Why Real Business Cycle models can’t be taken seriously
from Lars Syll
They try to explain business cycles solely as problems of information, such as asymmetries and imperfections in the information agents have. Those assumptions are just as arbitrary as the institutional rigidities and inertia they find objectionable in other theories of business fluctuations … I try to point out how incapable the new equilibrium business cycles models are of explaining the most obvious observed facts of cyclical fluctuations … I don’t think that models so far from realistic description should be taken seriously as a guide to policy … I don’t think that there is a way to write down any model which at one hand respects the possible diversity of agents in taste, circumstances, and so on, and at the other hand also grounds behavior rigorously in utility maximization and which has any substantive content to it.
Real Business Cycle theory basically says that economic cycles are caused by technology-induced changes in productivity. It says that employment goes up or down because people choose to work more when productivity is high and less when it’s low. This is of course nothing but pure nonsense — and how on earth those guys that promoted this theory (Thomas Sargent et consortes) could be awarded The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel is really beyond comprehension.
In yours truly’s History of Economic Theories (4th ed, 2007, p. 405) it was concluded that
the problem is that it has turned out to be very difficult to empirically verify the theory’s view on economic fluctuations as being effects of rational actors’ optimal intertemporal choices … Empirical studies have not been able to corroborate the assumption of the sensitivity of labour supply to changes in intertemporal relative prices. Most studies rather points to expected changes in real wages having only rather little influence on the supply of labour.
Rigorous models lacking relevance is not to be taken seriously. Or as Keynes had it — It is better to be vaguely right than precisely wrong …