UK Statistical System UK Statistics Authority Code of Practice
Compliance check

Siobhan Tuohy-Smith to Stephanie Howarth: Estimates of additional housing need

Dear Stephanie

We have completed our review of Welsh Government’s Estimates of additional housing need. These statistics are currently published as official statistics. Our findings are summarised in a separate report.

During our review we found the presentation of the estimates to be of a high standard. We commend the team for its leadership in taking a unique, open and transparent approach in developing these new official statistics based on the available official sources, in line with the Code of Practice for Statistics. We have also identified some areas where these estimates can be strengthened in line with the Code.

We have shared our findings with your analysts and appreciate their positive engagement during this process. We have agreed that the team will review and consider the recommendations as they develop future estimates of additional housing need. We will continue to engage with the analytical team responsible as they take forward the recommendations.

I am copying this letter to Rachel Dolman and Melanie Brown the lead analysts for these estimates.

Yours sincerely

Siobhan Tuohy-Smith

Assessment Programme Lead

Related links: Mark Pont to Stephanie Howarth, Peter Whitehouse, Tracy Power, and David Marshall: Review of household estimates and projections for Wales, Scotland, and Northern Ireland 

Siobhan Tuohy-Smith to Jessie Evans: Compliance review of statistics from the Cyber Security Breaches Survey

Dear Jessie,

Compliance review of statistics from the Cyber Security Breaches Survey

We have completed a compliance review of the Cyber Security Breaches Survey statistics produced in partnership by the Department for Science, Innovation and Technology (DSIT) and the Home Office against the standards of the Code of Practice for Statistics. These statistics are currently produced as official statistics.

Our review sets out our view on how the statistics from the Cyber Security Breaches Survey meet the standards of the Code. The review identifies a range of areas where the statistics demonstrate trustworthiness, quality and value, and makes three recommendations for improving the quality and value of the statistics.

I am grateful for the constructive engagement from your team throughout the review and hope our findings inform the ongoing development of these statistics.

I am copying this letter to John Wilkins, Chief Statistician at the Home Office; and Saman Rizvi, Statistician, Cyber Security & Digital Identity team at DSIT.

Yours sincerely,

Siobhan Tuohy‑Smith
Assessment Programme Lead

Related

Compliance review of statistics from the cyber security breaches survey

Rob Kent-Smith to Liz McKeown and Sarah Henry: Review of ONS’s Treatment of Seasonality in Quarterly GDP statistics

Dear Liz and Sarah

Today we published our Review of ONS’s Treatment of Seasonality in quarterly GDP.

This review was prompted by concerns from some users, and media commentators, about the effectiveness of seasonal adjustment in the post pandemic period.

In recent years, quarterly (and monthly) GDP statistics published by ONS have shown stronger growth in the first half of the year than in the second half. This recent pattern of stronger growth in the first part of the year has reflected, at least in part, a series of one-off events (for example the bringing forward of economic activity in advance of the expected levying of increased tariffs).

Current statistical tests show no evidence of significant residual seasonality in quarterly or monthly GDP. However, emerging seasonal patterns can take several years to detect using standard methods. This means there remains a risk that early signs of change may not yet be visible in the statistical tests. It is important that ONS keeps and open mind as more data becomes available to understand this phenomenon.

To strengthen ONS’s approach going forward, we recommend that ONS should:

  • Seek external assurance on its approach, particularly on the detection of emerging seasonal signals.
  • Should continue increasing transparency around its methods and uncertainties.
  • Complete work to rebuild and stabilise the specialist team responsible for seasonal adjustment.

We note and welcome the steps that ONS has already taken to address concerns in each of these areas. We look forward to considering evidence on further actions ONS provides as part of its regular reporting on progress with its plans for economic statistics.

Yours sincerely

Rob Kent-Smith

Deputy Head of the Office for Statistics Regulation

 

Related Links:

ONS response to the OSR compliance review on the treatment of seasonality in quarterly GDP

Ed Humpherson to Scott Heald: Temporary suspension of accreditation: Breast Cancer Screening Statistics and Scottish Health Costs

Dear Scott,

Thank you for your letter of 24 February outlining the data quality issues affecting Public Health Scotland’s breast cancer screening statistics and Scottish Health Services Costs (or “Costs Book”) publication.

