Comment by throw0101d

> The physical size of charmin changed during the pandemic.

This is generlly taken into account. From StatCan, who publishes Canada's CPI numbers:

> 7.10 Quantity adjustment entails accounting for changes in the quantity (e.g. package size, number of tissue ply, etc.) of observed POs. This is another implicit method of quality adjustment because it is assumed that the quality per standardized unit is the same over time.

> 7.11 Quantity adjustment is the default treatment for nearly all of the POs in the food major aggregate as well as some of the products in the household operations, and personal care supplies and equipment aggregates.

* https://www150.statcan.gc.ca/n1/pub/62-553-x/2023001/chap-7-...

* https://www150.statcan.gc.ca/n1/en/catalogue/62-553-X