Changing effects of monetary policy in the US-evidence from a time-varying coefficient VAR

We estimate a time-varying coefficient VAR model for the US economy to analyse (i) if the effect of monetary policy on output has been changing systematically over time, and (ii) if monetary policy has asymmetric effects over the business cycle. We find that the impact of monetary policy shocks has been gradually declining over the sample period (1962 to 2002), as some theories of the monetary transmission mechanism imply. In addition, our results indicate that the effects of monetary policy are greater in a recession than in a boom.