis”, long consigned to a dusty shelf in a dark cupboard, suddenly became hot news. Unsurprisingly, since we had just lived through something that looked very like a ”Minsky moment”.

Clearly, the exclusion of the financial industry from models of the macroeconomy was a major omission. Equally clearly, the fact that most macroeconomists did not, and to a large extent still do not, understand the mechanisms by which money is created and circulated in the modern monetary economy, is a big, big problem. Central banks are now “adding” the financial sector to existing DSGE models: but this does not begin to address the essential non-linearity of a monetary economy whose heart is a financial system that is not occasionally but NORMALLY far from equilibrium. Until macroeconomists understand this, their models will remain inadequate …

Some of the most influential people in macroeconomics have spent their lives developing theories and models that have been shown to be at best inadequate and at worst dangerously wrong. Olivier Blanchard’s call for policymakers to set policy in such a way that linear models will still work should be seen for what it is – the desperate cry of an aging economist who discovers that the foundations upon which he has built his career are made of sand. He is far from alone.

Frances Coppola

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