Purchasing Power Parities (PPP) arose over the need to homogeneously compare the economic capacity of nations.

In this context, the PPP are the exchange rates that are equal to the purchasing power of foreign currencies used in countries that participate in the comparison. Comparison of purchasing power is carried out by eliminating the differences in price levels of the nations analysed.

The first work on PPP was carried out in the 1950s to study the price levels of GDP of the United States with that of the main European economies. The number of nations participating in the comparison has grown progressively and finally it was necessary to group the countries by region. International coordination of all this activity is the responsibility of different international organisations: Eurostat, OECD and the World Bank.

The work by Spain, together with that of the other 30 European countries is coordinated by Eurostat.