§ Mr. DobsonTo ask the Chancellor of the Exchequer, further to his answer of 12 November,Official Report, column 501, what was the net effect of each of the changes set out in the Chief Secretary's answer of 12 November in each month since it was introduced.
§ Mr. MellorFollowing is the available information:
- (a) Adjustments to statistics of oil exports: Prior to October 1989 direct exports of crude oil were under-recorded in Customs and Excise data, and in the trade figures published by the Central Statistical Office, by amounts which average £40 million—440,000 tonnes—per month in the first three quarters of 1989. Since October 1989 this under-recording has been eliminated, but some oil exports are still reported with a delay. The Central Statistical Office therefore includes in its statistics estimates of the amount of exports still to be reported. The adjustments for the latest month have averaged £12½ million—120,000 tonnes—per month over the last three months.
- (b) Improved seasonal adjustments: Some indication of the impact of regularly updating seasonal adjustment factors can be obtained by comparing the adjusted figures initially published for each month with the revised figures published a month later, though these revisions also incorporate any necessary amendments to raw data. Since January 1990 when the regular updating was initiated the revisions to the balance of visible trade, irrespective of sign, have averaged £30 million per month.
- (c) Progressive development of detailed methodology: The various refinements referred to in the earlier reply are such that they have been integrated into the monthly cycle of processing and without
27 retrospectively reconstructing the statistics using the old methodology it is impossible to determine what their effect has been.