UK Statistical System UK Statistics Authority Code of Practice
Compliance check

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

Ed Humpherson to Eugene Mooney: Temporary suspension of accredited official statistics status of the Northern Ireland Ambulance Service (NIAS) ambulance statistics within the Northern Ireland Hospital Statistics: Urgent and Emergency Care publication

Dear Eugene

Thank you for your letter regarding the Northern Ireland Hospital Statistics: Urgent and Emergency Care publication, and the change to the data source for ambulance service data.

Given the fact that you have not yet been able to fully familiarise yourself with the new data for the ambulance response times and assure yourself of its quality, I agree to your request to temporarily suspend the accreditation of the NIAS sourced data contained within the Northern Ireland Hospital Statistics: Urgent and Emergency Care publication. This suspension should also apply to previous releases impacted by this quality concern and a notice published explaining to users the concerns you have and the work you are doing to investigate these issues.

I note that you plan to carry out a Quality Assurance of Administrative Data (QAAD) exercise, and there is useful guidance on our website to assist you with this. I also note that you intend to label this part of the statistical release official statistics in development. We have published Official Statistics in Development guidance to help producers understand when and how to use this label.

My team will be happy to liaise with you about the most appropriate timing for a review of the Northern Ireland Hospital Statistics. This will take place once you have completed your review and are assured that the statistics can meet the standards expected by the Code of Practice for Statistics.

Yours sincerely

Ed Humpherson
Director General for Regulation

Related Links: Eugene Mooney to Ed Humpherson: Temporary suspension of accredited official statistics status of the NIAS ambulance statistics within the Northern Ireland Hospital Statistics: Urgent and Emergency Care publication. – Office for Statistics Regulation

Alastair McAlpine to Ed Humpherson: Developing a modern statistical system – A review of Scotland’s Census 2022 – progress in meeting recommendations

Dear Ed,

In February, I wrote to you to let you know that our internal review of the Census had been published. This included four recommendations focussed on learning for the future delivery of strategically important statistical exercises across the Scottish Statistical System.

I have appreciated your support for this work and the recognition of my commitment to assure that leadership and statistical decisions in Scotland are made with appropriate oversight and seniority.

I am therefore writing to set out more detail on how I intend to meet the recommendations and the progress that has been made to date. Focus over the first three months has been on recommendation one with actions also initiated on recommendations two and four, as described in the table below. Work on recommendation three will commence in the latter half of 2025 building on the actions delivered.

RecommendationProgress to dateFuture plans
1. The Chief Statistician should consider activities including a task and finish group to define and identify the ‘Cross-cutting Statistical Components’ of the Scottish Statistical system and other projects.A small task and finish group was set up in March 2025 with representation from across Scottish Government analytical areas. The group produced proposed criteria and an initial list of cross-cutting statistical components which it presented to me in April.The criteria and list of components will be tested with senior statisticians and the Analytical Leadership Group, and the Scotstat Board will be kept informed. Once finalised the list of components will be published on our website and reviewed annually. We will share the list with OSR in a future update.
2. The Chief Statistician should consider opportunities to enable planning and training for the wider statistical profession to be linked to the broader skills needed for the delivery of cross-cutting statistical components by different organisations across the Scottish statistical system.A successful programme of leadership training is already being rolled out to B3 and C1 statisticians – ‘Fit for the Future’. I have tasked my team to explore options for similar development opportunities at C2 level and determining the skills needed at this grade. We have opened discussions with senior statisticians.Discussions with senior statisticians will inform our leadership training offer. Further information will be provided in my next update.
3. The Chief Statistician should consider what mechanisms are required to provide oversight and assurance of cross-cutting statistical components in a holistic way and escalation of key decisions that could impact an integrated statistical system.Prior to this review, the Office of the Chief Statistician had already been restructured to centralise professional functions and support. This work will improve the function that OCS provides on assurance.to the Chief Statistician. Draft guidance on assurance of topical and cross-cutting statistical matters has been developed.Now that a list of critical statistical components has been developed and statistical assurance guidance drafted, we will review it with senior statisticians and the Analytical Leadership Group, keeping the Scotstat Board informed. This will be a focus of our response to the review over the remainder of the current financial year.

