Dear Ed,

My team contacted the Office for Statistics Regulation in March this year when we became aware of an error affecting the data used in the Scottish Cervical Screening Programme statistics for the years 2016/17 to 2021/22i. These statistics report on the number of eligible women (and anyone with a cervix) who have a screening test and provide intelligence about the delivery of this vital public health intervention. The impact of the error on the previously published statistics is relatively small for national-level estimates and does not alter the overall conclusions drawn. The impact is somewhat greater for some sub-groups. It is important to note that none of these issues affected the running of the programme and all those eligible were invited for a cervical screen appropriately.

We have been sharing updates with you as our investigations of the error have progressed. Notices were also added to the previous publications and open data portal to alert users.

We discovered the error as part of our work to develop new statistics about the screening programme to reflect changes to the way it is now implemented and the availability of new data to measure its delivery. Following the discussion with your team on 8th May about publication dates, I am writing to confirm our plans and to request a temporary suspension of this series’ accredited status. The next publication will instead be labelled as official statistics in development due to the methodological changes we have made to these statistics (e.g. using a new data source), the introduction of new KPI measures, and the errors with the previous data. I would welcome a review by your team following the statistics’ publication to determine whether the accredited status can be reinstated following the work we have done to address the previous issues and better meet user needs.

We are planning to release the new statistics, and the revised estimates for the 2016-17 to 2021-22 period, on 29th July 2025, with a preannouncement on 28th May. An explanation of the revisions made and the issues we identified through our work to develop the new statistics will be outlined in an FAQ document to be published alongside the main statistics release. For additional transparency, the code used to identify the eligible population and report on the programme KPIs will also be published. An extract of the FAQ document is provided as an annex to this letter for your information.

I would like to thank your team for their advice and support during our investigation of this issue. I am copying this letter to Alastair McAlpine, Scottish Government Chief Statistician.

Yours sincerely,

Scott Heald

Director, Data and Digital Innovation

Head of Profession for Statistics

 

 

Cervical Screening Data FAQs

What happened?

· The previous method for producing these statistics relied on aggregate data extracted from systems by an external IT provider, who applied all selection criteria and calculations. The new statistics use individual-level data which enabled PHS to identify discrepancies in the previously supplied aggregate data. For example, the time periods for each year not matching the dates in the specification provided and errors in the criteria used to select the eligible population to be included in the statistics.

· In previous publications, the terms “coverage” and “uptake” were used interchangeablyii, although it has always been coverage which has been measured. Both will be presented in the new publication, as the new KPIs for the programme require reporting on both coverage and uptake.

· None of these issues affected the running of the programme and all those eligible were invited for a cervical screen appropriately.

What is different now?

· PHS now receive patient level data extracts and analysts apply agreed methodology to create the cervical screening statistics, including identification of the eligible population for coverage statistics.

· PHS has been working with a group of experts who work across the whole cervical screening and treatment pathway to develop and sign-off the methodology for the new statistics. The R code used to identify the eligible population and report on the programme KPIs will be published alongside the statistics.