A Positive Theory of Monetary Policy and Robust Control

Abstract

This paper applies the robust control approach to a simple positive theory of monetary policy, when the central bank's model of the economy is subject to misspecifications.It is shown that a central bank should react more aggressively to supply shocks when the model misspecifications grow larger.Moreover, the model misspecifications aggravate the inflation bias and a trade-off between output stabilisation and inflation worsens when the uncertainty surrounding the central bank's model increases.This implies that the larger the model misspecifications are, the more inflation-averse the central bank should be. Key words: risk-sensitivity, robust control theory, monetary policy, Brainard conservatism, model uncertainty JEL classification numbers: E58