Working Paper No. 93/2 X11 TIME SERIES DECOMPOSITION AND SAMPLING ERRORS

This Working Paper Series is intended to make the results of current research within the ABS available to other interested parties. The aim is to present accounts of ABS developments and research work or analysis of an experimental nature so as to encourage discussion and comment. Views expressed in this paper are those of the author(s) and do not necessarily represent those of the Australian Bureau of Statistics. Where quoted or used, they should be attributed clearly to the author(s). There is considerable interest in analysing the effect of sample design on time series decomposition into components such as trend, seasonal and residual. One of the main deficiencies in past analysis has been a lack of a realistic model of an officially used time series decomposition method. This paper demonstrates a realistic approximation for X11 and shows how such a model can be used to analyse the effect of sample design on time series decomposition. 1 TIME SERIES DECOMPOSITION USING X11 AND SAMPLING ERROR