Cyclical contractions are often referred to as inventory cycles, in part because movements in inventories can amplify cyclical fluctuations in output. An unanticipated slowing in demand generally leads to an unintended buildup of inventories: only with a lag do firms adjust production and their actual holding of inventories relative to the desired level.
A monetary authority with the primary objective of price stability has to distinguish between temporary price shocks and persistent shocks to the rate of inflation. A measure of underlying inflation, therefore, has an important role to play as a guideline for monetary policy.
