On Tuesday 8 July, Sir Robert Chote, Chair of the UK Statistics Authority, Emma Rourke, Acting National Statistician and Ed Humpherson, Director General for Regulation, gave evidence to the Public Administration and Constitutional Affairs Committee’s inquiry on the work of the UK Statistics Authority.
A transcript of which has been published on the UK Parliament website.
On Thursday 26 June 2025, Jen Woolford, Director for Public Policy Analysis gave oral evidence to the Lords Social Mobility Policy Committee for their inquiry into social mobility.
A transcript of the session is available on the UK Parliament website.
Dear Simon
I am writing in response to the call for evidence for the Committee’s inquiry into the work of the UK Statistics Authority. We welcome our regular appearances before the Committee, not just as a channel of formal accountability to Parliament, but also as an important source of support, challenge and advice in ensuring that the official statistical system serves the public good as effectively as possible.
Last week, the Authority announced the resignation of Sir Ian Diamond as the UK’s National Statistician due to ongoing health issues. I am grateful to Sir Ian for his tireless energy and the passionate dedication he brought both to the role of National Statistician and to championing the vital role of statistics across society more broadly. Sir Ian oversaw many successes over his tenure during a remarkable period of economic and societal change, particularly during the pandemic. Emma Rourke, Deputy National Statistician for Health, Population and Methods, will be Acting National Statistician pending longer term arrangements being put in place. We will keep your Committee updated on these arrangements.
As you will be aware, it has been a challenging period for the official statistical system and for the Office for National Statistics (ONS) in particular. Most obviously, the long-term trend of declining response rates for household surveys accelerated following the Covid pandemic, making it more difficult and expensive to maintain the quality of key economic data on which policy and other decision makers rely – most notably those relating to the labour market. T his has happened at a time when financial resources remain constrained and the barriers within government to the sharing, linking and exploitation of administrative data remain frustratingly high.
Colleagues across the official system have worked tirelessly to address these challenges and to exploit available opportunities, and the ONS and other statistical producers have continued to generate many high-quality outputs. But we need to ensure that the system is focused on addressing the challenges and difficulties, as well as being self-critical and open to learning and advice from outside when things can be done better. To that end, in addition to benefiting from the insights of the Lievesley Review in 2024, the UK Statistics Authority Board has supported the ONS in commissioning an unsparing internal ‘lessons learned’ exercise around the process of reforming its labour market statistics, in drawing on technical input from independent outside experts, and in engaging with and responding fully to the recommendations and requirements of the Office for Statistics Regulation (OSR).
Most recently, in April 2025, the Board and the Cabinet Office jointly commissioned Sir Robert Devereux to undertake a short but wide-ranging independent review of the performance and culture of the ONS, drawing on the experiences and insights of staff across the organisation as well as external stakeholders. As I write this letter, the review is still under way. But I am confident that it will provide important insights and recommendations to help ensure that the ONS can operate to its full potential, and we will be able to brief you on these at a later stage of your inquiry.
You set out four sets of questions in your Terms of Reference:
To address these questions, I attach three submissions – one each from the Authority, the OSR and the ONS. As you will appreciate, the ONS is in a period of transition following the resignation of Sir Ian Diamond as National Statistician on 9 May 2025 and the ONS submission was being written as he departed.
We look forward to discussing the questions you have raised and any other issues with you and the Committee on 1 July.
Yours sincerely,
Sir Robert Chote
Chair, UK Statistics Authority
How does the UK Statistics Authority Board carry out its statutory functions, and how involved is it in the decisions taken by senior leaders at Office for National Statistics (ONS) and the Office for Statistics Regulation (OSR)?
Introduction
The UK Statistics Authority was established under the Statistics and Registration Service Act 2007 (‘the Act’) and formally assumed its powers under the Act on 1 April 2008. The Act gave the Authority the statutory objective of ‘promoting and safeguarding the production and publication of official statistics that serve the public good’. The public good includes:
In practice the Authority fulfils these objectives directly through the Office for National Statistics (ONS; its executive arm and the largest single producer of official statistics in the UK) and the Office for Statistics Regulation (OSR; its assessment arm), and indirectly through its oversight of the Government Statistical Service (GSS; the statisticians working in UK and devolved government departments and public bodies, which produce most UK official statistics)
The governance of the Authority was examined by Professor Denise Lievesley in her independent Review of the UK Statistics Authority (‘Lievesley Review’) published in 2024. The Authority welcomed Professor Lievesley’s recognition that the Authority’s governance was working well and that the two executive arms (the ONS and OSR) are sufficiently operationally independent in practice. To increase public understanding of the de facto distinction between the arms of the Authority, OSR published a statement on the operational separation between the ONS and OSR in October 2024.
Membership of the Authority Board comprises the Chair, at least five non-executive members, and three executive members. Other members of the ONS and OSR executive staff and representatives of the GSS attend as required.
As detailed in the standing orders of the Act, the Board is required to ‘usually to meet at least eight times a year’, but in both 2023 and 2024 met ten times. It also holds ad hoc meetings to cover topics of interest in greater depth or when more timely input is needed. The Chair has regular separate bilateral meetings with the National Statistician and the head of OSR, and non-executive members meet with ONS and OSR staff as needed on topics of shared interest or expertise.
The Board delegates some of its functions to committees. Among them, the Regulation Committee oversees the work of OSR, inputting to and signing off its major reports and decisions. As OSR regulates the ONS as well as other statistical producers, to avoid conflicts of interest as far as possible, the Regulation Committee comprises non-executive members of the Board and OSR executive members, but no executive staff from the ONS.
The Authority’s engagement with the devolved administrations is guided by the Concordat on Statistics, an agreed framework for co-operation in relation to the production of statistics, for and within the UK, statistical standards and the statistics profession. High-level governance and oversight of cross-UK statistical work is provided by the Authority’s Inter-Administration Committee (IAC), chaired by the National Statistician with membership including the Chief Statisticians of the devolved administrations.
Statutory functions
The functions of the Authority under the 2007 Act include:
In common with other public and private sector organisations, the Act imposes a duty on the Board to produce a report after the end of each financial year: the Authority’s Annual Report and Accounts. This meets statutory obligations, providing transparency and accountability for the use of public resources. The most recent Report (for 2023/24) can be found on the Authority website.
The Board must exercise its functions efficiently and cost-effectively and seek to minimise the burdens it places on other persons.
The Board and decision making
As noted above, the Board comprises a combination of executive and non-executive members. The non-executive members are appointed by ministers on the recommendation of an appointment panel that typically includes the Authority Chair, an independent member, and a representative from the Cabinet Office as sponsor department. The aim is to ensure a range of skills and expertise, currently from academia, public service and the private sector. Individual members’ expertise currently encompasses economics, statistics, data collection, technology, risk and governance and communication.
In the last couple of years, it has been something of a struggle to maintain a full complement of non-executive members despite excellent candidates being available. The previous Government refused to renew members beyond their initial three-year term (contrary to good governance practice which would have allowed at least one additional term) and it took a significant period to complete the appointment process for our three most recent arrivals as the process was delayed by the general election. Despite periods of sitting without a full quota of non-executive members, Board meetings were able to be quorate on virtually every occasion, and members in post continued to be actively engaged with the work of the Authority holding relevant expertise.
Board meetings typically comprise regular reports from the Chair, National Statistician, head of OSR, head of communications and sub-committee chairs, plus papers on substantive items of current importance. Some of these are on a regular cycle (for example discussion of business plans and the annual report and accounts). Some are as needed. In the last couple of years, regular items have included labour market statistics, the Integrated Data Service and the future of population statistics (including the census). On occasion, regular issues of this sort are dealt with through discussion of the National Statistician’s report to avoid staff working in high pressure areas spending too much time preparing board papers rather than on their core activities.
Agenda papers may ask the Board to note particular developments, to offer advice or to make formal decisions – for example endorse a recommendation from the National Statistician on the future of population statistics or the need for a census. As detailed in Section 30 of the Act, the National Statistician is the Board’s principal adviser on the quality of official statistics, good practice in relation to official statistics and the comprehensiveness of official statistics. The Board must have regard to their advice on those matters. Decisions are normally made following discussion that leads to a shared view of the way forward. However, the Chair can request a formal vote with a simple majority of those present deciding the matter. The Board has not yet voted formally.
The Board sets the broad direction of the Authority through agreement on a five-year strategy, currently Statistics for the Public Good 2020-2025 and due to be refreshed this year. The ONS and OSR business plans underpin delivery of the strategy, and the Board is engaged in the development of these, providing support, oversight, scrutiny and challenge ahead of approval.
The Board and its committees periodically review their own effectiveness and the effectiveness of their members. In line with good practice, we will be commissioning an externally led review of the Board in the coming year.
Subcommittees of the Board
Regulation Committee
The role of the Regulation Committee (formerly the ‘Assessment Committee’) is to help shape the regulation strategy of the Authority and to oversee the programme of assessment of sets of official statistics against the Code of Practice for Official Statistics, plus other work related to assessment and regulation, thereby contributing to achievement of the Authority’s strategic objectives.
In practice, this means overseeing the work of OSR in setting, promoting and judging compliance with the Code, and in intervening (via the Authority Chair, the head of OSR or other OSR staff) when ministers, senior public figures or statistical producers fall short of the code or the associated principles of ‘intelligent transparency’. Committee members consider the final conclusions of assessment reports ahead of publication and also support the OSR in its wider activity aimed at supporting good practice.
The OSR’s recent work is described in detail in OSR’s submission. Recent areas of regulatory focus have included labour market statistics, specific economic statistics, the broader landscape of economic statistics, population statistics and the approach to gender identity in the last census. On a number of occasions, the Regulation Committee has de-accredited official statistics that no longer comply with the Code (sometimes at the producer’s request), accompanied by agreement on actions that, if fulfilled, would allow the statistic to be re-accredited as Code-compliant.
The Regulation Committee meets at least quarterly, with additional meetings convened as necessary. It comprises the Authority Chair, three non-executive Members of the Board and the head of OSR, with other OSR staff members attending as required. There are no executive staff members from the ONS or other statistical producers represented on the committee (except when invited as guests for specific discussions), consistent with the statutory requirement to separate statistical production and assessment.
The Audit and Risk Committee
Executive accountability for risk management resides with the National Statistician (as Accounting Officer), with executive oversight residing with the Executive Committee and its sub-committees. Chaired by a qualified Non-Executive Member, the Audit and Risk Assurance Committee (ARAC) supports the Board and the Accounting Officer in their responsibilities for risk management, control and governance by reviewing the comprehensiveness, reliability and integrity of the assurance available to them.
The Authority Risk and Assurance Framework provides a mechanism for the identification, analysis and management of risks across the Authority and is aligned to The Orange Book – Management of Risk, and reflects Risk Management best practice.
ARAC has responsibility for advising the Board on the effectiveness of governance, risk management and the system of internal control. This is also informed through audits and advisory work by the internal audit team. It currently comprises of the Non-Executive Chair, two non-executive Board members, two external independent members.
