It could easily be 18 months or longer from when policy interest rates are raised to when it fully works through and moderates the inflation rate. In this world of long lags, credible inflation targeting seems a useful mechanism to shorten the outside lag and perhaps moderate the magnitude of the interest rate changes required to achieve a particular outcome.
If there is no doubt that the authorities are committed to the inflation target and will in the end prevail, economic agents are likely to set their prices and wages at levels readily reconcilable with the inflation target, and are likely to view deviations from the target as temporary.