Dealing with forward-looking expectations and policy rules in quantifying the channels of transmission of monetary policy

The issue of appraising the transmission process through which monetary policy affects the economy is receiving wider and increasing attention. In Europe, much of the interest in the effects of monetary policy is arguably a reflection of the introduction of the single currency: to the extent that transmission mechanism differ significantly across euro area countries, heterogenous responses of economic activity and prices to the policy instrument should be expected, an occurrence whose policy implications are of major relevance. To gain some insight into the likely causes of those differences recent studies have attempted to identify and assess separately the channels of transmission of monetary policy. This paper proposes a simple methodology to quantify separately the different parts of the overall impulse response that are transmitted through the various mechanisms at play in a model of the economy. It is shown that, under the maintained assumption of linearity, the decomposition of the effects of monetary policy into a number of channels delivered by our approach is exact (i.e., it leaves no unexplained residual). This conclusion holds regardless of the nature of the expectation formation mechanism and the way in which policy decisions are modelled. The features of the proposed approach are illustrated with an empirical application, using a model that features two distinct transmission channels and assumes rational expectations and a monetary policy reaction rule. We show that our approach produces an exact decomposition of the effects of a monetary policy shock. Moreover, and perhaps more interestingly, our approach gives a deeper insight than do standard impulse responses into the specific features of the model that are most relevant in shaping its observed reaction to the shock.