Given the issues you have described, I agree to your request for the temporary suspension of accreditation for both sets of statistics. I note that you are considering designating these as official statistics in development while you continue your investigations and improvement work. We have published Official Statistics in Development guidance to help producers understand when and how to use this label.

In your letter you explain that the data quality issues affecting the breast cancer data for Scotland has affected all statistics published from 2015/16 onwards. Therefore, the suspension should also cover those earlier releases, and a notice should be published to explain the issue to users and outline the work under way to investigate it. Given this is the second issue with aggregate data from this IT supplier, we welcome your investigation into whether the problem affects other data submissions.

I welcome your commitment to keeping OSR informed as work progresses on both publications. Once the necessary improvements have been delivered, we would be happy to discuss the most appropriate timing for a compliance review to consider the reinstatement of accredited official statistics status.

Yours sincerely

Ed Humpherson
Director General for OSR

Scott Heald to Ed Humpherson: Inpatient, day case and outpatient stage of treatment compliance review: PHS Actions

Dear Siobhan,

Thank you for carrying out the helpful compliance review of the PHS Stage of Treatment statistics. I was delighted that these statistics retained the accredited official statistics status following my team’s work to develop their trustworthiness, value and quality in 2025. I particularly welcome your acknowledgement of our work to ensure the changes to improve the statistics’ relevance and timeliness was conducted transparently and with integrity.

We have made the following changes in response to OSR’s recommendations to enhance users’ understanding of the statistics:

  • Provide more specific guidance about the comparability of waiting times statistics pre and post guidance implementation and more prominent advice about the risks of adding waiting lists together
    • The 28th April publication (based on data up to end of March 2026) will include an updated version of the PHS Impact Assessment (first published in October 2025) incorporating data up to the end of March 2026. Our commentary will be clearer about the size of the change for each of the key metrics and we will refer to this in the monthly report published in April and in future releases where applicable.
    • The 3rd February 2026 monthly publication (based on data up to end of December 2025) reinstated our advice (highlighted in bold) that the number of ongoing waits inpatients, day cases, new outpatients and any other service (e.g. diagnostics) should not be added together to determine the proportion of the total population waiting for these types of care. This warning will be included in future monthly releases and we will proactively engage with users who use the statistics in this way.
  • Explain how these statistics relate to similar measures across the UK
    • The 28th April publication (based on data up to end of March 2026) will identify and summarise key messages from the existing work published by ONS on UK health statistics’ comparability. These insights will continue to be included in future monthly releases. We will also engage with UK contacts and groups to identify other information that we could provide to help users understand what data can and can’t be compared across the UK.

The review also highlighted the need to record and publish details of the full list of roles receiving pre-release access (PRA), review the list regularly and ensure PRA is justified, proportionate and minimised. We work with colleagues in Scottish Government and NHS Boards to coordinate the PRA process and have not, to date, experienced issues arising from misuse or early reporting of information provided via PRA. I share OSR’s commitment to ensuring the PRA process is transparent and robust and have taken the steps outlined below to enhance our approach.

  • From today, the PHS website’s about our statistics page has a new pre-release access transparency section listing the roles that require PRA to all PHS statistics releases as well as those who require PRA to the Stage of Treatment release.
  • As the weeks progress, we will continue to update this new section with PRA details for all other PHS statistics releases.
  • I have reviewed the SoT PRA list and the list of roles who receive PRA for all PHS releases. I am assured that the roles named in those are justified, proportionate and we are appropriately minimising the risk of leaks and disorderly publication. I will of course continue to monitor these lists as we publish them going forward for all other releases.

I am copying this letter to Alistair McAlpine, Scottish Government Chief Statistician and Anita Morrison and Nicola Edge, Heads of Health and Social Care Analysis, Scottish Government, whose teams work with PHS to manage the PRA process and are supporting us to implement the changes outlined above.

