Mittwoch, 23. September 2009

Colander on DSGE-Models

David Colander beschreibt in seinem Bericht an US-Kongress, was er für die wichtigste Fehlentwicklung der modernen Makroökonomie hält, nämlich, dass die seit den 1980ern entwickelten Modelle des allgemeinen Gleichgewichts (Dynamik Stochastic General Equilibrium (DSGE) Models) nicht mehr als ein Instrument zum Verstehen der Welt, sondern als DAS Abbild der Welt betrachtet wurden und die Entwicklung von andere Aspekte beleuchtenden Modellen weitgehend eingestellt wurde.

Einige Zitate:
" In my view the problem is not the models; the problem is the way economic models are used."
"It was a tragedy for the science of economics because it led economists away from developing a wide variety of models that would creatively explore the extraordinarily difficult questions that the complexity of the economy raised, questions for which new analytic and computational technology opened up new avenues of investigation. Instead, the economics profession spent much of its time dotting i’s and crossing t’s on what was called a Walrasian general equilibrium model which was more analytically tractable."
"Had the DSGE model been seen as an aid to common sense, it could have been a useful model. When early versions of this model first developed back in the early 1980s, it served the useful purpose of getting some intertemporal issues straight that earlier macroeconomic models had screwed up. But then, for a variety of sociological reasons that I don’t have time to go into here, a majority of macroeconomists started believing that the DSGE model was useful not just as an aid to our understanding, but as the model of the macroeconomy. That doesn’t say much for the common sense of rocket economists. As the DSGE model became dominant, important research on broader non-linear dynamic models of the economy that would have been more helpful in understanding how an economy would be likely to crash, and what government might do when faced with a crash, was not done."
" Unfortunately, the warning labels on the models that should have been there in bold print—these models are based on assumptions that do not fit the real world, and thus the models should not be relied on too heavily—were not there."
Die Auswahl an Zitaten trifft's meiner Meinung nach ziemlich genau.

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