Office for National Statistics says it miscalculated seasonally adjusted retail sales data
Following its corrections, the ONS has revised down the quarterly growth rate of retail sales from 1.3% to 0.7% in Q1 and up from 0.2% to 0.3% in Q2.
This will have a slight impact on the UK’s growth data for the first quarter of 2025.
Retail sales is used to measure the output of the retail sector and part of household expenditure. It accounts for 4.8% of GDP.
This means that the contribution of retail sales to GDP growth has been revised down from 0.06pp [percentage points] to 0.03pp in the first quarter and is unrevised to two decimal places in the second quarter.
Despite the change in contribution, and all else being equal, GDP in Quarter 1 2025 would have been unchanged to 1 decimal place at 0.7%.
I apologise both for the delay to this release and the error in how we have been seasonally adjusting these data.
Many retailers report their sales on a ‘retail calendar’ basis which split the year into planning and reporting periods that have the same number of weekends, which tend to have a larger percentage of sales, and consistently align holidays and shopping events, such as Easter and Black Friday, each year. Reflecting that, our retail sales figures are collected for blocks of four weeks, four weeks and then five weeks (a ‘4-4-5′ approach) and can both sit within a month or span multiple months. This adds complexity to our seasonal adjustment process, given the need to align the collected data to calendar months. The process is complicated further by the pattern of the blocks of four and five weeks sometimes changing.
Our review revealed that we had not seasonally adjusted data correctly because we did not properly account for the adjustment in retail reporting calendars. We have now corrected for this mistake.
Continue reading…Office for National Statistics says it miscalculated seasonally adjusted retail sales dataFollowing its corrections, the ONS has revised down the quarterly growth rate of retail sales from 1.3% to 0.7% in Q1 and up from 0.2% to 0.3% in Q2.This will have a slight impact on the UK’s growth data for the first quarter of 2025.Retail sales is used to measure the output of the retail sector and part of household expenditure. It accounts for 4.8% of GDP.This means that the contribution of retail sales to GDP growth has been revised down from 0.06pp [percentage points] to 0.03pp in the first quarter and is unrevised to two decimal places in the second quarter.Despite the change in contribution, and all else being equal, GDP in Quarter 1 2025 would have been unchanged to 1 decimal place at 0.7%.I apologise both for the delay to this release and the error in how we have been seasonally adjusting these data.Many retailers report their sales on a ‘retail calendar’ basis which split the year into planning and reporting periods that have the same number of weekends, which tend to have a larger percentage of sales, and consistently align holidays and shopping events, such as Easter and Black Friday, each year. Reflecting that, our retail sales figures are collected for blocks of four weeks, four weeks and then five weeks (a ‘4-4-5′ approach) and can both sit within a month or span multiple months. This adds complexity to our seasonal adjustment process, given the need to align the collected data to calendar months. The process is complicated further by the pattern of the blocks of four and five weeks sometimes changing.Our review revealed that we had not seasonally adjusted data correctly because we did not properly account for the adjustment in retail reporting calendars. We have now corrected for this mistake. Continue reading…