Yours sincerely,

Scott Heald

Director, Data and Digital Innovation

Head of Profession for Statistics

Related links: Compliance review of inpatient, day case and outpatient stage of treatment waiting times produced by Public Health Scotland  – Office for Statistics Regulation

Siobhan Tuohy-Smith to Scott Heald: Compliance review of inpatient, day case and outpatient waiting times statistics – Office for Statistics Regulation 

Siobhan Tuohy-Smith to Scott Heald: Compliance review of inpatient, day case and outpatient waiting times statistics

Dear Scott,

We have completed a compliance review of Public Health Scotland (PHS)’s statistics on inpatient, day case and outpatient stage of treatment waiting times against the standards of the Code of Practice for Statistics. The review considered whether these statistics continue to meet the standards of Trustworthiness, Quality and Value and should retain their accredited official statistics status.

Based on the findings of the review, we conclude that the statistics continue to comply with the Code and should retain their accredited official statistics designation. We welcome the improvements that PHS has made, including the move to monthly reporting and the transparent implementation of revised waiting time definitions. The review also identifies a small number of areas where further action is needed, particularly around supporting users to understand comparability over time, clarifying how these statistics relate to similar measures across the UK, and strengthening transparency and central control over pre-release access.

We note that PHS is already progressing work to ensure full compliance with the updated Code of Practice for Statistics (Code 3.0), and we welcome the commitment to embed these requirements as part of ongoing development of the statistics.

I am grateful for the constructive engagement from your team throughout the review and look forward to receiving an update on progress against the recommendations.

I am copying this letter to Mairi Watson, Information Consultant for Planned Care Waiting Times Analytical Team.

Yours sincerely,

Siobhan Tuohy‑Smith
Assessment Programme Lead
Office for Statistics Regulation

Related:

Letter from Scott Heald to Ed Humpherson: NHS stage of treatment waiting times statistics  

Letter from Scott Heald to Ed Humpherson: NHS diagnostics activity and stage of treatment waiting times statistics   

Letter from Ed Humpherson to Scott Heald: NHS diagnostic activity and stage of treatment waiting times statistics   

Rob Kent-Smith to Sean Whellams: Compliance review of direct effects of illustrative tax changes bulletin

Dear Sean

Direct effects of illustrative tax changes bulletin – compliance review

We have completed our compliance review of HMRC’s Direct effects of illustrative tax changes bulletin. While the bulletin is clear and well signposted, it is based on economic modelling rather than observed data, raising questions about its classification as official statistics.

To strengthen transparency and value, we recommend that HMRC:

  • Publish a fuller methodology and further explain model assumptions and uncertainties.
  • Provide additional guidance on appropriate use of estimates.
  • Engage users regularly to inform improvements.
  • Consider whether the “official statistics” label remains appropriate.

We expect these points to be addressed in the spring 2026 update and will continue to engage with you on next steps.

Thank you for your cooperation on this.

Yours sincerely

Rob Kent-Smith

Deputy Head of the Office for Statistics Regulation

Related

Compliance review of Direct effects of illustrative tax changes bulletin

Ed Humpherson to Scott Heald: Assessment of NHS Education Scotland’s workforce statistics

Dear Scott,

Assessment of NHS Education Scotland’s workforce statistics

We have completed our assessment of statistics about the NHS workforce in Scotland produced by NHS Education Scotland (NES): Workforce statistics, CAMHS Workforce statistics and Psychology Workforce statistics. I am grateful for the positive contribution and engagement from the team at NES throughout the assessment process.

As you know, we began an assessment of NHS workforce statistics in 2022, following the change in producer organisation from Public Health Scotland (PHS) to NES. Our early investigations identified that further work was required to ensure that the statistics fully complied with the Code of Practice for Statistics (the Code) so we agreed with you to temporarily pause the assessment process at that time.

