Targeting Inflation Over the Short, Medium and Long Term

An inflation targeting central bank aims to stabilize the rate of inflation. But which 'inflation' should this be? Quarterly, annual, biennial? We analyze the effects on optimal monetary policy of increasing the period over which the inflation rate is defined. When inflation stabilization is the sole objective of the central bank, more aggressive monetary policy results; but when output stabilization is also a concern the result is a more cautious conduct of monetary policy and less variability in output. Thus, there is an observational equivalence between increasing the period over which inflation is measured and increasing the weight on output stabilization in the central bank's objective function. The analogy between inflation targeting with an infinite-period target and price level targeting is also examined