The seasonally adjusted IMACEC series is obtained from the aggregation of its seasonally adjusted components. These are computed using the X-13 ARIMA-SEATS program (www.census.gov) and a specific parametrization for each component. The parametrization is updated with the annual revision of national accounts. The seasonal adjustment sample starts in 2018.
For an extensive description of the seasonal adjustment process refer to Studies in Economic Statistics N° 98 available in www.bcentral.cl