Monetary indicators and policy rules in the P-star model

There is a broad consensus among economists that, in the long run, inflation is a monetary phenomenon. However, monetary policy is often analysed using models that have no causal role for monetary aggregates in the propagation of inflationary processes. Moreover, impulses from monetary policy actions are transmitted to inflation through the output gap alone. This paper analyses monetary indicators and monetary policy rules within the framework of a small monetary model, the P-star model. In this model monetary aggregates play an active role in the transmission mechanism of monetary policy actions. Interest rate impulses affect inflation through two channels, the output gap and the liquidity gap. Section 2 of the paper analyses monetary indicators of inflation. Using a long-run money demand function, three monetary indicators are discussed: the monetary overhang, the price gap, and the nominal money gap. The price gap is a comprehensive indicator of inflationary pressure, combining information from the aggregate goods market (output gap) and the money market (liquidity gap). Some implications of using the price gap in Phillipstype equations for the dynamics of inflation are discussed as well. Section 3 analyses the role of the price gap in the monetary transmission process more closely. The P-Star model and a New-Keynesian-Taylor-type model are compared with respect to their stability properties, implied sacrifice ratios and the efficiency of interest rate policy in stabilising inflation and output fluctuations. Section 4 explores a range of monetary policy rules within the P-star model...