The Authority Board ensures that plans are in place for any risks outside of appetite. Updates are provided to each ARAC meeting on the evolving profile. ARAC scrutinises the management of the strategic risks to satisfy itself that major risks are identified and that mitigation strategies and appropriate levels of assurance are in place. It challenges and holds the Risk and Assurance team and Strategic Risk Owners to account.
Currently the Authority’s Strategic Risks relate to:
Discussions by ARAC and the Authority Board have focused on the most significant risks to the successful delivery of the Authority strategy, including the interplay across the strategic risk profile, specifically statistical quality, technological resilience (with particular focus on legacy) and people and skills. The Statistics Quality risk has remained outside of appetite for a prolonged period. ARAC has provided a high level of oversight and consistently sought assurances on timing for the Statistics Quality risk to return within appetite. ARAC has also continued its focus on assuring legacy plans which should support improving quality and will play a key role in scrutinising all the strategic risks under the new risk profile, with particular focus on the quality of our economic statistics, legacy, people and meeting user needs.
Remuneration Committee
The Remuneration Committee agrees the pay and performance management framework for members of the Senior Civil Service employed by the Authority, within the parameters set by the Cabinet Office. It signs off performance and bonus decisions for staff at Deputy Director level and above.
How involved is the Board in the decisions taken by senior leaders at ONS and OSR?
As with most corporate or public sector organisations, a key role of the Board – and its non-executive members in particular – is to provide support and challenge to the Executive to help them deliver on the Board’s strategy and fulfil any statutory or regulatory duties. The Authority Board is unusual in that it has two executive arms – the production arm, the ONS, and the regulatory arm, OSR – and one of them regulates the other (along with the many other bodies producing official statistics). It also has a less direct responsibility for the GSS.
Within the ONS, the National Statistics Executive Group (NSEG) is the most senior executive committee, chaired by the National Statistician. Its role is to advise the National Statistician in the exercise of their functions as the Head of the GSS and Analysis Function and Chief Executive of the Authority. NSEG focuses on system-wide statistical and analytical matters, and this is reflected in the Group’s membership which includes two GSS Heads of Profession and colleagues from the devolved administrations. Meanwhile the Executive Committee (ExCo) focuses on all aspects of our business delivery within the ONS. Below NSEG and ExCo are a number of sub-committees that feed into discussions. For the OSR, the Regulation Committee helps to shape the regulation strategy of the Authority and oversee regulatory work. The Director General sits on the Regulation Committee, and he is supported by the OSR senior leadership team, who all attend the Committee.
Support and challenge from the Board is provided through multiple channels and is provided without seeking to conduct the role of the executive or micromanage. At every Board meeting there are update reports from the National Statistician and the DG for Regulation providing the opportunity for the two executive arms of the Authority to report on delivery against their respective Business Plans, including areas of success as well as highlight challenges. This allows the Board to engage, offer support, share expertise and offer challenge in the wider work of the executive arms, often covering work areas not discussed as substantive agenda items. When it is necessary to offer challenge, Board members are conscious of the need to be robust, forthright and persistent, while acting in a constructive and collegiate way and recognising any constraints the executive faces.
For support and challenge to operate effectively it is important that the executive has an accurate picture of what is going on the organisation and its major programmes and activities, and that this in turn is shared with the Board in a full and transparent way. As in almost every Board, the non-executives periodically emphasise the importance of candour and transparency so that they do not receive an incomplete or unduly rose-tinted picture.
The Chairs of the Audit and Risk, Regulation and Remuneration Committees also provide updates at the Board on the work of respective committees, in line with their delegated authority as set out in committee Terms of Reference. Through these updates the Board can share its views and support the work of Committees. For example, highlighting areas of concern and interest relating to Gender Identity in the 2021 England and Wales Census as the Regulation Committee investigated the matter.
The Authority Board receives monthly management information which helps to monitor performance against key deliverables as outlined in the Business Plan.
The Board sets the risk appetite for the Authority’s strategic risk profile and has a specific item on the strategic risks every six months. Work areas, projects and programmes feeding into strategic risks are of course often covered in substantive agenda items. This is underpinned by the work delegated to the ARAC. The strategic risk profile demonstrates the most significant risks to the successful delivery of the work of Authority Strategy. The forward agenda for the Authority Board reflects the key challenges and aligns to the strategic risk profile. The Board forward agenda is produced by the Secretariat in accordance with any determination of the Board and in consultation with the Chair of the Authority, the National Statistician and the Strategy and Policy Deputy Director.
External assurance
The Authority is unusual in that it has an in-house regulatory arm (OSR), which in addition to the work of the internal audit team, gives the Authority both internal and external scrutiny. Both the external and internal scrutiny are welcomed and encouraged by the Board.
External assurance is provided to the Authority Board and National Statistician in several ways. First and foremost, the Authority is an independent non-ministerial department that reports directly to the UK Parliament, the Scottish Parliament, the Welsh Parliament and the Northern Ireland Assembly. The work and interest of Parliamentarians and Committees, including the Public Administration and Constitutional Affairs Select Committee (PACAC), on the work of the Authority is an important source of support, challenge and advice in ensuring that the official statistical system serves the public good as effectively as possible.
In addition, the National Statistician has convened a set of advisory committees and panels to provide external independent advice on specific topic areas. They include
Membership of these groups includes representation from academia, government departments, the devolved governments and research bodies.
External expertise is also sought on a bespoke basis and shared with the Board. One such example was the review undertaken by Professors Ray Chambers and James Brown as part of the ONS’s systematic assessment of its readiness to manage the transition from the Labour Force Survey (LFS) to the Transformed Labour Force Survey (TLFS). They looked specifically at survey design, response patterns and weighting methods.
The Board also encourages frank and honest engagement with key users of ONS statistics to ensure that their requirements and feedback can be reflected. For example, ensuring that the ONS engages fully and constructively with the Bank of England and HM Treasury regarding the transition from the LFS to the TLFS and that any significant concerns they have are shared with the Board. The Stakeholder Advisory Panel on Labour Market Statistics chaired by Professor Jonathan Portes, and including representatives from other government departments, academia, the Scottish and Welsh governments and Northern Ireland Statistics and Research Agency has been a key source of advice and assurance as work on this transition has proceeded.
Over the last year this work has been an area of significant focus for the Board. The sharp fall in household survey response rates, a significant challenge in the UK as well as for other NSIs around the world has affected the quality of data from the LFS. As part of the work to address these challenges the ONS has been developing an online-first TLFS.
Throughout this process the Board has provided scrutiny, oversight, challenge and support as the has work progressed (as detailed in published Board papers). The non-executive members have also held extended sessions allowing them to better understand the range of issues. The Board has provided clear feedback about the risks of transferring from the LFS to the TLFS mindful of stakeholder concerns and quality issues. At their meeting on 27 March, the Board considered the advice by the National Statistician on the TLFS as well as assurances from technical advisors and the advisory committee to reach collective agreement on the way forward.
The National Infrastructure and Service Transformation Authority (NISTA) – previously the Infrastructure and Project Authority (IPA) – is the government’s centre of expertise for infrastructure and major projects. It regularly scrutinises any of our projects that fall under the Government Major Projects Portfolio (GMPP). These have included the ONS’s Integrated Data Service Programme and the Future of Population and Migration Statistics. Along with Treasury Business case reviews, these have offered external assurance both to the executive and the Board, although it is not unknown for projects that have cleared these hurdles multiple times to end up with difficulties that would presumably have been even harder for the Board alone to surface.
UK Statistics Authority
How successful has the OSR been in identifying issues with official data, and making the case for improvements?
Summary
The Office for Statistics Regulation (OSR) is charged with upholding the standards of official statistics across the UK. Through our wide-ranging regulatory work we identify issues and respond to stakeholder concerns about official data. We set requirements for improvements, as well as highlighting areas of best practice.
Our work has secured commitments from statistical producers that have led to positive improvements in many official statistics, although the speed with which this can be achieved is not always as timely as we would like. The importance of our role, and the independence and rigour that we bring to the task, has been noted by external reviews such as Professor Denise Lievesley’s independent review of the UK Statistics Authority and the PACAC report on Transforming the UK’s Evidence Base.
This submission sets out: our scope and approach to regulation; our key regulatory interventions and how we have identified issues and required improvements; and our views on the evolving statistical system. We have included clear examples of where our work has been vital in securing improvements or holding organisations to account against a backdrop of significant issues or concerns.
Many of the examples included in this submission relate to statistics produced by the Office for National Statistics (ONS). This represents some of our most recent and high-profile interventions. However, OSR’s regulatory activities span the range of Crown and non-Crown producers of official statistics across the UK.
Introduction
OSR is the regulatory arm of the UK Statistics Authority and was established in November 2016 following the Bean Review. OSR fulfils the assessment and regulatory function set out in the Statistics and Registration Service Act (2007). We are independent from Government and are separate from producers of statistics, including the ONS.
The work of OSR is overseen by the Regulation Committee of the UKSA Board, which comprises non-executive members of the main UKSA Board and the Director General of Regulation sits as an executive member. There are no executive members of the ONS on this committee to avoid any conflict of interest when OSR is examining the work of the ONS. The Chair of the Authority sits on the Regulation Committee and has stated – like his predecessor – that in the event of a dispute between OSR and the ONS, he and the Board would, by instinct, side with the regulator.
Professor Lievesley examined the operation of OSR and the Regulation Committee and concluded that: “Having reviewed the organisation thoroughly, this Review is satisfied that there is sufficient operational independence between ONS and OSR. The Review could find no tangible evidence to support assertions that the two organisations are too cosy or that a fundamental, unmanageable conflict of interest exists between the two that undermines the integrity or quality of the statistics produced by ONS, though it is important to pay attention to the perception of independent scrutiny.”
In line with the Statistics and Registration Service Act (2007) the principal roles of the OSR are to:
Our purpose is to ensure statistics serve the public good by regulating against the principles of Trustworthiness, Quality, and Value. As a regulator, we work through three delivery channels:
Our 5-year plan sets out our vision and priorities for 2020-2025 and how we will contribute to fostering the Authority’s ambitions for the statistics system. Our annual business plan shares our focus for the current year.
Our regulatory approach
Regulatory tools
As the regulator for official statistics across the UK, we have a number of different tools that we use in order to identify issues with official statistics and make recommendations or requirements for improvements:
Engagement with statistical producers
OSR is structured around 8 topic domains, each of which are responsible for maintaining an overview of the statistics produced by relevant government departments and public bodies within that topic. This knowledge ensures that OSR remains up to date on existing and emerging issues and ensure that our reviews and judgements are informed by a deep understanding of the topic.
The domains build strong regulatory relationships with the relevant statistics producers, which support better outcomes for the statistical system, through early and frank exchange of information and intelligence, and securing buy-in from the producers of statistics for the requirements and recommendations set by OSR.
One of these key relationships is with the civil service Heads of Profession for Statistics who sit within each statistical producer organisation. Heads of Profession for Statistics play a vital role in upholding the quality and standards of official statistics as set out in the Code. OSR works closely with the Heads of Profession across government to provide a mix of challenge, advice and support where appropriate.
