The HICPs are economic indicators constructed to measure the changes over time in the prices of consumer goods and services acquired by households. The HICPs give comparable measures of inflation in the euro-zone, the EU, the European Economic Area and for other countries including accession and candidate countries. They are calculated according to a harmonised approach and a single set of definitions. They provide the official measure of consumer price inflation in the euro-zone for the purposes of monetary policy in the euro area and assessing inflation convergence as required under the Maastricht criteria.
HICP data, including backdata, is revisable under the terms set in Commission Regulation (EC) No 1921/2001. When updated (see release calendar), the database overwrites existing data with the revised data and those changes will only be flagged for a short period, generally until the next update.
If you are dealing with indexation you should bear in mind that HICP can be revised at any point in time. Revisions may also affect backdata. To trace revisions, please refer to the monthly HICP publication 'Data in Focus' (pdf).