Overview
The Office for Statistics Regulation (OSR) is responsible for assessing how well the UK censuses meet the professional standards outlined in the statutory Code of Practice for Statistics.
NISRA is committed to ensuring that the results of Census 2021 are accurate, reliable, and fully compliant with the Code, as overseen by the UK Statistics Authority.
The OSR welcomes feedback from users and stakeholders on their experiences of Census 2021 in Northern Ireland. You can share your views via the Office for Statistics Regulation website.
NISRA sincerely thanks all census data users who have engaged with the OSR during its assessments. We value the scrutiny and constructive feedback provided, and we extend our appreciation to the OSR for its fair and balanced findings.
Looking ahead, NISRA will continue to collaborate with the National Records of Scotland (NRS) and the Office for National Statistics (ONS) to address the OSR’s recommendations and drive continuous improvement in census delivery.
Assessment process for Census 2021
The Code of Practice for Statistics sets out the detailed principles and practices that producers of official statistics must follow when compiling and releasing data. By adhering to the Code, government statisticians help ensure that the statistics they publish are trustworthy, high quality, and serve the public good. This compliance builds confidence for users of statistics and citizens in the value and integrity of official statistics.
The OSR conducted its assessment in three phases:
- Phase 1 focused on lessons learned from the Phase 3 assessment of Census 2011. It evaluated compliance with the three pillars of the Code - Trustworthiness, Quality, and Value - during the planning and development stages.
- Phase 2 again assessed compliance with the Code, with increased emphasis on Quality and Value as the census offices moved closer to census day.
- Phase 3 took place after the publication of census outputs. It involved evaluating the outputs in light of user feedback and assessing how well they met user needs.
Phase 1
NISRA Phase 1 report
On 12 June 2019, NISRA produced a report 'How NISRA is ensuring that Census 2021 will serve the public'.
The report sets out the processes and procedures implemented by NISRA for Census 2021 to ensure that the resultant statistics are trustworthy, high quality and of public value.
Similar reports have also been published by:
- ONS - How the Office for National Statistics is ensuring the 2021 Census will serve the public
- NRS - How the National Records of Scotland is ensuring Census 2021 is trustworthy, high quality and of value to users
OSR response to NISRA Phase 1 report
The OSR assessed how the three UK census offices - NISRA, NRS, and ONS - would ensure that the 2021 Censuses would effectively serve the public.
Its report, 2021 Censuses in the UK – Preliminary Findings, published on 4 October 2019 alongside a letter to the census offices, detailed the extent to which their planning, engagement, and development activities complied with the Code of Practice for Statistics.
The report also included recommendations for each office to help maintain National Statistics accreditation for their census outputs.
NISRA response to OSR Phase 1 findings
The three UK census offices - NISRA, NRS, and ONS - have worked collaboratively, where appropriate, to address the findings identified by the OSR. These efforts aim to enhance the public value, quality, and trustworthiness of data and statistics from the 2021 Census across the UK.
NISRA’s response is detailed in the report Census 2021 - Response to Actionable Findings from Phase 1 of the National Statistics Accreditation, published on 15 June 2020.
Similar reports have also been published by:
- ONS – Response to Actionable Findings from Phase 1 of the National Statistics Accreditation
- NRS – Response to Actionable Findings from Phase 1 of the National Statistics Accreditation
OSR review of NISRA actions
The OSR reviewed the actions taken by NISRA in response to the actionable findings from Phase 1 of the National Statistics Accreditation process.
In a letter published on 11 September 2020, the OSR highlighted:
- noteworthy actions taken by NISRA
- areas requiring further attention
NISRA is committed to transparency and continuous improvement, and we continued to report on our progress as we moved into Phase 2 of the accreditation process.
Phase 2
NISRA Phase 2 report
The Phase 2 report, How NISRA is Ensuring Census 2021 Will Serve the Public Good: January 2021 Progress Update, published on 28 January 2021, provided an update on NISRA’s progress toward achieving National Statistics accreditation.
The report outlines:
- NISRA’s ongoing response to the OSR’s actionable findings
- How Census 2021 operations in Northern Ireland align with the three pillars of the Code of Practice for Statistics
- The impact of the COVID-19 pandemic on Census 2021 planning and delivery
Similar reports have also been produced by:
- ONS - How the ONS is ensuring Census 2021 will serve the public good: January 2021 progress update
- NRS - National Statistics Accreditation Phase 2 Evidence Report January 2022
OSR Phase 2 report
On 17 November 2021, the OSR published its report, Assessment of Compliance with the Code of Practice for Statistics – 2021 Census in Northern Ireland.
The assessment highlighted the success of the data collection operation and outlines the remaining steps required for the 2021 Census outputs to achieve National Statistics accreditation. The OSR is expected to make its accreditation decision before the first outputs are released in summer 2022.
Similar assessments have been published for other UK censuses:
- ONS - Assessment of Compliance with the Code of Practice for Statistics – 2021 Census in England and Wales
- NRS - Assessment of 2022 Census in Scotland
National Statistics designation for Census 2021 outputs
On 23 May 2022, the OSR confirmed the designation of National Statistics for the outputs from Census 2021 in Northern Ireland.
In September 2023, the OSR introduced the term ‘Accredited Official Statistics’ to replace the previous designation of National Statistics, aligning with updated terminology across the UK statistical system.
NISRA remains committed to engaging with census data users through ongoing consultation and collaboration, ensuring the greatest possible value is derived from Census 2021 data.
Phase 3
OSR Phase 3 report
On 11 February 2025, the OSR published its report, Assessment of Compliance with the Code of Practice for Statistics: 2021 Census in Northern Ireland. The report assessed how effectively NISRA’s census outputs have met user needs and revisited the requirements set out in the OSR’s Phase 2 report from 2021.
The OSR confirmed that the Census 2021 statistics for Northern Ireland comply with the Code of Practice for Statistics, demonstrating the highest standards of trustworthiness, quality, and public value.