Whilst we provide specific recommendations to producers as part of our reviews, in general we take a more holistic approach to regulation, providing support, advice and training in additional to our formal regulatory work. This approach ensures that our work with producers secures real change and improvement in statistics, rather than being a performative tick-box exercise. We set the expectation that producers are open and honest about the statistics with us as the regulator and in the public domain. We stand firm on our regulatory decisions but always ensure that we are fully informed by conversations with the producer so that they are proportionate and rooted in the facts.
We pride ourselves on this collaborative approach and consider that it leads to considerably better outcomes for the statistical system. This approach was endorsed by Professor Lievesley, whose review noted that many statistics producers commend the support and guidance from the OSR and that this constructive approach is having a positive impact on compliance with the Code.
Separation from the ONS
For regulation to be effective, it is important that external stakeholders have confidence in the arrangements ensuring OSR’s separation from the ONS. This separation is crucial because it is what enables OSR to make sound regulatory decisions about the ONS’s production of official statistics. These regulatory decisions should be made in the same way, using the same criteria and governance, as for any producer of official statistics.
In October 2024 we published a statement which transparently set out how the separation of OSR from the ONS is achieved in practice. The OSR has separate governance structures, strategy and business planning, reporting lines to the Chair of the Authority, and external communications. As noted above, Professor Lievesley examined the operation of the OSR and the Regulation Committee and found them to be robustly independent.
Regulatory work
Economic statistics
High quality economic statistics are a crucial underpinning for informed decision-making and the functioning of the UK economy. Over the last few years, there have been a number of economic shocks which have brought increased interest in, and scrutiny of, economic statistics produced by the ONS. Over the last year in particular, there has been growing external criticism of ONS.
OSR has proactively undertaken an extensive programme of regulatory work on economic statistics over the last 5 years. These reviews have been fundamental in synthesising stakeholder concerns, identifying issues with the quality of the core building blocks of economic statistics. We have set out clear requirements for improvements from the ONS, and hold the ONS to account by monitoring progress against its delivery of these improvements.
This section sets out regulatory work on the ONS’s economic statistics. It:
Sets out how our April 2025 review builds on the issues identified in our assessments over the preceding 5 years and highlights the urgent need for the ONS to address quality concerns.
Spotlight on Quality Assessments
The UK’s departure from the EU ended the role of the European statistical office (Eurostat) in verifying the quality of UK statistics. In response, we enhanced our work programme of reviews of economic statistics including the development of a Spotlight on Quality assessment framework which will provide continued assurance on the quality internationally comparable economic statistics.
This framework builds on our earlier regulatory reviews on the Living Costs and Food Survey (LCFS) and UK Business Demography Statistics. The framework sets out four key areas to evaluate the quality of statistics: whether the statistics are produced using suitable data sources whether appropriate methods are used transparent quality assurance whether the statistics are sufficiently prioritised and resourced proportionately to their use. This framework has been vital to highlighting issues and areas for improvement in the economic statistics produced primarily by the ONS. It has been used to underpin the requirements we have set for the ONS.
The Spotlight on Quality Assessment programme provides a detailed review of many of the data sources and components that feed into the production of GDP and the broader National Accounts. We have undertaken the following reviews:
ONS’s Price Statistics
The CPIH (Consumer Prices Index including Owner Occupiers’ Housing Costs) is the ONS’s lead and most comprehensive measure of consumer price inflation. It includes the costs associated with owning, maintaining, and living in one’s own home, which is the most significant expense for many households. As such, it is key that the owner occupiers’ housing costs (OOH) element is captured accurately.
As highlighted in our Systemic Review on Housing and Planning Statistics in 2017, the previous method for producing private rental sector statistics had known limitations including being unable to provide estimates of private rent levels and change that were both comparable over time and available at low levels of geography.
To address these limitations, the ONS developed the Price Index of Private Rents (PIPR) which has now replaced the ONS’s Index of Private Housing Rental Prices (IPHRP) and Private Rental Market Statistics (PRMS) and is used for estimating the owner occupiers’ housing costs (OOH) element of CPIH.
PIPR was published for the first time in March 2024, following which, the ONS requested that we assess the statistics against the Code with a view to them becoming accredited official statistics. This process was undertaken in order to provide assurance to users and stakeholders on the quality and reliability of the estimates. We undertook our review at pace, publishing in October 2024.
The OSR review judged that “ONS’s new PIPR statistics generally appear to be meeting users’ needs more effectively than the previous private rents measures that these statistics have replaced.” However, we also concluded that “although the ONS has published supporting methods and quality documentation for PIPR, this does not currently amount to a sufficiently accessible and detailed account of PIPR methods to enable an adequate understanding of the approaches used, the ONS’s rationale for choosing them, and their relative strengths and limitations, for both technical and non-technical users.”
Ultimately, our review determined that the ONS will need to develop and publish the necessary materials; publish NI and full UK PIPR-based estimates; and facilitate an effective evaluation of the UK PIPR series with users before we will consider initiating a full assessment of whether these statistics merit accredited official statistics status.
The review set out five requirements that the ONS will need to address as it further develops the PIPR statistics and required that the ONS publish an action plan by January 2025 setting out how it will address these requirements, and report back to us publicly every three months on its progress. This process ensures that there is transparency for stakeholders and users and that the ONS is held to account.
In February 2025 we set out a forward work plan on assuring confidence in consumer and household price statistics, we have since initiated a review that will focus specifically on the ONS’s approach to transforming its consumer price statistics in advance of a full re-assessment of CPI and CPIH statistics. We will also begin a review of Household Cost Indices (HCIs) later this year.
Labour market statistics
We have focused our work around the challenges that the ONS has faced with its labour market statistics on three distinct themes:
Responding to a changing labour market
Employment and jobs statistics are essential for understanding the patterns and dynamics of the UK labour market. They are used widely by a variety of stakeholders, for example within UK Government and by the Bank of England to develop and monitor government policies and so it is important that they are accurate, high quality and clear to fully serve the public good.
Over the last few years, labour market statistics have faced a variety of challenges related predominantly to falling response rates. OSR has provided regulatory oversight of these issues and the ONS’s response, undertaking a significant volume of regulatory work on labour market statistics in the past few years as set out below.
In response to growing concerns about the reliability of the Labour Force Survey in 2020, we assessed the UK employment and job statistics produced by the ONS.
The report emphasised the importance of the ONS adopting a flexible approach. It highlighted the labour market and economy are in constant change, and that the statistics that describe the labour market must therefore adapt to reflect those changes. This includes embracing new data sources and navigating the impact of COVID-19. We concluded that “ONS needs to demonstrate drive and ambition to fill the data gaps and match the pace of change in the labour market, engaging effectively with users to ensure their needs are met.”
In our report we identified areas of good practice such as the labour market statistics team’s collaboration and engagement with a wide range of users and stakeholders. We also set out 12 requirements for the ONS, which were necessary in order to ensure that these statistics could continue to be designated as accredited official statistics (then referred to as National Statistics).
Response rate challenges
We have seen a long-term trend of response rate challenges facing the LFS, which became acute when the sample boost in place to enable pandemic operations was removed in July 2023. Following this, in October 2023, the ONS suspended publication of its estimates of UK employment, unemployment and economic inactivity based on LFS data and announced that it would publish a new experimental series using additional data sources in its place. This short notice change to methods of a key series had a significant impact on user confidence.
In response, we immediately announced and initiated a rapid review of these experimental statistics which was published in November 2023. This review set out key requirements for the ONS on:
As a reflection of the significant concerns about quality, the review resulted in the removal of the accredited official statistics status from LFS-based estimates. Following enhanced quality information provided by producers at our request, we also removed the accreditation from other outputs based on data from the Annual Population Survey which is based on responses to wave 1 and wave 5 of the LFS plus a boost sample.
In response to the ONS reintroducing the LFS-based labour market statistics in February 2024, we carried out a short review. A key theme that emerged from this review was the need for improved, clear and open communication from the ONS. The review set out requirements around: communication of plans and priorities; accessibility of updates and communications; explaining how the data should be used; communication of data quality issues and improvements; and transition to the TLFS. In August 2024, we carried out a follow-up review to check the progress made against the requirements.
ONS’s Transformation plans for the Labour Force Survey
We have also carried out regulatory work throughout the development of the Transformed Labour Force Survey (TLFS). Throughout this period, the ONS was developing in parallel the TLFS, which was intended to address many of the concerns and shortcomings of the LFS, but this work has also faced significant delivery challenges.
We carried out our TLFS review in three phases with the aim of sharing early regulatory insights to help the ONS in ensuring the new survey meets the standards of the Code. The first phase (which started in April 2022) focused on the design and development work the ONS had planned before transitioning to the new survey approach.
We published our initial findings on the TLFS in November 2022 which set out a range of requirements, including on enhancing public confidence and maximising the public value of the TLFS; communicating impacts; and supporting public confidence in the transformation process. In July 2023, we published an updated letter and progress report following phase two of our review.
In February 2025, we reported the outcome of phase three of our review of the ONS’s LFS transformation. This report consolidated OSR’s work on both the LFS and TLFS, bringing together our judgements to date and providing updates on the remaining open recommendations and requirements.
Following recommendations set out by OSR, the ONS has widened its user engagement with the introduction of the stakeholder panel and expert data sharing groups and has been publishing updates on the labour market transformation – progress and plans. In December 2024, the ONS also published an interim action plan based on the results of its ‘lessons learnt’ exercise conducted in summer 2024; published the detail of an independent methodological review; and explained its plans in an accessible way. The ONS has revised its plans for the TLFS and in response we made further recommendations for the ONS to set out detailed plans for transitioning to the TLFS, and to set out plans for regular reporting on the progress of the interim action plan from its ‘lessons learnt’ exercise. We have asked the ONS to report on progress again by July 2025.
We continue to closely monitor the ONS’s work to improve the LFS. We will maintained our engagement with the ONS and users to understand whether these changes have increased quality sufficiently to meet user needs. We have asked the ONS to report on progress again by July 2025.
Review of ONS economic statistics
In April 2025, we published our report based on our Systemic Review of ONS Economic Statistics. The report provided a synthesis of the concerns surrounding the ONS economic statistics that had emerged from our work over the last five years, and feedback from stakeholders.
The report was direct in recognising the need for urgency in addressing the declining stakeholder confidence in ONS’s economic statistics, concluding that:
The review also set requirements that the ONS must address:
Population statistics
The UK’s population statistics are going through a period of profound challenge and change.
This section sets out how OSR’s work on population statistics has highlighted the effective work undertaken by the ONS, National Records Scotland (NRS), and Northern Ireland and Statistics and Research Agency (NISRA) on the 2021 and 2022 Censuses respectively, but also brings out the issues surrounding measuring gender identity, and the opportunities and challenges from the use of administrative data.
Censuses in the UK
We have conducted assessments of the censuses produced by the ONS, NRS and NISRA. Our assessments have been conducted in three phases. In October 2019, we published our reports on Phase 1, focusing on the planning and consultation activities undertaken by the census offices across the UK. In November 2021, we published our Phase 2 Assessment reports, focusing on the strategies for developing and providing outputs for both the England & Wales Census 2021 and the Northern Ireland Census 2021. For Scotland Census 2022, our Phase 2 Assessment report was published in April 2023.
