Rebased index and improved methodology
The RSI will be rebased onto 2000=100 when it is next published on 24 October. ONS has taken this opportunity to make a number of improvements to the RSI that will be in introduced with the rebased series.
On 30 September 2003, ONS published a long run dataset containing the headline RSI series on the new basis. This is to enable users to prepare for the switch-over to the rebased series on 24 October. This early release is consistent with the National Statistics Protocol on Release Practices.
Many aspects of the methods and systems used to produce the Retail Sales Index (RSI) have been reviewed and updated. These improvements represent the largest investment of methodological development for the RSI in twenty years. They ensure that RSI methods are soundly based and incorporate standard methods used for other business surveys. An article describing the improvements being introduced and giving an indication of the impact of the improvements on the headline RSI was also published on 30 September.
The growth of the new RSI is broadly similar to the previous series over the period 2000-2001. From late 2001 the new series shows consistently stronger growth compared with the previous series. This is a result of treating fewer returns as outliers, the use of improved deflators, and taking on late data that were not available at the time of publication of the previous series.