I expect these planned actions to support the modernisation of our statistics, build trust and improve the transparency in our statistical decisions and methods.

I am copying this letter to the Minister for Parliamentary Business who has responsibility for statistics within his portfolio, Alison Byrne Chief executive of the National Records of Scotland, Scott Heald of Public Health Scotland, and the co-chairs of the Scotstat Board.

Yours sincerely,

Alastair McAlpine
Chief Statistician

Scott Heald to Ed Humpherson: Temporary suspension of accredited official statistics status of cervical cancer screening statistics

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

 

Related links: 

 

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.

Siobhan Tuohy Smith to Elaine Drennan: Compliance review of disability payment statistics produced by Social Security Scotland

Dear Elaine  

We recently completed a compliance check of Social Security Scotland’s Adult Disability Payment and Child Disability Payment statistics, which are both published as official statistics in development. To support their further development, we have carried out a high-level investigation into whether the statistics are being improved in line with the Code of Practice for Statistics. In this letter, we outline our findings and improvements to consider as your team continues its work on these statistics. 

These statistics show information on applications and payments for child and adult disability payments. The main messages from the statistics are clearly explained, with appropriate commentary. Suitable charts and tables are used to illustrate the statistics. We judge that the statistics are presented impartially and have been released in an orderly manner, in line with the Scottish Government’s statistics publication timetable. To inform users of any changes to past data, the outputs include a description of the revisions made. 

Suitable data sources are used to compile the statistics, and the team is planning to further improve how it explains the limitations of the data. The statistics are sourced from the person-level dataset held in Social Security Scotland’s own internal case management system. The data are extracted and securely transferred to the statistics team. There is some information published on the limitations arising from the methods used to compile the statistics, including bias and uncertainty. The statistics team told OSR that it is planning to publish more information about uncertainty in the data, potential biases and the resulting impact on the statistics, which is good practice. 

Currently, part of the data processing is manual, and the statistics team told OSR that it is in the middle of transferring to an automated statistics production pipeline. The plans to automate the data processing process are in line with good practice and should improve the quality of the statistics. Once the transition to automation is complete, Social Security Scotland should publish detailed information about the new quality assurance steps and stages. It should also consider publishing the software code used to produce the statistics. 

Engaging with users to understand their needs will enable Social Security Scotland to consider and prioritise developments in line with user need. The statistics team indicated that it is engaging with a range of users in central government, local government and the NHS. We also welcome the fact that users approach the statistics team in an ad hoc way and that the team asks for feedback to gather insight on how to develop the statistics. 

To further enhance the Trustworthiness, Quality and Value of these statistics, we have identified the following improvements for your team to consider: 

  • To provide users with a wider view of the disability benefits landscape, Social Security Scotland should consider providing information about other UK disability payments statistics in the release and commenting on how the statistics should or should not be compared. 
  • Publishing more detail about the quality assurance processes would provide greater assurance to users. For example, Social Security Scotland should include a process map, identify potential sources of bias and error, and describe the actions taken to minimise risks to data quality. 
  • It would help potential new users if Social Security Scotland published more information about its statistics user engagement plans, so that users know that it are willing to hear their views. 
  • To support the development of these statistics, and in line with our guidance about official statistics in development, Social Security Scotland should consider publishing more detail about its plans to develop these statistics, including timelines and how users will be involved the process. 

I would like to thank your team for its positive engagement with us during this review. We will continue to engage with you as you develop these statistics. Once you consider that these statistics, or other statistics in your portfolio, are ready for a full assessment against the Code, please do not hesitate to get in touch. 

I am copying this letter to Alastair McAlpine, Chief Statistician of the Scottish Government. 

 

Yours sincerely 

Siobhan Tuohy-Smith 

Assessment Programme Lead

Related Links:

Letter: Ed Humpherson to David Wallace: Transparency and user engagement in the production of official statistics

 

Siobhan Tuohy-Smith to Stephanie Howarth: Statistics on Council Tax in Wales

Dear Stephanie 

We recently completed a compliance check of council tax statistics produced by the Welsh Government against the Code of Practice for Statistics. We completed this review as part of a series of compliance checks on council tax statistics produced in Great Britain (GB). The scope of this review included the annual dwellings, levels and collection rates outputs. These statistics are valuable to users who are trying to understand how council tax affects them. Furthermore, these statistics help the public hold the Welsh Government to account by keeping a public record of the current condition of the Welsh council tax system. The statistics also have considerable potential value in helping to inform public debate around planned changes to Welsh council tax policy, property revaluation and bandings. 