The phased approach is essential for the Census outputs as we have historically granted accredited official statistics status at the end of phase 2 which is prior to the publication of the outputs themselves. This is due to the national significance of these statistics and the importance of reassuring users as to the quality of them at the time of publication, rather than retrospectively. This approach means that it is essential for the departments to meet the requirements set out in phase 1 and phase 2 before accredited official statistics status is granted.
For Scotland’s Census 2022, NRS faced unexpected challenges given that the overall response rate was lower than had been anticipated (89.8% compared to target of 94%). The media and users were concerned that statistics derived from the Census would not be fit for purpose because of the response rate. As a result, NRS undertook a number of steps in collaboration with international census experts to change how the final census estimates were calculated, involving the use of administrative data alongside the Census Coverage Survey and census responses in the estimation process. Using OSR principles of intelligent transparency and OSR communicating uncertainty guidance, NRS carefully considered its communication approach for its first outputs of the Census 2022 data. We commended NRS’s dedication to meet the needs of users and follow the standards of the Code of Practice, including most recently by advocating this good practice in a published communicating uncertainty case study.
We published our phase 3 assessment report of the 2021 Census in Northern Ireland in February 2025. This final report confirmed that the 2021 Census statistics in Northern Ireland are produced in compliance with the Code. Our phase 3 assessment of the 2021 Census in England and Wales is ongoing with a projected summer 2025 publication date. Our phase 3 assessment of the Scotland Census will be undertaken in 2025/26.
Review of Gender Identity in the ONS 2021 England and Wales Census
Information on individual’s gender identity was collected on a voluntary basis for the first time in the ONS 2021 England and Wales Census. As such, the data provided the first ever nationally available estimates for England and Wales on the size and characteristics of the trans population. In addition, the question developed for the Census represents the current Government Statistical Service (GSS) harmonised standard in development for collecting data on gender identity.
Following the first release of census statistics on gender identity in England and Wales in January 2023, concerns were raised about the published estimates of the trans population. As additional census data were published, these concerns extended to the relationship between gender identity and proficiency in English. OSR also received concerns about the level of methodological information published.
OSR undertook a review of these statistics and published an interim report in October 2023 and a final report in September 2024. Learning from new evidence in Scotland’s Census, the ONS wrote to us on 5 September 2024 to request that the gender identity estimates from Census 2021 in England and Wales should no longer be accredited official statistics, and should instead be classified as official statistics in development. The ONS’s proposal was consistent with our report findings, and we accordingly removed the accreditation for these statistics. We also concluded that the issues were unique to the statistics on gender identity, and therefore all other outputs from the Census 2021 in England and Wales are unaffected and remained as accredited official statistics. Our work also found that the ONS had been somewhat closed and at times defensive, in responding to concerns raised by users.
Our final report shared our recommendations on the steps the ONS must take to help users of the census gender identity statistics understand their strengths and limitations and set out the development work we consider is required on the GSS gender identity harmonised standard.
The ONS wrote to us in December 2024 updating on their progress towards meeting the recommendations. This included publishing a workplan for developing harmonised standards for sex and gender identity data collection and new Gender Identity Data Harmonisation interim guidance for statistics producers.
Following these publications, we updated our existing guidance on collecting and reporting data about sex and gender identity in official statistics in December 2024 to include these new publications.
On 26 March 2025, the ONS published a blog further updating on the actions it is taking to meet our recommendations. These actions included publishing additional guidance on the appropriate use of the gender identity estimates from Census 2021 in England and Wales and information on the uncertainty associated with them. We consider this to be an excellent research report which includes example use cases at different levels of geography and population and addresses anomalies and implausibility’s. We are confident this practical information will users to better understand the uncertainty in the data and its implications for use.
The ONS is also making progress with developing harmonised standards for sex and gender identity data collection. We have asked that the ONS continues to keep OSR updated as it develops these harmonised standards.
Admin-based population estimates for England and Wales
Admin-based population estimates (ABPE’s) have huge potential to provide more timely, detailed and potentially more accurate population data compared to traditional census-based methods. The ONS intends for the ABPE’s to become the official population estimates for England and Wales in 2025. Given the extensive use of population statistics, it is vital that this new methodology has appropriate oversight and scrutiny.
Our phased assessment approach for ONS’s Admin-based population estimates (ABPE’s) for England and Wales statistics aims to provide reassurance to users on the new methods by the ONS for producing population estimates in England and Wales.
We published our phase one assessment of these statistics in July 2024 which focused on reviewing quality. As part of this assessment, we commissioned an independent review from Professor Arkadiusz Wisniowski, University of Manchester to inform our judgements around the suitability and quality assurance of the data and methods. Our assessment identified 11 requirements for the ONS to act on that will help to enhance the public value, quality and trustworthiness of these statistics. These requirements covered areas such as governance, data quality, methods, revisions, user engagement, and communication. The requirements included:
Since our report was published, the ONS has used our findings to help shape and steer its development work for the ABPE’s. In October 2024 the ONS published an action plan for how it will develop population statistics. This sets out that the work to address and build on the requirements and recommendations from the assessment will be iterative. Over the last six months, and in response to our findings, the ONS has developed and published a population and international migration statistics revisions policy, introduced quarterly updates to keep users up to date with its plans including its work on ABPEs and increased its user engagement activities in a co-ordinated and transparent way. We continue to engage with the ONS as part of our follow-up phase to scrutinise the ONS’s activities and will consider the next phase of our assessment in summer 2025.
Other regulatory work
Domain summaries
OSR is structured into eight topic teams, called ‘domains’. The two preceding sections have summarised some of the key work undertaken by our Economy, Business and Trade domain and our Population and Society domain respectively.
This section provides a short overview of our remaining six domains as well as recent regulatory work.
Children, Education and Skills: This domain oversees the regulation of data and statistics concerning all stages of education from early years to university and beyond, including statistics on teachers and lecturers, learners, and looked after children. We recently carried out an assessment of the Higher Education (HE) Graduate Outcomes Data and Statistics produced by the Jisc under the Higher Education Statistics Agency (HESA) brand. We published our report in April 2024 and confirmed the accreditation of the statistics without requirements for improvement. We are providing support to the newly created Welsh Government Sponsored Body, Medr, which is responsible for a number of official statistics previously published by Welsh Government in an addition to outputs from the Higher Education Funding Council Wales (HEFCW). In previous years we have also carried out assessments on the Achievement of Curriculum for Excellence Levels statistics produced by Scottish Government, and the Key Stage 4 performance statistics for England produced by the Department for Education.
Crime and Security: This domain covers statistics on crime, policing, justice systems (family, civil and criminal) and national security. This domain has undertaken a number of significant and impactful reviews over the last few years including: the Fraud and Computer misuse statistics for England and Wales published by the ONS; the quality of Criminal Court Statistics for England and Wales produced by the Ministry of Justice and based on data from the HM Courts Tribunals Service (HMCTS); and Police recorded crime statistics published quarterly by the ONS, based on Home Office data collected from the 43 individual police forces in England and Wales and British Transport Police. We have also carried out assessments on the Scottish Prison Population statistics produced by the Scottish Government and Police Officer Uplift statistics produced by the Home Office.
Health and Social Care: This domain oversees the regulation of statistics concerning the health of the UK population and health and social care services provided in England, Wales, Scotland and Northern Ireland. Our Health and Social Care domain played a vital role during, and following, the COVID-19 pandemic in rapidly reviewing the quality of statistics being used by Government and the public including:
In addition to work on statistics relating to COVID-19, the domain has also assessed Accident and Emergency (A&E) Activity Statistics in Scotland and statistics about the workforce employed by adult social services departments in England.
Housing, Planning and Local Services: This domain oversees statistics on a range of topics, including: house building; household estimates and projections; homelessness and rough sleeping; housing need and demand; land stock, use and development; and local authority planning. It also covers information on local services such as fire and rescue services. This domain has undertaken a wide range of compliance checks in the last few years including on Statistics on Council Tax in Wales, Social Housing Lettings in England produced by the Ministry of Housing, Communities and Local Government, and Valuation Office Agency Council Tax statistics. The domain has also assessed statistics on Statutory Homelessness in England produced by the, then named, Department for Levelling Up, Housing and Communities (DLUHC).
Labour Market and Welfare: The Labour Market and Welfare theme includes statistics measuring different aspects of work and jobs and covers people’s employment, working patterns and the types of work they do. The theme also covers any earnings and benefits they receive. Currently, this domain is primarily focused on the LFS and TLFS as summarised in the ‘Economic statistics’ section above. However, other examples of work include an assessment on the Personal Independence Payment statistics produced by the Department for Work and Pensions.
Transport, Environment and Climate Change: This domain covers statistics on transport and transport infrastructure; food and farming; the natural environment; energy; fuel poverty; and climate change. This domain maintains strong stakeholder relationship with the wide range of producers who are active in producing statistics in this topical area. We have intervened on subjects that have attracted much public interest such as improving transparency of Welsh Governments’ 20-mph speed limit data. We have previously undertaken regulatory reviews of some key biodiversity indicators including our assessment of Defra’s butterfly statistics as well as more systemic reviews such as accessibility and coherence of UK climate change statistics.
Transparency on the use of data
One of our flagship campaigns relates to the way statistics and data are used in communication. The campaign is based on our principles of intelligent transparency. The core of intelligent transparency is the requirement that all statements made by those in government involving statistics or data must be based on publicly available data, preferably the latest available official statistics where possible.
There have been several high-profile endorsements of intelligent transparency including the report from the PACAC on Transforming the UK’s Evidence Base in May 2024, which commended our work on intelligent transparency and noted that “This Intelligent Transparency guidance has driven the publication of several datasets which would otherwise remain hidden to members of the public, and has been welcomed by many organisations who rely on good data”. The Royal Statistical Society (RSS) also supports the campaign and has integrated the principles of intelligent transparency into the RSS’s new Principles to support statisticians making trade-offs in pressurised situations.
Casework
Through our casework process we regularly receive complaints about the use of data and statistics, often relating to our principles of intelligent transparency. This process is vital in OSR upholding the standards of the use of official statistics and beyond in public debate, holding individuals and organisations to account when needed. In the international landscape of official statistics, this function is relatively unusual, but we consider it an important part of underpinning confidence in statistics and data. This section provides some examples of our recent key interventions.
In October 2024, we were made aware of an unsupported statement made by the Prime Minister, Sir Keir Starmer at the Labour Party Conference regarding immigration returns. At the time the Prime Minister made the claim there was no Home Office data or statistics available in the public domain for the relevant time period to support this statement. We worked with the Home Office and this led to the publication of an ad-hoc statistical release, which provided the underlying data that related to the statement.
