The Various Tables

This chapter presents a complete and detailed example of seasonal adjustment with the X-11 method. The series that is used in this example is a monthly series; it is in such cases that the softwares’ options are most numerous and complex. The series studied X _t is the monthly index of industrial production in France between October 1985 and March 19951. The series is represented in the top panel of Figure 4.1, which gives a decomposition plot. The seasonal factors S _t (Table D10) are graphed in the third panel, and, in the case at hand, the trading-day factors D _t (Table C18) are provided in the fourth panel. These two sets of factors are used to compute the seasonally adjusted series A _t (Table D11), which is shown with the original series in the top panel, and with the trend-cycle C _t (Table D12) in the second panel. Finally, the irregular component I _t (Table D13) is graphed in the bottom panel. It is obtained by removing the trend-cycle from the seasonally adjusted series.