For the harmonised indices to be considered comparable, any differences across Member States at all levels of detail shall only reflect differences in price changes or expenditure patterns.
Chun go measfar na hinnéacsanna comhchuibhithe a bheith inchomparáide, ní léireoidh aon difríochtaí idir Ballstáit ar gach leibhéal mionsonraí ach na difríochtaí in athruithe ar phraghsanna nó i bpatrúin chaiteachais.