Many published seasonally adjusted series are composites of individual seasonally adjusted series: for instance, subcategories sum to main categories and regions sum to the U.S. total. Many seasonal adjusters who publish these indirect totals use seasonal adjustment programs to adjust the individual series and then combine them using separate software. The U.S. Census Bureau uses X-12-ARIMA to perform seasonal adjustment. X-12-ARIMA, like X-11-ARIMA before it, has the capability to combine adjusted series and provide indirect adjustment diagnostics that are not available when the individual adjustments are combined using outside programs. Further expansions to the program will allow users to perform model-based seasonal decomposition as well as the traditional moving-average method of X-11. We investigated the issues involved when performing indirect seasonal adjustments under different circumstances including subjective prior adjustments for individual series and totals with mixed decomposition types (multiplicative vs. additive and semiparametric vs. model-based adjustments). From our experiences we describe what users should know before performing indirect seasonal adjustment.
RegARIMA model, Time series
This symbol indicates a link to a non-government web site. Our linking to these sites does not constitute an endorsement of any products, services or the information found on them. Once you link to another site you are subject to the policies of the new site.