Most of the Euro-zone economic short-term indicators are computed through aggregation from Member States data. The seasonally adjusted figures can be calculated by seasonally adjusting the aggregate (direct approach) or aggregating the seasonally adjusted national data (indirect approach)....

In this paper, we investigate the impact of the adjustment for seasonal effects with different seasonal adjustment methods, the possible pre-treatment for calendar effects and the different order of aggregation and adjustment for the determination of the turning points of the European business...