I am puzzled why the remarkably similar housing bubbles that emerged in more than two dozen countries between 2001 and 2006 are not seen to have a common cause. The dramatic fall in real long-term interest rates statistically explains, and is the most likely major cause of, real estate capitalisation rates (rent as a percentage of a property’s value) that declined and converged across the globe. By 2006, long-term interest rates for all developed and main developing economies declined to single digits, I believe for the first time ever.

Doubtless each individual housing bubble has its own idiosyncratic characteristics and some point to Federal Reserve monetary policy complicity in the US bubble. But the US bubble was close to median world experience and the evidence that monetary policy added to the bubble is statistically very fragile. Paul De Grauwe, writing in the Financial Times’ Economists’ Forum, depends on John Taylor’s counterfactual model simulations to conclude that the low funds rate was the source of the US housing bubble. Mr Taylor (with whom I rarely disagree) and others derive their simulations from model structures that have been consistently unable to anticipate the onset of recessions or financial crises. Counterfactuals from such flawed structures cannot form the basis for policy.