Our review found a mixture of positive practices and areas where the statistics could be improved. From our engagement with your statisticians, we are assured of the quality of the statistics. They are largely based on financial information from audited local government accounts, and there is a comprehensive approach to quality-assuring the incoming data. Your team has also committed to improve the presentation and value of the statistics as part of its plans to improve their accessibility by publishing each bulletin in HTML format in the first half of 2025. We have therefore concluded that the statistics should retain their accredited official statistics status.  

We found helpful information about the high 100% response rate from local authorities in each publication, and the comprehensive list of quality assurance checks performed on the incoming data helps to reassure users about your approach to quality management and understand the quality of the statistics. It is also good that if quality issues are identified during data validation, these are communicated to the data provider and the issues can be rectified. Furthermore, using automatic data validation and feedback mechanisms helps to ensure data quality and improves the efficiency of the production process. We also commend the use of RAP principles and encourage the team to be transparent about this to demonstrate the quality of the statistics.  

We welcome your team’s commitment to improve the presentation and value of the statistics. The statistics are published as PDF summaries and contain a variety of breakdowns and supporting commentary. The statistics are also available via StatsWales, which allows users to view a variety of customisable tables. The PDF summaries provide useful background information around how Welsh council tax works and charts are used effectively to demonstrate trends. We discussed with the team where including additional charts and commentary on key trends and the policy context in Wales could further highlight the relevance and value of these statistics for a broader range of users – for example, on the Welsh Government’s previous and planned changes to council tax policy. Including links between the summaries to other relevant content, such as the summary quality report, published pre-release access lists and data on StatsWales, would also make it easier for users to access this information from the statistics and further support their appropriate interpretation. We look forward to seeing these improvements for each publication, as part of your team’s plans to publish the statistics in HTML format, starting with the dwellings statistics in January 2025. 

The following paragraphs highlight other improvements that we consider would further enhance the trustworthiness, quality and value of the statistics. 

Helpful comparisons of council tax statistics between local authorities are included, but there should be more information on the extent of comparability of council tax statistics between GB nations. A comparison to council tax in England is made in the levels publication, though this should be reviewed before the next publication due to divergences between Wales and England council tax policy, including property revaluation in Wales in 2003, which was not replicated in England. This comparison will also become less viable should the Welsh council tax system change again in the next few years. We highlighted to the statistics team some recently published guidance by Scottish Government statisticians on the comparability of council tax statistics between GB nations. We encourage your team to engage with its counterparts in England and Scotland, to achieve consistent guidance to support users of council tax statistics across GB in making appropriate comparisons. 

While we understand there is no sampling error due to the 100% return from councils, uncertainty can arise in other ways. We recommend that the team investigate where potential sources of error and uncertainty in the administrative source data may exist and use this information to improve the communication of uncertainty in the statistics. The team may find our Quality Assurance of Administrative Data (QAAD) toolkit and Approaches to presenting uncertainty in the statistical system insight report useful to identify where potential uncertainty or bias may need to be communicated. In addition, the summary quality report covers multiple publications and appears outdated. In its current format, the information is quite general, which makes it hard for users to find more-specific quality information relating to individual publications. It should be reviewed to ensure users have current information on quality, to support an appropriate interpretation of the statistics. 

Finally, while the statistics include an email address for users to provide feedback, the team could more proactively seek to increase its understanding of users’ needs, so that the statistics remain relevant and useful. This will be especially important given planned changes to Welsh council tax policy and related developments to the statistics. We recommend that the team explicitly set out its approach to user engagement and proactively seek feedback on the changes made to the statistics, following their publication in HTML. 

I would like to thank your team for their positive engagement during this review. Our Housing, Planning and Local Services team has provided some detailed points of feedback to your statisticians on the presentation of statistics and will keep in touch with them as they take these recommendations forward. Please get in touch if you would like to discuss any aspects of this letter or if we can be of further assistance. I am copying this letter to Anthony Newby, the responsible statistician. 

