Dear Iain

COVID-19 Infection Survey Statistics

As you are aware, we recently undertook a review of statistics from the ONS COVID-19 Infection Survey. A summary of our review, findings and recommendations is provided below, and set out in more detail in the annex to this letter.


In May 2020 we carried out a rapid review of the first statistics from the ONS COVID-19 Infection Survey. We endorsed the approach taken by ONS and partners to deliver timely statistics about a rapidly evolving national emergency – in particular, we welcomed ONS’s agility in launching and developing the survey, its commitment to continually improve and evolve the statistics, and the ongoing engagement with devolved administrations to extend the survey UK-wide. We asked that, as the survey and statistics continued to be developed, ONS carefully considered how to communicate the statistics and technical terms to a range of users. We noted that maintaining good response rates would be essential to presenting robust results.

Since our initial review, the COVID-19 Infection Survey has increased from a survey of approximately 28,000 people tested per fortnight in England, to over 150,000 people tested per fortnight across the UK. Given the expansion of the survey and its public importance, we agreed with your team that we would undertake a more in-depth review against the Code of Practice for Statistics.

Summary of our findings

ONS should be proud of the contribution the survey has made to government and public understanding of the pandemic. We consider that ONS has provided clear and relevant insights for users in its weekly bulletins and analysis articles. We are impressed by the strong working relationships that ONS has developed with its survey provider and academic partners, which have supported the effective scale-up of the survey across the UK and facilitated knowledge sharing and expert scrutiny.

We have identified some areas to support further development of these statistics to move towards complying with the highest standards of the Code of Practice – these are described in more detail in the annex. While we recognise the competing priorities that ONS needs to balance, we would like to see a focus on increased transparency and engagement with users. We would also like to see you improve the communication of methods for general and expert users.

We would like to thank all the teams in ONS who engaged with us so positively throughout the review process. The efforts of staff at all levels working under considerable pressure are commendable. We look forward to hearing from you as you continue to develop these statistics and are happy to discuss a more formal assessment or provide further advice in due course.

Yours sincerely

Ed Humpherson

Director General for Regulation

Annex: OSR review findings and recommendations – ONS COVID-19 Infection Survey statistics (Word document)

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Response from Iain Bell to Ed Humpherson : COVID-19 Infection Survey Statistics