Yesterday the Office of National Statistics radically altered the National Average Earnings Index, rebasing it to average year 2000 = 100 instead of 1995 = 100. Page 6 of the October issue of "Labour Market Statistics", published yesterday, includes the following brief announcement:

"THIS MONTH
Average Earnings Index

The index numbers for all AEI series have been re-referenced to 2000 = 100 in line with other National Statistics outputs. Previously published growth rates have not been revised as a result of this change."

Advance notice in the September "Labour Market Statistics" was similarly succinct:

"Next month will see the regular annual re-bench of the AEI which will update weights to July 2002. The index numbers for all series will also be re-referenced to 2000=100, in line with other National Statistics outputs. These processes will not lead to revisions to previously published growth rates. The annual updating of seasonal adjustment weights will occur at the same time."

Retrospective adjustment of figures in the NAE table is a growing source of concern. Recent experience indicates that even an annual check for changes to previously published figures may no longer be sufficient.