In March 2025 we wrote to Peter Schofield, Permanent Secretary for the Department for Work and Pensions (DWP) regarding a statement on the number of people on Universal Credit health with no requirement to look for work in a press release. We judged that the statement that the number of people claiming disability elements of Universal Credit had “increased by 383%” presented an ‘entirely misleading’ picture to the public as it did not recognise that the majority of this increase is due to the process of migrating people from legacy benefits over the last few years. When these people are accounted for, the actual increase in the number of people claiming disability elements of Universal Credit is around 50%. We requested that the press release was updated that week to remove the reference to the 383% figure and that it was not to be used going forward. DWP actioned the change to the press release shortly after and the Permanent Secretary responded to us committing to involving lead statisticians and analysts at all stages of the process, and that there will be appropriate oversight from their Head of Profession for Statistics.
In October 2022, we wrote to Scottish Government in relation to concerns that had been raised with us about the NHS inform dashboard. The NHS Inform dashboard showed the numbers of patients treated in the last quarter and their median wait times by clinical specialty. However, patients who have not yet been treated, some of whom may have been waiting a long time, were not included in these statistics. As such, we judged that the dashboard could potentially mislead some patients about the length of time they may have to wait. Based on our recommendations, Scottish Government implemented improvements to the way that figures were presented in late 2022. In October 2024, Public Health Scotland wrote to us outlining their plans to overhaul the dashboard which will result in a range of improvements in the presentation of the statistics which will provide a better reflection of people’s actual experience of waiting for appointments and treatment.
During the lead up to the 2024 General Election, we published a statement on claims made by the Conservative Government about the UK’s plan to “increase defence spending to 2.5% of GDP by 2030 – an increase of £75 billion”. We determined that the figure of £75 billion did not provide a clear picture to the public as it assumed that annual spending on defence would remain flat in cash terms. If the calculation assumed that defence spending was held at the share of GDP originally planned for 2024-25 then the proposed cash ‘increase’ would drop from £75 billion to £25 billion. Our statement notes: “Cumulating spending increases (or cuts) over several years to derive a large cash figure for presentational purposes does not in general facilitate public understanding of the data in question – the longer the period you choose, the bigger the number you get.”
An evolving statistical system
We consider that the UK data and statistics environment is constantly evolving which presents new challenges and opportunities for official statisticians and analysts. We consider many of these aspects through our reviews and through much of our wider work.
The State of the Statistical System
The State of the Statistical System is an annual report produced by OSR which presents our view on the performance and challenges facing the UK’s statistical system.
The 2023/24 report, published in July 2024, emphasised the increasing strain on the system due to financial and resource pressures, and the need to prioritise core statistics to ensure they are adequately resourced and funded.
To address the issues in the report we set out a number of recommendations. These included that the GSS develop a strategic plan for household data and invest more in its approach to engagement, and that the statistics system shares knowledge and best practice on delivering transformation programmes.
Data sharing and linkage
In 2023 we published a review of data sharing and linkage across government with 16 recommendations for the statistical system as well as a follow up report in July 2024 which assessed the progress that had been made.
Our 2023 report had positive impacts on several projects relating to data sharing and linkage. These impacts include influencing the strategic approach taken by the Department for Science, Innovation and Technology (DSIT) to reviewing cross-government data sharing policy; developments in the Data Marketplace led by the Central Digital and Data Office (now Government Digital Service); the implementation of Wave 2 of the Public Engagement in Data Research Initiative (PEDRI); and technical innovation by the ONS Data Science Campus in developing new privacy-enhancing technologies (PETs).
However, our 2024 follow-on report concluded that despite welcome pockets of innovation, there continues to be a failure to deliver on data sharing and linkage across government, with many persisting barriers to progress. Linking datasets for research, statistics and evaluation – both across government and among external researchers – is not yet the norm in the UK statistical system. To make this a reality, stronger commitments to prioritise data sharing and linkage are required. Such commitments further need to be endorsed and sustainably resourced by senior political and Civil Service leadership.
Our report also acknowledged specific process barriers to data access and linkage. Among these, we noted that concerns that data use cases are often too tightly defined to enable the use of data in policy development are particularly relevant to the success of the Integrated Data Service (IDS). OSR are working with members of the IDS team and the UKSA Research Accreditation Panel to consider programmatic access.
Conclusion
This submission summarises the effective work of OSR, and the tools we use to uphold compliance with the Code of Practice for Statistics. It shows how our work ensures accountability for the production of official statistics that comply with the principles of Trustworthiness, Quality and Value. This submission also provides clear examples of where our work has identified issues, set requirements, and secured change across a wide suite of statistical outputs and data practices, often against a backdrop of significant issues or concerns.
Ed Humpherson
Office for Statistics Regulation
How well served are policy-makers, researchers, businesses and citizens, by the data that ONS produces and the services it provides?
Summary
The Office for National Statistics (ONS) is the UK’s national statistical institute and largest producer of accredited official statistics. It produces statistics, data and analysis to support a wide range of users including decision makers, researchers, businesses, and citizens. The ONS continually engages with its users to understand and meet their evolving needs and ensure that its outputs and services are of a high quality, accessible and relevant.
As the Committee is aware, the National Statistician, Professor Sir Ian Diamond, resigned earlier this month due to health issues. Emma Rourke, Deputy National Statistician for Health, Population and Methods, will be Acting National Statistician pending longer term arrangements being put in place.
The ONS continues to face challenges including falling survey response rates and operating within a tight financial and human resources environment. We remain committed to continuous improvement of our methods and approaches. Alongside this, there is an ongoing independent review of the performance and culture of the ONS being led by Sir Robert Devereux, former Permanent Secretary at the Department for Work and Pensions and the soon to be completed Spending Review. In this context the ONS continues to review its priorities and will make changes to its work as required, to further strengthen our approach to continuous improvement and enable the organisation to deliver our core mission of providing statistics for the public good.
The Office for National Statistics
The ONS is the executive office of the UK Statistics Authority (the Authority). It delivers independent, high quality and relevant statistics and analysis. The wide range of economic and social statistics we produce includes the UK’s National Accounts (such as gross domestic product (GDP)), vital events statistics (such as births, marriages and deaths) and labour market statistics (such as employment, unemployment and earnings) amongst others. The ONS also designs and runs the census in England and Wales every 10 years.
Our statistics and analysis are crucial evidence for decision making and monitoring by central and local government, the health service, businesses, charities and communities across the UK. It also informs public debate.
The ONS responds to changing contexts and user demand for more flexible, tailored and granular data. We are transforming our approach to how we produce statistics across the economy, population and society. This includes advancing data linking across government to enable faster, evidence-based decisions, and gripping the opportunities and challenges of new technologies (such as artificial intelligence (AI), including large language models) to shape and support thriving analytical and statistical systems for the future.
Our priorities are driven by our statutory objective set out in the Statistics and Registration Service Act, the UK Statistics Authority strategy for the statistical system ‘Statistics for the Public Good’, and the relevance and impact of our work to users and the public, with a focus on where we are uniquely placed to deliver.
ONS Strategic Business Plan 2025-2026
We have been open about the challenges the ONS has faced in recent months and set out a renewed focus on our core statistics in the ONS Strategic Business Plan for April 2025-March 2026, published in April 2025. This highlights that delivering our suite of economic and population statistics remains our core function and is reflective of decisions we have made to prioritise resources. GDP, prices, labour market and population statistics take prominence in our outputs.
We remain focused on producing the highest quality statistics and are committed to continuous improvement of our methods and approaches. Alongside our core outputs, we are undertaking vital transformation work, including delivery of our labour market statistics and improving the quality, granularity and timeliness of our prices data. Acknowledging the complexities of the challenges and the vital importance of our statistics to users, we have strengthened our engagement with stakeholders and channels for external challenge, support and expertise to inform our approach.
Our four key strategic priorities which will guide day-to-day activity of the organisation are:
Given the tight financial and human resources backdrop and the need to prioritise our most critical statistics, difficult decisions, including to stop or reduce work, will need to be made in the coming period. While the prioritisation necessary to remain affordable will not satisfy demand from some users, we will continue to deliver impact by protecting our core deliverables.
Understanding user needs
The services that we provide can only happen when we listen to and work in partnership with our users. We engage with a wide range of users and stakeholders to increase both their understanding of our work as well as our understanding of their evolving needs. We are committed to ensuring our statistics are accessible, inclusive and trustworthy, representing and serving everyone in society.
We engage with users through a range of methods including regular meetings, consultations, stakeholder surveys, events, tailored explainer webinars for specific audiences, focus groups, expert advisory panels and user research.
As well as engaging our users on our statistics and analysis, we regularly seek feedback on their levels of satisfaction. Our most recent feedback showed high levels of use of our core statistics on population and the economy along with agreement that we fulfil our mission to produce “High quality data and analysis to inform the UK, improve lives and build the future”, are trustworthy and that our statistics are relevant and of a high standard.
In listening to users, we are also able to better understand how the challenges we are facing are impacting them. For example, how the impact of falling survey response rates on outputs, specifically labour market statistics, is impacting economic decision making. Users have also highlighted delays to some publications, the need for improvements to our website and a desire for more granular data across multiple topic areas. We fully recognise these points and have plans to address them.
In her Review of the Authority, Professor Denise Lievesley recommended that ‘It is time for the Board to move into a more visible, ambitious space, primarily through establishing a Triennial Statistical Assembly which will consult widely with statistics users and producers to understand the range of views regarding the priorities and data needs for the UK’. In response to this recommendation, we held the inaugural UK Statistics Assembly in January 2025. It was attended by over 550 attendees from a wide variety of sectors and roles.
The Assembly was summarised in an independent report produced by Professor David Hand, the then Chair of the National Statistician’s Expert User Advisory Committee (NSEUAC), and highlighted four high-level priorities for the Authority and Government Statistical Service:
We plan to build on the success of the Assembly through a refreshed user engagement strategy, taking these priorities into consideration as we do so. The Authority Chair, Sir Robert Chote, will also deliver a lecture in July setting out the progress of the statistical system and priorities, drawing on the insights of the Assembly and the Office for Statistics Regulation’s (OSR) annual State of the Statistical System report.
Meeting user needs
Through our programmes, transformation work and statistics, the ONS is working hard to deliver statistics and analysis that meet user needs. This has involved significant prioritisation. The following paragraphs provide examples of work we do to understand and meet users’ needs and to inform policy makers, researchers, businesses and citizens.
Dissemination of Statistics
The ONS’s outputs, in line with the rest of the Government Statistical Service (GSS), are regulated by OSR. Equality of access to official statistics is a fundamental principle of statistical good practice. We publish our statistical releases on the ONS website and users are also able to request extra information from the ONS and see the information others have requested.
We are committed to improving the user experience on the ONS website and over the past year have been addressing website performance and stability as well as wider improvements to address feedback from users. We have launched new website page previews, most recently on prices statistics, with new navigation, page designs and smarter content for users to provide feedback on.
Priority issues for decision makers
The ONS works closely with partners to provide responsive analysis that directly address policy priorities, including the missions introduced by the Government. These statistics, and many others across the organisation, provide vital insights for policy formulation across government.
The National Statistician also leads the GSS and Analysis Function. The ONS sits at the heart of the GSS and Analysis Function and works with the network of UK Civil Servants to provide the statistical evidence base, professional advice and analysis required by decision-makers to ensure policy and operations are evidenced and deliver value for money.
