Unter all dem Beschuss auf die VWL im allgemeinen, haben die Geschosse auf die Makroökonomie den größten Bums. Abgefeuert werden die nicht nur von Akademikern, Journalisten oder Studentinnen auf kleinen Blogs, sondern zum Beispiel auch von Andres Haldane von der britischen Zentralbank. Bei der Bank of England ist er zuständig für Finanzstabilität. Dass Leute in seiner Position den gängigen Makromodellen kritisch gegenüberstehen, scheint mir selten vorzukommen. Im Folgenden aus einem Interview mit Olaf Storbeck ein paar zentrale Punkte seine Kritik an der gängigen Makroökonomie und Ansätze, wie die Modelle verbessert werden könnten, zum Beispiel durch heterogene Agenten.
What are the issues of contemporary macro economics?
With the benefit of hindsight, we built an edifice, a set of models, that were quite peculiar in the assumptions they made . For example, we drifted away from the notion of having a multiplicity of equilibria. We also forgot that we could even get stuck in the wrong equilibrium, which is one way of making sense of where we are today. We drifted away from the notion that systems could become dynamically unstable when stretched or stressed too much. It is hard to think of a system outside of economics, whether from the natural world or from social sciences, that doesn’t have a multiplicity of equilibria and doesn’t behave peculiarly when stretched or stressed and can which be destabilising. However, in modern macro, the notion of equilibrium was a singular stationary, stabilising concept.
Is it possible to make sense of such a system at all?
Yes, to a certain degree. But economists have to recognise two things which are not currently embedded within the workhorse framework. The first is heterogenitey of the people in the system. The second important insight is that what people do depends a lot on what they think.
Expectations are already built into macro models, aren’t they?
That’s right, but not in a satisfying way. Rational expectations theory says that what people think depends a lot on what’s happening. Basically, expectations are seen to mirror fundamentals. For me, it’s sometimes the other way round. Fundamentals are driven by expectations. Happiness, sadness or panic are real emotions. Even if they are based on nothing in particular, they will drive behaviours and outcomes.
Hence contemporary macro has been rendered useless?
No, I would not want to dump all that has been done. There is still a usefulness in the existing workhorse models, suitably augmented with some of the things I’ve discussed. Those models need a more imaginative introduction of expectations, a more imaginative introduction of heterogenous agents, and a more imaginative introduction of financial frictions. That said, it would be a real mistake to confine ourselves to that one class of model. We need a more plural approach to the way we think things through. So I would like to see much greater intellectual investment in different frameworks.
There are lots of non-conventional avenues which have historically been niche and need to become more central. Agent based modelling is just one example. This approach obliges you to take very seriously heterogeneity of agents, interactions between agents. Another important area is to increase the importance placed on studying the history of economic thought.