Definition: Consumer price index
Purchasing power parities
A monthly or quarterly price index compiled and published by an official statistical agency that measures the changes in the prices of consumption goods and services acquired or used by households. Its exact definition may vary from country to country. In Eurostat and OECD comparisons, CPI (International comparison programme) sub-indices are used as "temporal adjustment factors" to adjust the average survey prices collected for consumer products to annual average prices. They are also used in to extrapolate basic heading PPPs (Purchasing power parities) for a survey year to non-survey years as required by the "rolling survey approach".
Eurostat, Organization for Economic Cooperation and Development (OECD), "Eurostat-OECD Methodological Manual on Purchasing Power Parities", Publications Office of the European Union, Luxembourg, 2012