In September 2017, the seasonally adjusted production index in the construction sector reflected a decrease of 0,05% compared to August 2017. The calendar adjusted production index reflected a decrease of 0,37% compared to September 2016.
Results are based on the survey about activity in the building and civil engineering industry (50M).
The attached Excel file contains an overview of indices per sector.
Results for the reference month and the two last months are provisional.
From the release of March 2017 on January 2017, the index of production in construction will be published separately. The deadline for publication will be one month and 15 days after the reference month.
The software Jdemetra+ replaced Demetra+ for the seasonal adjustment of the production indices in construction as from the release of March 2017 on January 2017.
The method used has remained unchanged. It is still the Tramo seats method based on the ARIMA models.
However, we took the opportunity of the software change to improve the models used.
We replaced the models based on a regression comparing every day of the week by models based on a regression comparing the working days of the week with the weekend days, which are more suitable for this sector.
This change may be an explanation for the revisions observed in the series adjusted for season and working days and in the trends compared to the previously released series.