Dear Ms Brown, 

I am writing to make you and the Committee aware that on 30 August 2022 the Office for Statistics Regulation (OSR) has published an update to our March 2021 review of the COVID-19 Infection Survey (CIS). The CIS measures how many people living in Scotland, Wales, Northern Ireland, and England test positive for a COVID-19 infection at a given point in time, regardless of whether they experience symptoms. In Scotland, the statistics contribute to ongoing surveillance of the coronavirus pandemic, along with other sources such as genomic sequencing to identify new variants, testing in health and social care settings, and wastewater surveillance.  

The CIS is therefore a key component of public health surveillance in Scotland. In line with its importance, we have maintained a close regulatory focus on how the survey is conducted and on how the results are calculated and presented. The background to our latest review is that in June 2022, the Office for National Statistics (ONS) announced changes to the survey, introducing a digital questionnaire and sending swab and blood sample kits by post. These changes reflected plans to maintain a scaled back version of the CIS set out by the UK Government in its Living with COVID-19 plan.  

In light of the ONS’s changes, we agreed with the ONS that we would undertake a further review of the statistics against the Code of Practice for Statistics. This update looks at whether, and to what extent, the statistics from this survey continue to serve the public good.  

Our review highlights the ongoing value of the CIS. Given the cessation of the REACT study and changes in testing regimes by governments across the UK, these statistics are now the most up-to-date, reliable source on COVID-19 infections. They contribute to scientific advice provided to governments, including the Scottish Government, informing decisions on the ongoing management of the pandemic. In Scotland, the statistics are reported on weekly by Public Health Scotland in its COVID-19 statistical report. Public Health Scotland states that the statistics are the “current best understanding of community population prevalence”. The statistics from the CIS contribute to the estimate of the reproduction (R) number for Scotland, also published in Public Health Scotland’s report. This provides an assessment of whether the pandemic is shrinking or growing. And there is a high level of public interest in the survey – people really value the statistics and many use them to make day-to-day decisions, including potentially serious decisions for those vulnerable to COVID-19.   

Our review makes several recommendations to the ONS regarding ongoing improvements to the statistics: 

  • The ONS should ensure that devolved administrations have appropriate input at the programme level. The ONS has built good working-level relationships with the devolved administrations, including statisticians in the Scottish Government. However, we consider that devolved administrations would benefit from increased engagement at a senior level, for example to ensure that they can input to decisions relating to changes to the survey.  
  • The ONS should continue to inform users about the impacts of the change in mode to digital data collection on the statistics. We found that for the statistics to remain as valuable as possible, it is important for many users, particularly those in the devolved administrations, that granular breakdowns are still available following changes to the survey mode. We are encouraged to see ONS’s plans to understand and publish information about the change in mode. This includes information on any impact on the response rates and sample, and therefore the representativeness of the survey. The ONS recently published their initial findings on the effects of the change of mode which offers a first insight into many of these aspects. 
  • The ONS should ensure it keeps users informed about development plans, even if these plans are tentative and subject to change. While we appreciate that the ONS is working in a fast-moving environment and that decisions about the survey may sit with other partners, we consider that it could have done more to keep users informed in a clear and timely way about planned or potential changes to the survey. It will be particularly important for the ONS to keep users informed about the future of the survey as the financial year ends.
  • The ONS should also consider how the CIS can be adapted to play a role in understanding public health in future. The coronavirus pandemic reinforced the need for statistics to inform society about public health. In our review of lessons learned for health and social care statistics during the pandemic we highlighted the need for statistics producers across the UK to continue to develop outputs which go beyond operational data in order to support a better understanding of public health.  

I know the Committee is currently holding evidence sessions for their pre-Budget scrutiny on the COVID-19 strategic framework and are looking specifically at surveillance measures. I hope this letter will help inform the Committee’s work on the subject. 

Please do let me know if you have any questions.  

Yours sincerely  

Ed Humpherson
Director General for Regulation