The Office for National Statistics has announced that it will seasonally adjust monthly construction output data, with the change first applied to May 2013 output figures.
The change could not take place beforehand as the ONS needed three years of monthly data in order to apply a robust adjustment, under recommendations by Eurostat. It was around three years ago that the ONS had switched from reporting output quarterly to a monthly data series, though it has continued to issue quarterly figures.
By seasonally adjusting the figures, more robust month on month comparisons can be made, as adjustments are made to the figures to account for seasonal affects, including anticipated slowdowns in winter and tax year-ends.
The seasonally adjusted monthly output data will be first published in July 2013, when the ONS reports on output in May, with the change expected to be confirmed in the Quarterly National Accounts released on 27 June. The seasonally adjusted monthly figures will also be applied to quarterly totals, but it is anticipated that the direction of growth rates will not change significantly.
Glenigan economics director Allan Wilen welcomed the move, saying that “the benefit is that it will allow you to compare one month over any other month. it will give a much better idea of where the trend is going”.
Commenting on the construction output figures released today by the ONS, the agency’s head of the retail sales index and construction Kate Davies said that feedback was that the poor UK weather conditions during March, and most of the quarter, had pulled output down.
Output was down 6.5% in Q1 2013 compared with Q1 2012, and 2.4% down on Q4 2012.
“There’s not even just a private/public split in the data released today,” she said.