 

Yours sincerely 

Siobhan Tuohy-Smith 

Assessment Programme Lead 

Mark Pont to Sandra Tudor: Compliance Check of Social Housing Lettings in England

Dear Sandra

Statistics on social housing lettings in England

We have recently completed a compliance check of your statistics on social housing lettings in England against the Code of Practice for Statistics. We found that these statistics are a good demonstration of how to produce and publish official statistics, and the statistics should keep its accredited official statistics status. Our review found a range of positive features that demonstrate the trustworthiness, quality and value of the statistics.

These statistics transparently show the availability of social housing lettings in England and the characteristics of those renting these dwellings. The statistics are presented in two separate bulletins on tenants and tenancies that include a variety of breakdowns and are presented in an accessible and informative way. We found a good balance of statistical content and commentary that will help users to interpret the statistics appropriately and understand what they show. For example, comparisons are made between social rent rates and private rent rates in different geographical locations.

The technical notes provided with the publication contain much information that helps users understand the strengths and limitations, which in turn supports the appropriate use of the statistics. For example, the information on the use of weighting and imputation for certain measures is accessible to both expert and non-expert users. This methodological information indicates the level of uncertainty in the statistics, enabling their appropriate use.

As well as the qualitative indications of uncertainty provided, the quantitative information on uncertainty given in the quality data tables is a fantastic resource for expert users who wish to use the statistics for analysis. Confidence intervals tables are presented for specific figures which are imputed, allowing users to understand the extent of missing data in CORE and how much has been imputed.

Between the 2022 and 2023 publications, you undertook a large amount of work to develop both the presentation of the statistics, and the CORE system. The improvement of presentation and accessibility is exemplary and has enhanced the usability of the statistics. Separating the statistics into bulletins on tenants and tenancies allows more space for interesting analysis on each topic area in an accessible way. Furthermore, the statistics are easier to navigate, and a clear distinction is made between the statistics on tenancies and tenants, each of which has distinct uses.

We were also told by the statistical team that there have been improvements to efficiency and quality assurance because of these recent developments. Question routing and inference is now possible, which has reduced respondent burden for existing tenants, as questions can be skipped in appropriate circumstances and information from previously completed fields can be carried forwards. The improvements to the CORE data collection, have made it cheaper to run and less dependent on experts, showing your commitment to ensuring value for money and efficiency. The team also told us that it plans to carry out quality assurance of LA data submissions mid-year, allowing for quality issues to be caught early.

Your plans to set up an ad hoc requests database that will bring together data from different types of information requests, including direct ad hoc analysis requests and those made through FOIs, will provide a better overall user experience. Constructing this as a database will reduce the number of repeat requests for information; improve efficiency by limiting the need to recompile information; and ensure that previous information is not lost.

To further enhance the trustworthiness, quality and value of these statistics, we have identified ways the statistics and their presentation could be improved:

  • Though the communication of uncertainty in the technical notes is excellent, the communication of uncertainty within the tenants and tenancies bulletins could be improved. It could be clearer that the quoted figures are estimates with varying degrees of uncertainty. Communicating the level of uncertainty in the statistical bulletins will help to ensure an accurate interpretation of the statistics.
  • It would help potential new users if you more explicitly communicated your approach to user engagement, so people know how to get in touch and that you are open to hearing their views. Proactively engaging with external users will allow the statistical team to gather feedback from a broader range of sources and facilitate an ongoing dialogue around the further development of the statistics.
  • Providing more links between the different social lettings outputs, for example, to the data tables and technical notes in the bulletins, would enhance the accessibility of the full range of outputs for users.

I would like to thank your team for its positive engagement during this review. We recommend the team looks for opportunities to champion the value of the recent developments, for example, through the publication page itself, and through cross-government channels such as the GSS housing and planning steering and working groups. Please get in touch if you would like to discuss any aspects of this letter. I am copying this letter to Richard Field, Head of Housing and Planning Statistics, MHCLG; and Rachel Worledge, Lead Statistician, CORE Social Housing, MHCLG.

Yours sincerely

Mark Pont