Building maintenance and improvement work indices (Indices des prix des travaux d’entretien-amélioration des bâtiments – IPEA in French) are calculated quarterly from the observation of the prices charged by a sample of companies and craftsmen (artisanals) to final customers, for works carried out in existing buildings in France and necessarily involving the laying and the supply of materials. These prices exclude taxes, discounts and subcontract markets.

NAF rév.2 / CPF rév 2.1

The statistical unit investigated is the legal unit of a company that produces the goods of the industrial activity in question.

The building maintenance and improvement work index (IPEA) is a quarterly index measuring evolution of price excluding taxes charged by construction enterprises for their maintenance and improvement of existing buildings. In 2010 basis, these indices cover only housings. In 2015 basis, they also cover non residential buildings. Accordingly, the perimeter of IPEA indices for «all work» change. The IPEA indices are also disseminated by classes of the nomenclature NAF Rev 2/CPF Rev 2.1, as defined below: 
- 4321 Electrical installation work;
- 4322 Sanitary plumbing, heating and thermoregulation for heating plants;
- 4329 Other installation works;
- 4331 Plastering works;
- 4332 Metallic carpentry, lock-smithery;
- 4333 Wall covering, supple floor covering;
- 4334 Painting,and glazing work;
- 4339 Other finishing works;
- 4391 Roofing, zinc works;
- 4399 Miscellaneous special-trade construction works.

However, within the NAF class 4321, the subclass "4321B Electrical installation works on the highway" is not tracked by the IPEA indices. The subclasses "4399B Metal Structures", "4399D other specialized construction works" and "4399 rental with construction equipment operator" are also not tracked within the NAF4 4399 class. The indices relating to the NAF4 "4339 other finishing work" are not published by application of rules of statistical secrecy. They are nevertheless included in the calculation of the higher level IPEA indices, in particular in the "all Works" index. New construction work, or similar to new construction, renovation or rehabilitation work carried out after almost total demolition, processing work in transformation of buildings from one use to another another use are excluded from the survey. Works which consist only to supply materials are also excluded as it is considered like a commercial activity.

The collection of the "raw prices" price series takes place in two steps:
-The first step is to select legal units and question them on their types of works in order to define with them some "Response series" representative of their activity in the field of investigation. The interview is done face-to-face by an INSEE’s surveyor;
-The second step consists of a interrogation of the legal unit on the prices of their "response series" defined in the first step. The legal unit must then respond to an online or paper questionnaire. More than 2,000 "response series" participate in the calculation of IPEA indices each quarter.