Dear Ms Baillie,

Thank you for your letter of 6 January about the Deputy First Minister’s use of statistics from the Coronavirus Infection Survey.

In his interview the Deputy First Minister was drawing on the most recent data then available. Mr Swinney’s office has told us that he was aware of the time period covered by the survey and was speaking in the broader context of the different policies on COVID-19 in Scotland and England throughout this winter. However, listeners could have taken the impression that he was referring to the period after Christmas when new restrictions came into force. When using statistics in public communication it is important to be clear about what the data are measuring, and the choice of time period is all the more important in a rapidly changing situation.

As you will no doubt now be aware, on 7 January Public Health Scotland (PHS) published updated analysis of hospitalisations ‘because of’ COVID-19 to complement data on hospitalisations ‘with’ COVID-19. This was an additional analysis to provide fast turn around results relating to Omicron. In future, PHS plans to continue using patient discharge data from the national Scottish Morbidity Records (SMR01), which it first published on 1 December 2021 and is subject to a time lag of two to three months.

Yours sincerely,

Sir David Norgrove

Related links:

Jackie Baillie to Sir David Norgrove – Deputy First Minister’s statements on COVID infections in England and Scotland

Willie Rennie MSP to Sir David Norgrove – First Minister’s statements on COVID infections in England and Scotland

Sir David Norgrove response to Willie Rennie MSP – COVID infections in England and Scotland