1.1 The ABS currently recalculates most seasonal and trading day factors on an annual basis. This paper summarises recent investigations into the benefits of revising the factors on a monthly rather than annual basis, and presents recommendations for implementing the change for the Retail Trade series. While the paper concentrates on the Retail Trade series, the implications for other ABS series are also discussed.
1.2 This paper assumes the reader has at least a basic understanding of the seasonal adjustment process. If an understanding of seasonal adjustment is required, the feature article ‘A Time Series Decomposition of Retail Trade’ in the August 1991 Australian Economic Indicators (Cat. no. 1350.0) should be consulted.
1.3 Estimates of retail turnover in this paper are obtained from the monthly Retail Business Survey which covers employing businesses in most retailing industries (the most notable exceptions being motor vehicles, boats and service stations). Full details of the industries included in the Retail Trade series are in the attachment. The two largest retailing industry groups, Food retailing and Hospitality and services, contribute over 50% of total retail turnover. The Household good retailing, Other retailing and Department stores groups contribute about another 30% to total turnover.
1.4 All employing businesses with at least one retail establishment are included in the scope of the survey.
The attached document provides details of the investigations undertaken and recommends that concurrent seasonal adjustment be included in the Retail Trade series from the April 2000 reference month. Comments on the issues raised in this paper (especially those summarised in paragraph 4.12) are required by 31 January 2000.