Last year your team wrote to me to explain that NES had made substantial progress and was ready to restart the assessment. We restarted our assessment in January 2025. We found that NES has made good progress in its compliance with the Code of Practice for Statistics (the Code). NES has improved its governance processes, engages well with users and improved its published information on quality and methodology.

We have identified six requirements to help strengthen the statistics further, to ensure that they fulfil the expectations of the Code. These focus on publishing statistical policies and governance procedures, reviewing the pre-release access lists, publishing a user engagement strategy, publishing more information on cross-UK comparability, improving the presentation of the statistics (including the coherence of data definitions), and clearly setting out reasons for methods choices.

We judge that the statistics about the NHS workforce in Scotland can be designated as accredited official statistics once we have confirmed that the requirements set out in the report have been met. Addressing the requirements will demonstrate that statistics about the NHS workforce in Scotland meet the highest standards of trustworthiness, quality and public value and comply with the Code. We have agreed with NES that it should meet these requirements within six months and keep us updated on progress.

I am copying this letter to Colin Tilley, lead official at NES.

Yours sincerely

Ed Humpherson
Director General for OSR

Related

Compliance review of statistics about the NHS workforce in Scotland

Scott Heald to Ed Humpherson: Request for Assessment of the NHS Scotland workforce statistics (February 2022)

Ed Humpherson to Scott Heald: Assessment of the NHS Scotland workforce statistics (February 2022)

Mark Pont to Scott Heald: Assessment of the NHS Scotland workforce statistics (August 2022)

Catherine Bromley to Ed Humpherson: Request to re-start assessment of the NHS Scotland workforce statistics (March 2024)

Ed Humpherson to Catherine Bromley: Request to re-start assessment of the NHS Scotland workforce statistics (March 2024)

Rob Kent-Smith to Grant Fitzner: Compliance review of CPI and CPIH statistics

Dear Grant,

Compliance review of CPI and CPIH statistics

We have completed our compliance review of the Consumer Prices Index (CPI) and the Consumer Prices Index including owner occupiers’ housing costs (CPIH) statistics against the Code of Practice for Statistics. Our review looked at how ONS is handling its transformation programme for the consumer price statistics, especially in terms of the Quality and Value pillars of the Code.

Based on the findings of the review, it is our view that, overall, the transformation programme is meeting user needs and improves on current measures. We have seen evidence of assured quality and that the new data and methods are sound and suitable. However, the review makes four recommendations for ONS to address to further support the transformation of these statistics.

The statistics retain their status as accredited official statistics. Given the significance of the changes to consumer price statistics, we have previously noted our intention to re-assess CPI and CPIH once grocery scanner data have been incorporated and embedded. Our decision to re-assess is not in response to any specific concerns about the quality of CPI or CPIH but instead seeks to ensure that we provide appropriate regulatory oversight for these key statistics following a period of significant development.

I am grateful for the positive engagement from your team throughout the review.

I am copying this letter to Michael Hardie, Deputy Director, Prices Transformation; Stephen Burgess, Deputy Director, Prices Production; and Chris Payne, Assistant Deputy Director, Head of Consumer Prices Strategy and Resilience.

Yours sincerely,

Rob Kent-Smith

Deputy Head of the Office for Statistics Regulation

Siobhan Tuohy-Smith to Stephanie Howarth: Compliance review of maternity and births statistics and breastfeeding statistics

Dear Stephanie,

We recently completed a compliance review of Welsh Government’s Maternity and births statistics and Breastfeeding statistics against the standards of the Code of Practice for Statistics. Our review considered whether the Welsh Government can continue to publish the statistics as accredited official statistics. 

Based on the findings of the review, it is our view that the statistics comply with the standards of trustworthiness, quality and value in the Code and should retain their accredited official statistics status. We make three recommendations for enhancing the quality and value of the statistics.  

I am grateful for the positive engagement from your team throughout the review. 

I am copying this letter to Annie Campbell, Head of Population and Community Health Statistics. 

Yours sincerely,

Siobhan Tuohy-Smith 

Assessment Programme Lead 

Related Links:

Compliance review of maternity and births statistics and breastfeeding statistics