Export Statistics Scotland: methodology

Comparison with ONS International Trade in UK Nations, Regions, and Cities

The Office for National Statistics (ONS) provides an estimate of Scotland’s international trade in goods and services. These are official statistics in development.

The ONS uses a different methodology to produce these estimates than that used to produce ESS estimates. ESS defines trade on a movement of goods basis, which means that goods must physically move from Scotland to another geographical location to be counted as an export. On the other hand, ONS defines trade on a balance of payments basis, which means that trade is only counted when a change of ownership has taken place. If a product moves across a customs border but remains under the same ownership, this is not counted as trade, using this method. Using the balance of payments method will often result in a higher estimation of trade, which is likely to be one of the reasons why the ONS estimates are higher than ESS estimates.

There are also differences in how trade is attributed to Scotland. ONS begin with a trade value for the UK, and then apportion trade to Scotland using the proportion of employees in each region of the UK. In contrast, ESS finds businesses that have economic activity in Scotland, based on Scottish local units from the Inter-Departmental Business Register (IDBR), and then estimates the export activity of these Scottish companies.

The ONS also treats oil and gas differently to ESS. Scottish Government official trade statistics exclude trade in oil and gas. For ESS, estimates of Scottish exports exclude any exports of oil and gas extracted from the UK continental shelf. This means that the ESS export estimate excludes companies classified as 'Extraction of crude petroleum' [SIC (2007) 6.1] and 'Extraction of natural gas' [SIC (2007) 6.2].

In the latest release of ONS International Trade in UK Nations, Regions, and Cities, ONS introduced an extra-regio category, which includes parts of the national economic territory which cannot be attached directly to a single region, including some offshore oil transactions and territorial enclaves. However, the values for this category are quite low compared to values for mineral fuels seen in HMRC Regional Trade Statistics (RTS), and trends in the data suggest that the ONS estimates for Scotland are still heavily impacted by oil and gas trade. HMRC RTS statistics show that Scotland’s exports of oil and gas were worth between £6 and £14 billion each year from 2016 to 2021. Adding this to the ESS export estimates would bring them more in line with the ONS estimates, which suggests that inclusion of some oil and gas exports may be contributing to the higher trade values seen in the ONS data.

These different approaches are likely to result in the differences in the Scottish export values shown in Figure 7.

Figure 7. ONS estimates of the value of Scotland’s international exports are much higher than ESS estimates but the trend between 2019 and 2021 is the same

Estimated value of Scotland’s international exports from 2019 to 2021, sourced from ESS 2021 and ONS International trade in UK nations, regions and cities: 2021