This collaborative approach to delivering statistical outputs, responding to analytical demand and the continuous improvement of our statistics across the statistical system will continue to be an underpinning element to our plans in 2025/26.
The ONS’s Analytical Hub has a close partnership with the Joint Data and Analysis Centre (JDAC) in the Cabinet Office where we directly provide data and strategic analysis to support policy and decision making at the heart of government.
Delivering rapid insights in changing circumstances
We publish a range of statistics to provide timely indicators for users covering the effect of developing world events on the UK economy and society.
For example, the Opinions and Lifestyle Survey (OPN) collects information monthly on a variety of topics relating to people’s experience of daily life and events, including questions about what people feel are important issues, their health and well-being. The content on the survey changes regularly, to keep pace with changing content requirements from users.
The value of these ONS surveys such as the OPN or the Business Insights and Conditions Survey (BICS) were prominently demonstrated during the Covid-19 pandemic. They were regularly updated and adapted to reflect changes in policy and our understanding of the virus. The ONS consulted with a wide range of other government departments on a regular basis as it developed questions.
Real-time indicators are also invaluable for enhancing and developing core statistics by providing timely insights that complement traditional data sources. For example, during the Covid-19 pandemic, the ONS used real-time data from sources like card spending and mobility indicators to quickly gauge economic activity and societal changes.
Providing safe research environments for accredited and approved researchers
We make de-identified record-level data available to accredited or approved researchers through the Secure Research Service (SRS) and the Integrated Data Service (IDS) services to facilitate work on research projects for the public good. The SRS makes static snapshots of data available to researchers using a windows desktop environment and the IDS makes flexible views of indexed data available using the tools and scaling available through the google cloud. The SRS is one of the largest trusted research environments in the UK, around 6,000 accredited researchers having potential access. Of these, around 1,500 are actively working on research projects at any given time.
Building on the success of the SRS, we are now migrating users with the highest value use cases to the IDS, enabling far greater flexibility and broader ranging analysis work programmes.
This will also enable far greater insight into our core national statistics relating for example relating to trade, employment and growth, and the interactions between them at national, regional and local levels.
Delivering Local and Sub-national Insights
ONS Local is a dedicated analytical advisory service for Local Government and local decision makers with team based in each of the English regions, and in Wales, Scotland and Northern Ireland. A core part of the team’s role is engaging with local users to understand data and information needs and gaps, in addition to producing bespoke analysis for their local stakeholders. ONS Local and our subnational statistics, together provide unique local information to support national, regional and local leaders’ understanding of topics through a place lens.
To this end, the ONS has developed a tool called Explore Local Statistics, that allows users to find, visualise, compare, and download local data in one place. This service brings together a wealth of data across various topics, including the economy, education, health, and wellbeing, making it easier for local leaders and decision-makers to access the information they need. Users can search for data by postcode, local authority, region, or parliamentary constituency, providing detailed insights into specific areas. The service also allows for comparisons between different areas or clusters with similar demographic or economic characteristics, enhancing the ability to make evidence-based decisions.
How is the UK’s data environment evolving, and what challenges and opportunities does this present official statisticians and analysts?
The UK’s data environment is evolving at pace. There are more data, insights, and opportunities, and the ONS is acting to realise the full value of data while maintaining high levels of trust and transparency.
Challenges remain in streamlining and simplifying approval processes to these new sources and developing the skills and capability to make best use of them, whilst continuing to address the challenges of collecting information from traditional survey sources.
Survey data collection challenges
Changes in society and the pace of technology are having a direct impact on how people perceive their data and interact with surveys and government services.
ONS surveys, both social and business, are the primary data source for statistical producers in the UK, central to the nation’s most significant economic and social indicators, and despite the increasing use of administrative data, they remain vital.
The sharp fall in household survey response rates both in the UK and internationally is well-known, often linked to an increased difficulty in accessing properties, increased cautiousness to share information, and declining trust in government and public institutions. This can affect data quality and has been evidenced most prominently by the impacts of survey response rates on the Labour Force Survey (LFS). The ONS’s plans for a long-term solution to the challenges faced by the LFS remains the online first Transformed Labour Force Survey (TLFS), more details about which can be found on the ONS website.
Although integration of administrative data sources is already taking place to produce economic outputs and remains our preferred data source, we recognise that surveys currently still play a vital role in collecting data from businesses. Direct data collection tools also become more important as AI is increasingly used due to the need for new, high-quality data.
Linked to this, but a separate challenge, are our legacy statistical production systems. As highlighted in our business plan, addressing our IT and coding legacy systems remains a key focus for 2025/26.
A legal requirement to complete ONS business surveys, coupled with predominately online collection, has seen business survey response rates improve to pre-pandemic levels.
What the ONS is doing in relation to survey data collection
The ONS is increasingly integrating a wide variety of data sources to produce high-quality research and statistics and adapting survey methodologies to encourage greater coverage. We have built relationships across the public sector to implement regular flows of anonymised administrative data collected as part of the delivery of frontline services, such as tax, benefits, health and education. We have also built relationships with the private sector and other bodies, enabling secure access to anonymised big data, such as aggregated financial transactions and mobile network operator data, and scanner data from supermarket sales.
The ONS has a vision for a more efficient and effective social survey system delivered through innovative use of administrative and alternative data across the survey end-to-end. We are also exploring and embedding opportunities to use AI and other innovative digital technology across the survey end-to-end. This will significantly improve how we meet changing data user needs with a sustainable, robust, resilient and agile survey delivery system.
To enable urgent quality improvements to the social surveys feeding economic statistics, we received additional funding from HM Treasury in 2024/25. This was invested in increasing our interviewer numbers, implementation of changes to bolster retention, and increasing incentives for survey respondents. This has helped to improve performance on key surveys, but we need to do more to improve performance across our full survey portfolio. Our survey recovery strategy, including focused resources in this area, will help us continue to improve response rates in an increasing challenging environment.
The ONS is already transforming how we collect data to an integrated and modularised suite of surveys through our Business Survey Strategy. This will reduce the burden placed on businesses and improve engagement, improving the quality of the data we collect. We are also expanding the use of AI and moving to cloud-based collection and production systems.
Administrative data
Many opportunities and challenges are linked to the growing scale and types of data that are available, in particular, the proliferation of administrative data within the public sector and the growth in alternative, big data.
The increasing availability and content of administrative data present the opportunity for the ONS to produce more frequent and timely statistics that sustain a better level of quality over time.
The quality of administrative data varies, with issues including data completeness, differences between concepts (including reporting periods), timeliness and frequency of data deliveries, consistency of data deliveries and the availability of metadata. Nonetheless, linking administrative data with survey data provides valuable insights into how they can be used to improve our understanding of survey bias, and to develop new outputs that make the most of the strengths of all sources.
The ONS has been investigating the use of primarily administrative data to produce annual population estimates, and a range of other types of estimates historically enabled only by the census. The ONS has worked with statistical offices in Scotland, Wales and Northern Ireland to consider the viability of taking similar approaches across the UK, with an agreement on this topic signed in November 2022.
This is an area of ongoing research and development, and the Authority is set to announce its recommendation on the future of the census in England and Wales in the summer.
The ONS has already moved to administrative measures of international migration due to unavoidable challenges with its traditional sources for these statistics. The ONS has confidence in the long-term strategy for migration estimates, and their future coherence with admin-based population estimates, and we are working with users to increase confidence as new methods mature.
A key enabler of this work is improving the sustainability of the supply of administrative data to the ONS, and improvements to their content and quality, working in partnership with data suppliers.
As we consider embedding new methods, and question the role a potential future census might play in the ONS’s long-term statistical design for population statistics, there is a need to balance ambitions for research and development alongside the requirement for a steady state of operational delivery in line with user needs, and resource constraints. This is a challenge for the whole of the UK, not just the ONS.
Data sharing across Government
Through extensive engagement across government departments, we are making some progress in acquiring new administrative data sources. However, this continues to be very time consuming, and each data sharing agreement can take months or years to agree.
Data owners are understandably risk adverse, often resulting in complex agreements, with conditions varying significantly between sources. In her Review of the UK Statistics Authority, Professor Denise Lievesley highlighted that ‘systemic and cultural barriers to responsible data sharing between government departments’ hamper the Authority’s efficacy, including the work of the IDS.
We continue to work with other government departments to remove blockers and simplify approval processes, and we hope plans to develop a National Data Library will increase the focus on resolving these challenges.
Data linking
The ONS has developed a suite of core linkage indexes covering business, the population and addresses which enables datasets to be safely de-identified and linked at scale without the need to share personal data with analysts. This linkage enables full exploration of the utility of administrative data for statistics and supports addressing data gaps going forward.
Using this approach, we are aiming to increase standardisation of data production and usage within not only the ONS but across the public sector.
With advances in AI, there is further opportunity to use the new technology to bring efficiencies to data processing and to improve data quality. However, this opportunity cannot be fully realised unless data has foundational quality such as high-quality metadata and clear governance, ethical and security frameworks in place. Good progress is being made in the ONS piloting the use of Generative AI to speed up data processing and improve user experience.
The National Data Library
The ONS continues to support the Government Digital Service (GDS) and Department for Science, Innovation and Technology (DSIT) on initiatives to improve data sharing, including the development of the Data Ownership Model for Government, identification of Essential Shared Data Assets and data discovery through the Data Marketplace.
Plans for a National Data Library (NDL), whilst still in the discovery phase, give a further opportunity to drive alignment across data sharing infrastructure services.
The ONS has shared key lessons relating to data sharing with DSIT as part of the NDL discovery, and we continue to help shape the longer-term solution. There will clearly be a role to signpost to the right service, support users access the right platform for their needs, and address data sharing barriers across the eco-system, particularly to support the government deliver its missions.
Office for National Statistics
Dear Lord Wood,
Thank you for inviting me to give evidence for the Committee’s inquiry on Preparing for an Ageing Society. During that session on 1 April, I promised to follow-up with the Committee on several topics, as our discussion ranged from population projections to fertility rates and migration. I have annexed further information on, specifically:
I hope this is helpful, and please do let me know if you or the Committee have any further questions that the Office for National Statistics (ONS) can help with.
Yours sincerely,
Mary Gregory
Director for Population Statistics, Office for National Statistics
The national population projections give an indication of the potential future population size of the UK and its constituent countries. These statistics are widely used in planning, including fiscal projections, health, education and pensions. National population projections are not forecasts and do not attempt to predict potential changes in international migration. Migration assumptions do not directly account for recent and future policy or economic changes. Demographic assumptions for future fertility, mortality and migration are based on observed demographic trends.
The ONS publish population projections of the future size and age structure of the population of the UK and its constituent countries. The 2022 based National population projections show an old age dependency ratio of 278 people above pension age to every 1,000 people aged 16 to pension age.
State pension age is planned to be raised from 66 to 67 between 2026 and 2028. Based on ONS population projections, to hold the current old age dependency ratio of 278 constant, pension age would need to rise to 68 in the first half of the 2030s, 69 in the second half of the 2030s, and 70 in the 2040s.
