On the go: The Office for National Statistics has made an error in the retail prices index, leaving the figures for March and June this year 0.1 percentage points adrift. The possible impact of the mistake on the stock market led to the ONS publishing a statement outside of trading hours late on Thursday.
The error was caused by an issue with the 2017 to 2018 Living Costs and Food Survey dataset, which underpins the RPI.
The ONS statement says: “If the corrected LCF dataset had been used to calculate the 2019 RPI weights, it would have led to an upward revision of 0.1 percentage points in the RPI annual growth rate in March 2019, from 2.4 per cent to 2.5 per cent, and a downward revision of 0.1 percentage points to the June 2019 rate, from 2.9 per cent to 2.8 per cent. No other month’s annual growth rates have been affected.”
It points out: “Using the corrected LCF data would also have led to an upward move of 0.1 index points to the March 2019 RPI, from 285.1 to 285.2, and a downward move of 0.1 index points in each of April (288.2 to 288.1), May (289.2 to 289.1) and June (289.6 to 289.5). These index changes would have only affected the annual growth rate for March and June 2019.”
In line with ONS policy, the ONS is not revising the RPI retrospectively. This error has been corrected from the July publication, which will be published on Wednesday August 14.
As the earlier months’ publications will be on the previous basis, there will be a discontinuity between July’s and June’s index levels.
There is no impact on the consumer price index including owner occupiers’ housing costs (CPIH) or the standard CPI, for which weights are calculated using more comprehensive national accounts data sources.
