Consumer Price Index / CPI

Sources
Dernière mise à jour le : 16/02/2016

Présentation de l'opération

Organisme producteur :

Insee. Direction des statistiques démographiques et sociales (DSDS)

Type d'opération :

Prices Index

Objectifs :

The consumer price index (CPI) is the instrument used to measure inflation. It allows the estimation of the average variation between two given periods in the prices of products consumed by households.
It is based on the observation of a fixed basket of goods updated every year. Each product has a weight in the overall index that is proportional to its weight in household expenditure.
It is published each month in the Official Journal of French Republic. The price index excluding tobacco is used to index link many private contracts, alimony, annuities and also the minimum wage (SMIC).
The index used for the SMIC is that of the "Households that belong to the lowest equivalized disposable income quintile" (Decree n° 2013-123, February 7th of 2013).


Champ de l'opération

Champ géographique :


National
The French overseas departments (DOM), except Mayotte, have been  included in the CPI since the 1998 base.

Caractéristiques techniques

Unité statistique enquêtée :

Retail outlet

Périodicité de l'opération :

Monthly

Période et mode de collecte :

Data is collected throughout the month by an investigator. Reports are monthly.
Tablet computers are used for data entry.

Historique :


The first generation of indices dates back to 1914. Over time, the IPC's coverage has broadened, both on a geographical level and in terms of the population represented and consumption covered.
The CPI 2015 base constitutes the 8th generation of indices used. It was brought into service in January 2016.

Plan de sondage :

The sampling plan is stratified according to three types of criteria:
- Geographical criterion: surveys are carried out in 99 conurbations of over 2,000 inhabitants situated throughout metropolitan France and of any size and 10 conurbations in four Overseas Departments (Guadeloupe, Martinique, Guyane, Réunion).
- Type of product: a sample of just over 1,100 product families, called "varieties" is defined in order to take account of the heterogeneity of products within items. The variety is the basic level for tracking products and calculation of the index. The list of varieties remains confidential and the CPI is not disseminated at this level.
- Type of retail outlet: a sample of 30,000 retail outlets, stratified according to the form of sale, has been created in order to represent the diversity of products and purchasing methods used by consumers, and to take account of the price variations, which are differentiated according to the forms of sale.
By cross-referencing these different criteria, just over 200,000 series (specific products in a given retail outlet) can be monitored. To these figures can be added approximately 190,000 "pricing"-type series collected in a centralised manner.
The sample is updated annually in order to take account of consumer behaviour trends and, especially, in order to introduce new products.
The revisions concern the list and content of varieties and the distribution per form of sale, or even per conurbation.
The CPI is an annually chain-linked Laspeyres index.
In addition to the composition of the sample, the weightings used to aggregate the elementary indices (cross-referencing of varieties x conurbation in general) are also updated each year.
These weightings represent the proportion of expenditure associated with the aggregate concerned within all consumer expenditure of households covered by the CPI.
The majority of them are obtained from the annual evaluations of household consumer expenditure carried out by the National Accounts.
Special operations are carried out for  seasonal varieties, and pricing varieties, and in order to determine the trends of "pure" price evolutions, at a constant quality, when a product that disappears is replaced by another during the year.
Promotions and sales offered to all consumers are taken into consideration.

Autres spécifications :

The CPI covers all market goods and services consumed throughout the country by resident and non-resident (e.g. tourists) households. Its theoretical scope is defined as the actual final monetary consumption of households.
Following major extensions carried out primarily in services, the CPI's rate of coverage was  97% in 2016 (2015 base).
The main shortcomings concerning coverage still relate to private hospital services and life insurance.