This takes into account the fact that monetary policy affects the price level only with variable, usually long and unpredictable time lags. It is not able to control all short-term movements in the price level.
Furthermore, the historical experience of central banks in Europe and beyond demonstrates that it is important for the success of monetary policy to carry out a thorough analysis of monetary aggregates and the information they contain. The Governing Council of the ECB has announced a quantitative reference value for the annual growth of the broad monetary aggregate M3.