Economists still lack a proper understanding of business cycles

THE aftermath of the 2007-08 financial crisis ought to have been a moment of triumph for economics. Lessons learned from the 1930s prevented the collapse of global finance and trade, and resulted in a downturn far shorter and less severe than the Depression. But even as the policy remedies were helpful, the crisis exposed the economic profession’s continued ignorance of the business cycle. That is bad news not just for the discipline, but for everyone.

The aim of those studying the macroeconomy has always been to understand the economy’s wobbles, and to work out when governments should intervene. That is not easy. Downturns come often enough to be a serious irritant, but not often enough to give economists sufficient data for rigorous statistical analysis. It is hard to distinguish between short-run swings and structural economic changes resulting from demography or technology. Most classical economists were sceptical of the idea that the macroeconomy needed much oversight at all.