Preparation of data

The first phase of the seasonal adjustment process includes a careful review of the raw (original) data series: are data series of sufficient length and quality available, are there breaks in the series that needs to be considered and perhaps corrected for. The chapter provides brief recommendations on the required length and quality of the original series. It presents the decomposition of the original data time series into its trend-cycle, seasonal and irregular components. Seasonal adjustment means to correctly identify and estimate the seasonal component in the original data and removing this to obtain the seasonally adjusted series. The chapter also discusses calendar effects and the treatment of outliers. The chapter ends with explaining how to prepare data in the correct format for seasonal adjustment with JDemetra+.

Sustainable Development Goals:

Decent Work and Economic Growth