TECHNICAL NOTE

REVISIONS TO TREND ESTIMATES


EFFECT OF NEW SEASONALLY ADJUSTED ESTIMATES ON TREND ESTIMATES

1 The most recent trend estimates published in this release are likely to be revised when next month's seasonally adjusted estimates become available. To assist readers of this publication in analysing retail trends, the approximate effect of the two possible scenarios on the previous trend estimates of the percentage change in total retail turnover for Australia are presented below. For more information see the trend estimates section of the Explanatory Notes.

1 The May seasonally adjusted estimate of retail turnover is 1.0% higher than the April estimate.
2 The May seasonally adjusted estimate of retail turnover is 1.0% lower than the April estimate.

2 Under concurrent seasonal adjustment, the most recent seasonally adjusted and trend estimates are likely to be revised when original estimates for subsequent months become available. The trend revision is a combined result of the revision of the seasonally adjusted estimates and the revision derived from the use of asymmetric moving averages as future data become available (for more information, refer to paragraph 28 in the Explanatory Notes). ABS research shows that about 75% of the total revision to the trend estimate at the current end of the time series is due to the use of different asymmetric moving averages when the original estimate for the next time period becomes available. To assess the reliability of the trend estimate at the current end, the 'what-if' chart presents trend estimates under two different scenarios of the next time period. The chart shows only the impact due to the changes of the asymmetric moving averages and does not include the unknown impact of revision to seasonal factor estimates that would arise when the original estimate for the next time period becomes available.