For example, many of the food categories excluded in the standard measure of core inflation, such as food away from home (restaurants), are not highly volatile and so likely should remain in an optimal core inflation measure.
On the other hand, some items that are not excluded from the U.S. core measures, such as airline fares, tobacco, and apparel, are extremely volatile and thus are unlikely to be included in an optimal core inflation measure. The Bank of Canada, for example, uses a more targeted approach to its core inflation indicator, the CPIX.