The biannual investment survey has been revised from autumn 2021 onwards. Like all business surveys, it is now a qualitative survey that focuses on trends - increase, stabilisation, decrease - and no longer on investment amounts. The investment indicator is therefore an indice, not a percentage of variation. The quantitative data collected before the autumn of 2021 for the manufacturing industry have been transformed in order to fit with the new concepts. The businessrzalted services sector has only been included in this survey since autumn 2021.

The results of the survey are subject to statistical processing involving a double weighting scheme. On the one hand, the individual responses are weighted to take account of the relative importance of each firm on the basis of the salaried employment it declares in the survey. On the other hand, when aggregating the responses at the level of the sector concerned (total manufacturing or business services), account is taken of the relative importance of the sub-branches of activity. The second stage of the weighting scheme is based on the VAT data relating to investments.