The ONS has published methodology on comparing national population projections to mid-year population estimates from 1971 to 2022 with population estimates, births, long-term international migration, and deaths, including measures of error. This helps users understand the uncertainty inherent in population projections, where this has come from in our previous releases and for them to make judgements on the potential uncertainty in our latest projections. We have published similar reports on a decennial basis in the past following the reconciliation and rebasing of population estimates.
Figure 1 show that projections from 2006-based onwards generally follow the estimated population increase closely.
Figure 1: Total population estimates compared with projections by UK country, 1971-based to 2022-based projections
Source: mid-year population estimates and national population projections from the Office for National Statistics
We produce assumptions for future levels of migration by reviewing what has happened in the past and modelling plausible future scenarios. We consult with a panel of independent academic experts working in the field of demography to discuss the possible forces that may influence future demographic behaviour.
The migration assumptions are not a forecast or prediction of future migration levels; they should be interpreted as a potential scenario in which future net international migration averages at a certain level.
There has been substantial change in international migration over recent years. This has been reflected in the changing patterns of age and sex profiles of international immigration and emigration. The migration component within the National Population Projections system has become larger over recent projections, as the long-term assumption has increased.
We used a 10-year average of international migration (for the 10 years ending mid-2023) to set the principal long-term international migration assumption. Four variant projections have been produced to show what might happen to the UK population if international migration is higher, lower, if there is a faster decline in net migration based on the types of migration over recent years, and if there is no international or internal migration (from the base year); these are all compared with the principal assumption.
Migration assumptions are initially set at an aggregate level for inflows and outflows. Single year of age and sex distributions are then generated and are applied to the assumed aggregate totals, using data from the five years prior to the projections base.
Our latest publication on childbearing for women born in different years, England and Wales: 2023, was released on 2 April, and shows the changing composition of families over time, comparing the fertility of women of the same age and the number of children they have had. The focus is on the fertility patterns of women born in 1978 and compare them with past and projected future generations; this is the most recent cohort for which we have observed completed family size data. For the first time ever, we have published fertility rates using data from the 2022-based national population projections (NPPs) principal projection for England and Wales.
Women in England and Wales who were born in 1978 have an average completed family size of 1.95 children, which is the highest average since women born in 1961; however, this is a lower average when compared with 2.04 children for their mothers’ generation (assumed to be those born in 1951).
Women born in 2007 (now 18 and considered to be the daughters of those born in 1978) are projected to have smaller families than their mothers, with an average completed family size of 1.52 children; this estimate uses the 2022-based principal national population projections.
In October 2024, the ONS published an article looking at how the fertility rate is changing in England and Wales, which highlights that babies are increasingly being born to older mothers. One possible element contributing to this is the rise in participation in higher education, particularly for women. For example, higher education percentage in England by age 25 for females was 54.9% for 2022/23. Putting that in context of the time series, the latest cohort we can report participation by age 25 for is the 15-year-olds from 2012/13, and for this cohort CHEP-25 was 49.0%, an increase of 10.2 percentage points compared to the 2001/02 cohort.
In our article “Milestones: journeying through modern life”, we reference that women start full-time work later than men, with a potential reason being that more women participate in higher education than men. In the most recent figures, 80.2% of women aged 25-34 in the UK were employed (compared to 87.8% of men). Many milestones, such as moving out of the family home, getting married for the first time and buying a home, are happening later in life compared to 2011 or before.
As discussed at the session, the ONS has not completed work on how far these socio-economic factors, such as inability to buy or rent a property until later in life, impact the fertility rate. However, you may be interested to consider academic literature on the topic, such as the positive correlation between education and fertility intentions in Europe (2014) and the recent decline in period fertility in England and Wales(2022).
The ONS publish an analysis of population estimates tool for the UK, allowing users to examine the components of change and view the longer-term impact of different levels of migration on age distribution.
Reviewing the time period since the UK left the EU (implemented from 31 January 2020) (noting this period covers changes to migration during the pandemic), it shows that the higher levels of net international migration in the year to mid-2022 and mid-2023 appear to have stalled the rise in median age. In the long run, with net inward migration, all remaining migrants age. Figure 2 details the age distribution as a percentage of England and Wales population for net international migration for 2023.
Figure 2: International migrants as a % of total population, by age, for England and Wales
Source: Office for National Statistics
The ONS has published estimates of the population of England and Wales by country of birth and passports held based on data from Census 2021. This data can be interrogated by age, sex and geography in the Census 2021 Custom Dataset Tool and in the Census 2021 Maps interactive data.
Figure 3 shows country of birth by age for England and Wales. It shows that the greatest numbers of non-UK born are in the working ages. In the peak working ages of 20-49, just over one in four people were born outside the UK. It is also worth noting the sizeable numbers approaching pension age. Many of the young children will be born to migrants. In 2023, 37.3% of live births were to parents where either one or both were born outside the UK, an increase from 35.8% in 2022.
Since Census 2021, there has been net migration of about 1.5m. Our latest estimate of the population of England and Wales was the year ending June 2023 and includes 11,439,000 non-UK-born people; of which EU-born was 3,395,000 and non-EU-born was 8,044,000.
Figure 3: Age distribution by country of birth and sex, England and Wales
Source: Census 2021 custom table builder, ONS
The Department for Work and Pensions uses ONS data to publish statistics on the economic labour market status of individuals aged 50 and over by five-year age bands and gender. Their latest release was in September 2024, using April-June 2024 data.
In that release, they concluded that from 2019 to 2023, the employment rate of older adults decreased each year from a record high in 2019 of 72.5% to 70.7%. The inactivity rate in 2024 for those aged 50 to 64 continues to remain higher than the pre-pandemic rate, which was 25.5% in 2019. Moreover, the economic inactivity rate for women aged 50 to 64 remains statistically significantly higher, at 31.3% in 2024, when compared to men of the same age (23.2%).
As discussed during the session, there is no clear evidence as to whether older workers are more productive. Age can be a proxy for work experience, where older workers might be more productive because of their greater experience. However, younger workers are typically considered more dynamic. This might lead to better matching between workers and jobs, which could improve productivity.
The ONS is in the early stages of developing a Linked Employer-Employee Dataset (LEED) that will allow researchers to improve our understanding of how workers move between firms throughout their lives, and the relationships between employee and firm-level outcomes such as wages and productivity. We will keep the Committee updated as this work progresses.
Office for National Statistics
May 2025
Dear Mr Griffiths,
I wanted to follow up on my letter to the Committee of 21 October relating to quarterly growth data for Wales.
As you will be aware, the Office for National Statistics (ONS) made the decision to pause the publication of our Quarterly Regional GDP (QRGDP) publication due to concerns raised by users regarding the quality and volatility of the estimates. In the meantime, in agreement with the Welsh Government, we have continued the production and delivery of Welsh Short-Term Indicators (WSTI) to provide quarterly data for Wales.
The ONS have been working with the independent Economic Centre of Excellence (ESCoE) to review the methods for QRGDP. Their report has now been published, and includes several short-term and longer-term recommendations to improve these key statistics.
I can confirm to the Committee that the ONS plans to take on many of these recommendations immediately, which will allow us to reinstate quarterly estimates of regional GDP in an improved form. We will recommence publication of these figures for Wales later this year. Further information on our plans for reintroduction are detailed in a blog.
Yours sincerely,
Professor Sir Ian Diamond
Dear Dame Meg Hillier,
Thank you for your letter of 26 March. Please find in the enclosed annex answers to your questions relating to Office for National Statistics (ONS) economic publications. As I committed in my letter to the Committee on 3 March, I also enclose an update on our plans for the Transformed Labour Force Survey (TLFS).
The ONS continuously improves methods and processes to ensure that our statistics are as accurate, timely and granular as possible and this includes thorough quality assurance. The
nature of statistics and our modernisation work to move off old technology and future proof delivery helps identify quality improvements. We encourage colleagues to raise issues and highlight any concerns with data. Where issues are identified, we communicate these as soon as we can, in line with the Code of Practice for Statistics. We work closely with statistics users and stakeholders on our methodological improvements; where there is not a consensus, we set this out transparently and welcome feedback.
Work to advance a programme of improvements to our labour market statistics continues to be our highest priority given their importance for economic decision making. We have successfully tested an experimental, shortened TLFS questionnaire and undertaken quantitative and qualitative research and methodological development, working closely with external experts and in partnership with our main users. Citizens are at the centre of the new design, which aims to address the quality issues communicated in previous updates by improving completion rates, representativeness, and data quality. The design and implementation approach have been endorsed by Professor Ray Chambers, Professor James Brown, the Labour Market Technical Group and Stakeholder Advisory Panel. The Stakeholder Advisory Panel includes representatives from the Bank of England, HM Treasury and the Office for Budget Responsibility, as well as independent experts.
The new design comprises a short longitudinal ‘Core’ labour market-focused survey, which takes on average 15 minutes to complete and is delivered online first, supplemented by targeted telephone or face-to-face contact for non-responders. This will be complemented by a separate cross-sectional ‘Plus’ survey to provide wider socioeconomic, household and local data. An article and technical report have been published today which provide the evidence for the new design.
Work is already under way to make the new TLFS design operational, with introduction planned across the second half of 2025. We will carry out a readiness assessment in collaboration with main users in July 2026, aiming for transition of our published headline labour market statistics in November 2026, though transition timing will be data-led and could be in 2027 if our assessment, or user needs, require more data to be collected and assessed.
The Labour Force Survey (LFS) will continue as the lead measure while further development of the TLFS takes place. The initiatives and improvements made to collection, methods, and communication have led to LFS quality improvements, including quarterly person data reweighted back to 2019 using updated population estimates in December 2024; achieved individual responses to the LFS (UK including imputation) have now increased to 63,069 in October to December 2024 from 44,238 in July to September 2023, with further increases expected over the coming months.
On 7 April, the Office for Statistics Regulation (OSR) published an interim report on their systematic review of ONS economic statistics. We recognise and share their concerns about data quality and are addressing these as a matter of urgency. Our new Strategic Business Plan published in early April includes a renewed focusing of resources on our core economic and population statistics.
I am copying this letter to Simon Hoare MP, Chair of the Public Administration and Constitutional Affairs Committee.
Yours sincerely,
Professor Sir Ian Diamond
Two separate and unrelated errors in UK trade statistics were recently identified during our routine quality assurances processes, one related to trade in goods data delivered to the
ONS by HM Revenue & Customs (HMRC), and one related to trade in services data processed by the ONS. Both errors were fully corrected on 28 March 2025 as part of the postponed UK Trade release, which now resumes its regular publication schedule, as well as being incorporated into the Quarterly National Accounts and the Balance of Payments. Additional quality assurance procedures, such as further congruence checks, have been put in place to reduce risk of re-occurrence.
HMRC trade data and ONS trade data are published on different methodological bases: HMRC report trade based on goods physically moving across the UK border (known as a “physical movement of goods” basis) and the ONS report trade based on how goods change ownership between residents of different countries, which may involve the goods not physically crossing a border (known as an “economic ownership” basis). This difference in methodological approach complies with international standards. As a result, the monthly data will always differ.
