Schnurr writes that CPI-common: “which the central bank says is the best gauge of the economy’s underperformance, held at 1.3 per cent”. The Bank of Canada has shown a preference for CPI-common as its core inflation measure over the other two measures that now make up its operational guide, more it would seem, because for a long time it showed lower inflation rates than any other measure than due to any inherent advantages. However a core inflation measure is not equivalent to a gauge of the economy’s underperformance, and even the Bank of Canada never suggested it was. In fact its technical box on “New measures of core inflation” claims that the new core measures are to be preferred to CPIX because of an alleged stronger “peak correlation between the output gap at time t and the core inflation measure x quarters later [t + x],” where x is between two and seven.