November 13, 1997 As a guide for the conduct of monetary policy, most central banks make use of a trend inflation index similar to that employed by the Bank of Canada: the CPI excluding food, energy, and the effect of indirect taxes. In addition to their basic reference index, some central banks regularly publish statistical measures of the trend rate of inflation. The method used for producing these measures is, for the most part, based on the hypothesis that extreme price fluctuations generally reflect temporary shocks to the inflation rate, rather than its underlying trend. In this paper, the author offers a broad survey of studies on the measurement of trend inflation that have been published by the Bank of Canada and presents the results of the most recent work on the subject. Particular attention is paid to two statistical measures that the Bank follows more closely than other measures; namely, the CPIX, a price index that excludes eight of the most volatile CPI components, and CPIW, a measure that retains all the components of the overall index but gives a lower weighting to the most volatile.
In this paper, the author calculates new measures of the trend inflation rate using changes in the components of total CPI; the hypothesis is that extreme fluctuations in certain prices reflect temporary supply shocks rather than any basic price trend.