When HMRC delivered the annual microdata to the ONS in December 2024, this was compared with the monthly deliveries as part of our routine quality assurance. A discrepancy was identified relating to the January 2023 reference period onwards, which was escalated to HMRC. Working with HMRC to understand the cause of the discrepancy and whether an error had occurred, HMRC determined that some imports data related to a specific Customs Procedure Code had been erroneously excluded from datasets sent to the ONS. The issue was caused by a technical change being implemented in error to the long-standing process used for extracting imports information shared with the ONS.
HMRC resolved the cause of the error in the data feed and provided the ONS with the correct data on 22 January 2025 for periods January 2023 to November 2024 (and on 18 February 2025 for period December 2024). On receipt of the data, we undertook further processing to bring it onto the required methodological basis. Once the indicative impacts of the error were understood and could be shared with users, this error was communicated by a public notice on 13 February 2025, in compliance with the Code of Practice for Statistics. The Code states that users should be promptly notified of errors or revisions, and that ‘corrections that result from errors, should be explained alongside the statistics, being clear on the scale, nature, cause and impact’.
Trade is one of the components within the expenditure measure of GDP. Due to the integrated nature of the National Accounts, the earliest a correction could be made was in the Balance of Payments and Quarterly National Accounts releases which were published on 28 March 2025. In light of the trade in goods error and reference periods impacted, the ONS exceptionally updated the National Accounts revisions policy to allow revisions back to Q1 2023 in the National Accounts publications.
A separate error was identified in our International Trade in Services (ITIS) survey results processing system, which impacted services imports and exports estimates from 2023. The error was identified as part of our quality assurance of the trade in services data feeding into National Accounts, when large data movements were identified following results processing. Due to the scale of the revisions, we undertook a deep dive into our systems which identified that some data related to some of our quarterly survey respondents had been erroneously excluded. This was confirmed as an error on 12 March 2025, 2 days prior to the announced publication date. The system issue was promptly rectified, with further processing required to re-run all affected reference periods and bring through all relevant data. The error was announced by a notice published on 13 March 2025, which included indicative impacts of the trade in services error, as well as communicating the decision to delay the 14 March 2025 monthly UK Trade bulletin.
This enabled us to bring all corrected trade data for both goods and services together on 28 March 2025 at the same time as the Balance of Payments and Quarterly National Accounts releases, the earliest a correction could be made in line with the National Accounts revision policy.
Several business prices statistics, including the Producer Price Index (PPI), Export Price Index (EPI), Import Price Index (IPI) and Services Producer Price Index (SPPI), collectively referred to as the Producer Price Inflation (PPI) statistics, have been affected by an error with the way certain year-to-year linking methods were applied to the underlying data. This issue was identified as part of an ongoing programme to modernise the ONS’s statistical processing systems. Consumer prices series (CPI, CPIH and RPI) are completely unaffected.
The weights for business prices series used to be updated every five years to reflect changes in the economy. Starting with the publication in November 2020, these statistics were moved to an annual chain-linking methodology, which is the method of updating weights on an annual basis and statistically linking them to produce a time series which reflects changing sales patterns more quickly than under the five-year method. This move to increase accuracy and reliability was implemented alongside several other related methodological improvements.
The ONS has recently commenced a programme focussed on modernising our legacy statistical processing systems for business prices. As part of the preparation for this work, in mid-February we identified a potential issue with the chain-linking methods used to calculate these indices, including the treatment of item level price relatives (the ratio of an item’s price at a given time to its price at another time). Additional investigation, with the support of internal and external methodological experts, confirmed that the method had not been implemented as intended in 2020 and did not align with best practice. As soon as this quality assurance was complete, the ONS issued a public notice on 21 March 2025 and made key stakeholders aware of the problem and its expected implications. We subsequently paused the publication of PPI and SPPI statistics to rectify this issue, starting with the publication due on 26 March 2025.
This work was part of a broader work programme by the ONS to improve the quality of our PPI statistics, most recently in response to a suite of OSR recommendations. These have focussed on a number of specific areas, including:
• sampling
• data validation methods
• revisions review
• non-survey data sources
• imputation
• refining published data, and
• updating the Quality and Methodology Information (QMI).
OSR identified, and the ONS agrees, that further investment in business price statistics is needed. There remains a significant element of processing on legacy technology systems, primarily focussed on the processing of the item level price data submitted by our respondents. However, constrained resources may impact the pace at which we can move production off legacy systems.
This problem affects the years from 2008 onwards. However, investigations suggest that the main impact on annual producer price inflation rates was in 2022 and 2023, because of the large movements in relative prices during that period.
As noted in the statement of 21 March 2025, whilst it is too soon to calculate the overall impact, our current assessment is that while the effects are likely to be mixed for different products and industries, we would expect the headline output PPI level to be revised upwards. Conversely, the headline SPPI level is likely to be revised downwards.
The ONS fully recognises the challenges some users will face from the pause in our monthly business prices publications. However, given the number of series affected, and the legacy systems described above, our current corrective action is focussed on two principal workstreams:
• In the short term, we have chosen to prioritise correcting the detailed price deflators which are needed for high priority economic statistics, a substantial proportion of which rely on underlying inputs from PPI, IPI, EPI and SPPI. These include the inputs needed for our 2025 Annual National Accounts (Blue Book and Pink Book) revisions.
• Further ahead, the ONS will look to restart publication of monthly PPI and quarterly SPPI during summer 2025. The longer time required reflects the need for a significant rebuild of a fragile processing system, and time required to do sufficient quality assurance on the outputs.
The ONS is currently consulting actively with experts from our Technical Advisory Panel on Consumer Prices and key stakeholders (both internally to the ONS and externally) and will publish further updates in due course as these two workstreams progress.
Modelling defined benefit (DB) pension wealth is a complex area of economic statistics, particularly given wider changes to the economy and the heterogeneity of public sector pensions given changes to the schemes over time. To accurately estimate current values on future pensions promises both before and after retirement we need to make assumptions and methodological choices. We keep our methods under regular review, to ensure they continue to be fit for purpose should the wider economic or pensions context change.
The ONS commissioned the Government Actuary’s Department (GAD) in 2023 to review the modelling approach for valuation of defined benefit pension wealth as used in the Wealth and Assets Survey (WAS). This review was in response to the changing economic context in the UK, along with user feedback on assumptions and inputs into the DB pensions model, including from the Institute for Fiscal Studies (IFS). As part of this review, the ONS asked GAD to make recommendations on:
• the discount rate to use in the model,
• how increases to pensions should be recognised in the model,
• what review processes would be appropriate to maintain the model going forwards,
and
• valuing defined contribution (DC) pensions in payment wealth using the DB pensions
model.
In line with government user needs, stability was the primary objective, with a secondary objective being consistency in approaches used to determine the value of other types of wealth, and further objectives of practicality, durability, and continuity. Government user need for minimising undue volatility when valuing DB pension wealth was first highlighted to the ONS by WAS consortium members following the 2008 financial crisis. The previous market-based approach for DB pension valuation used in WAS waves 1-2 led to large changes to published pension wealth estimates between survey waves, which did not wholly reflect actual growth in respondents accrued pension amounts or entitlements, and as such more stable “market immune” approaches were preferred.
GAD’s review concluded that no discount rate could give the best outcome against all of the objectives. Consideration of relative priorities led to a recommendation to use a consistent Superannuation Contributions Adjusted for Past Experience ‘SCAPE’-based discount rate in all parts of the pension model. The recommendations were discussed with a range of stakeholders, including the IFS, during the review and ahead of their report. It was not possible to achieve consensus on the methodological approach, however key government users showed consistent preference for stability. Recommendations were subsequently implemented in our 2020-2022 Household Total Wealth in Great Britain statistics, published in January 2025.
We strongly refute the characterisation of this methodological change as ‘an error’, rather that there is a difference in views on the appropriate methods to apply. Further detail around implementation of recommendations and impact on our wealth estimates were published ahead of the statistical release. In line with GAD recommendations, the ONS plans to undertake a full model review of WAS pension methodology every third round and initiate “out of cycle” reviews should major unexpected economic events occur. Meanwhile, we will continue to engage with WAS consortium members and stakeholders via relevant technical and expert user groups.
On Tuesday 1 April, Mary Gregory, Director for Population Statistics, gave oral evidence to the Lords’ Economic Affairs Committee for their inquiry, ‘Preparing for an Ageing Society’. A transcript of which has been published on the UK Parliament website.
On Monday 17 March, Grant Fitzner, Director of Macroeconomic and Environmental Statistics and Analysis at the Office for National Statistics gave evidence to the Home-based Working Committee for their session on the social and economic impacts of working from home.
A transcript of which has been published on the UK Parliament website.
Dear Dame Meg Hillier,
Thank you for your letter of 14 February, following up on our evidence session with your Committee on 4 February. As I mentioned during the session, we are grateful for your interest in this important area of work.
In response to the request in your letter, I can commit to providing regular updates on the progress of the Labour Force Survey (LFS) and the Transformed Labour Force Survey (TLFS), and any emerging issues of note, to both this Committee and the Public Administration and Constitutional Affairs Committee (PACAC). In the first instance, I will write to the Committee with an update following the upcoming decision regarding the future timings of the TLFS.
During the session, I promised to write regarding two further points.
We discussed the efficiencies the Office for National Statistics (ONS) made in 2024. Following clarification from colleagues, I wanted to confirm that by the end of the 2024/25 financial year we estimate that the annual effect of cumulative efficiencies and savings generated across the SR21 period will be £39.2m. This equates to 9.9% of forecast net expenditure estimated at £396m for 2024/25. I would be grateful if the transcript could be updated accordingly.
We also discussed the impact of contacting the public via telephone during the pandemic, the potential of using other contact methods to improve survey response rates and if the ONS requires additional powers to access contact details. The ONS currently uses both mobile phone and landline numbers to contact respondents. The Transformed Labour Force Survey (TLFS) sample of household addresses is telematched using commercially available datasets of mobile and landline numbers. This approach typically provides a phone number of varying quality for approximately 30% of addresses. Email addresses are less useful as they cannot be linked to an address, and we are not assured of their security, so we only use these where they have been provided to us by the respondent during our first interview with them. This enables us to contact them to ask them to complete later waves of the survey.
I am content that the ONS currently has the legislative framework it requires to obtain the data we need to deliver our surveys and contact respondents. Our new Survey Innovation and Research hub will accelerate our work this year to increase response rates and maximise respondent engagement across our surveys.
Thanks again for interest and as I mentioned in the session, I would be very happy to welcome you and your Committee to our office in Newport, Wales.
I am copying this letter to Simon Hoare MP, Chair of PACAC.
Yours sincerely,
Professor Sir Ian Diamond
On Tuesday 4 February, Professor Sir Ian Diamond, National Statistician, Mary Gregory, Director for Population Statistics and Richard Heys, Deputy Director for Productivity, Investment and Research at the Office for National Statistics gave evidence to the Treasury Committee for their session on economic statistics.
A transcript of which has been published on the UK Parliament website.
