Ed Humpherson, Director General for Regulation, Office of Statistics Regulation to Philp Rycroft, Permanent Secretary, Department for Exiting the European Union (DExEU).
On 13 October 2018 Sir David Norgrove, Chair of the UK Statistics Authority, received correspondence from the Rt Hon Lord Lilley which asked him to investigate the statistics quoted in paragraph 16b of the White Paper on The Future relationship between the United Kingdom and the European Union. It asked specifically about the statement that “Under the UK’s proposals, it is estimated up to 96 per cent of UK goods trade would be most likely to be able to pay the correct or no tariff upfront, with the remainder most likely to use the repayment mechanism”.
In circumstances like this there are often a range of plausible estimates. It would have been helpful if an explanation of the calculation, assumptions and impact of these assumptions had been published alongside the White Paper to allow the public to understand the basis of the figure.
Our Code of Practice for Statistics requires that assumptions and methodologies are published at the time a claim is made, or earlier. In line with the Code I would encourage you to publish details of your estimate of 96 per cent at the earliest opportunity.
Sir David Norgrove to Rt Hon the Lord Lilley (November 2018)
Rt Hon the Lord Lilley to Sir David Norgrove (October 2018)