They should publish their own inflation index and compare it with the "official" numbers published by the governemnt
For example, let’s say you have a fixed rate mortgage on the home you own and live in. If house prices skyrocket because supply is restricted, that inflation doesn’t affect you. Or let’s say you spend $200 per month on food out of a total budget of $4000. If food prices go up uniformly 20%, but nothing else changes for all the other stuff you buy (ie, you’re paying $40 more per month than you were before), you’re effective inflation rate is 1%.