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Consumer price index (CPI). By expenditure groups. Methodology

    Definition of concepts

    Consumer price index (CPI)
    Measurement of the evolution of the level of the prices of consumer goods and services acquired by households, in relation to the price that the same goods and services had in 2021 (base 2021 = 100).

    Methodological aspects

    The Consumer Price Index (CPI) measures the change over time in the prices of consumer goods and services purchased by people living in households in Spain. Consumer expenditure means the monetary flow paid for the acquisition of goods and services classified as such in a nomenclature expressly drawn up by the INE. Expenditure which could be classified as investment, such as buying a house or flat, is excluded.

    The CPI is calculated based on the Laspeyres formula, which is a weighted arithmetic mean of the price indexes of the various consumer items covered. Since January 2021 a new consumer price index system, CPI base 2021, has been used which is designed to provide more representative coverage and greater precision in measuring change in this indicator by expanding the sample of towns, increasing the number of prices gathered, changes in the make-up of the basket of consumer articles and more updated weightings.

    The base 2021 sample is made up of 177 towns, and the total number of prices collected are 210.000, which means that the monthly calculation of the CPI is carried out using 177 towns.

    The most noticeable changes in the configuration of the base 2021 basket of goods are the incorporation of face masks and subscriptions to online newspapers.

    The number of items that make up the basket of goods is 462.

    The weighting structure for base 2021 has been drawn up based on the Survey of Family Budgets (SFB). Furthermore, information from other sources has been used to determine the final structure:

    • change in private consumer spending from National Accounting
    • change in CPI prices
    • other sources about supply in the various sectors

    Consumer expenditure has been classified in accordance with a nomenclature drawn up by the INE based on the ECOICOP (European Classification Of Individual Consumption by Purpose), a harmonized European Union nomenclature. Consumer items that are going to remain on the market and are regularly consumed by the public are chosen.

    Unavailable information is represented using the symbol ":". When the value is lower than that of the minimum unit to be able to estimate the statistical operation or if it effects statistical confidentiality, the symbol used is "..".