The joint dynamics of inflation, unemployment and interest rate in the United States since 1980

In this paper, by using a combination of long-run and short-run restrictions, we identify a small structural VECM which includes inflation, unemployment and the federal funds rate and study the dynamic interactions at different frequencies among these variables. Our results show that: (a) in accordance with the traditional view of economic fluctuations, aggregate demand shocks and monetary policy shocks push inflation and unemployment in opposite directions in the short run; (b) the permanent supply shock explains the long-run movement of inflation and unemployment. These conclusions are at odds with the prediction of natural-rate models but are consistent with the idea of a propagation mechanism which links productivity shocks to inflation and unemployment at medium and low frequencies. Thus, with respect to some recent studies (e.g. Beyer and Farmer, ECB Working Paper 121, 2002, and Ireland, J Monet Econ 44:279291, 1999), we offer a different interpretation of the low-frequency comovements between inflation and unemployment characterizing the US economy in the last decades.