10. Measurement of data
You will find more information on how to measure data in our main data sources in the following versions:
There have been large movements in UK gross domestic product (GDP) throughout the coronavirus pandemic (COVID-19). This mainly responds to the public health restrictions and voluntary social distancing that have been established during this period. Given the size of these effects, it has focused on where the economy is, relative to its pre-coronavirus pandemic levels.
In the UK, we make monthly and quarterly GDP estimates. However, these will not necessarily provide the same estimate of the position of the economy, relative to its pre-coronavirus pandemic levels. This is largely because monthly GDP estimates are based only on the measurement of GDP output, while quarterly GDP estimates reflect the average of the three approaches (production, revenue, and expenditure).
The coronavirus pandemic has posed many measurement challenges, as shown in our article, The Coronavirus and the Effects on GDP, which have created more uncertainty around our approaches. This has led to an initial divergence between output and the average estimate, which is then reflected in how we compare monthly and quarterly GDP estimates. More information is available in our article, Measuring UK Gross Domestic Product Monthly and Quarterly during the coronavirus pandemic (COVID-19).
Estimates for the construction industry within monthly GDP will differ from those published in the publication of construction output, as they take into account both the products produced and the inputs consumed by the industry. There are also some differences in coverage, given the use of the Annual Business Survey in its compilation.
Within the monthly GDP publication, government data are obtained on a quarterly basis; a monthly forecast is used to estimate monthly round data until quarterly data is available. While this is a standard practice with many of our data sources, anticipating the behavior of a series during a pandemic, particularly for health and education, entails more uncertainty than usual, for which caution is advised when looking at monthly estimates beyond. the last quarter published.
The National Statistics Office (ONS) is aware of the reclassifications or relocations of companies that may affect these published estimates of GDP and associated breakdowns. The ONS is monitoring the data and will try to implement the resulting changes to the national accounts as soon as possible.
Seasonal adaptation and special events
Previous experience in 2002 and 2012 showed that the Jubilee and the holiday season could lead to more volatile movements in the monthly trajectory of gross domestic product (GDP) in May and June. As part of our usual practice, prior adjustments are made for calendar effects (if statistically significant), such as returns that do not meet the standard trading period, holidays, Easter, and Christmas Day. Adjustments for repeated and foreseeable effects are estimated and removed from the seasonally adjusted final series, e.g., a permanent change in the seasonal pattern. Adjustments for effects that are not repeated are estimated and removed during the seasonal adjustment process, but are then re-incorporated into the final seasonally adjusted series, e.g., the extreme time effect. We will continue to review these adjustments periodically.
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