Donnerstag, 9. Oktober 2014

Bonmot von Stiglitz

In einem aktuellen Arbeitspapier schreibt er über die Defizite von mikrofundierten Makromodellen mit rationalen Erwartungen und warum es kein Wunder ist, dass diese die jüngsten Krise nicht erklären - geschweige denn prognostizieren konnten.
"Part of the reason for the failure of these [microfounded rational-expectations macro] models was their reliance on the concept of the fully rational representative agent with rational expectations—the notion that the economy could be well described as if it consisted of a group of identical such individuals.  Such models couldn't embrace information asymmetries:  with a representative agent, these could only arise if the individual suffered from acute schizophrenia, which would in turn be hard to reconcile with their assumptions of all-knowing rationality.  

Moreover it is hard to have a robust financial sector in representative agent models:  who is lending to whom?  Since all risk is borne by the same (representative) agent, financial structure can’t matter.  Not surprisingly, banks then play no role.   With the financial sector at the center of this, and many other crises, it is no wonder that these models had little to say—either before or after the crisis." 

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