Office for National Statistics follow-up written evidence to the Welsh Parliament’s Culture, Welsh Language and Communications Committee’s inquiry on the 2021 Census

Dear Ms Sayed,

Thank you for inviting the Office for National Statistics (ONS) to give evidence to the Committee on 18 April.

At the session, I committed to providing some further information in response to questions around data security. I understand there were also questions on Armed Forces, Volunteering and Income data that time did not allow for on the day.

In response, I attach a brief note which summarises ONS’ current position on these issues.

Yours sincerely,

Iain Bell
Deputy National Statistician and Director General, Population and Public Policy
Office for National Statistics


In December 2017, we published an update on our topic research for the 2021 Census which contains details on our testing and evaluation to date on a number of Census topics.

Armed Forces data

In October 2017, ONS announced that it would recommend the inclusion of a question on the Armed Forces in the 2021 Census for England and Wales. Our research and consultation have established that there is a clear need for information on the Armed Forces and Veteran community.

Central and local government have told us they need information on the Armed Forces and Veteran community to fulfil their commitments under the Armed Forces Covenant. Services and support need to be delivered to the Armed Forces community in areas such as health, housing, qualifications, employment and others. Administrative data provides some of the data required, but not all.

ONS have developed and successfully tested a Census question, which we hope will meet the needs of decision-makers. We therefore intend to recommend inclusion of this topic in the 2021 Census.


We have designed two different questions on volunteering. In both rounds of testing, respondents had difficulty matching their volunteering activities to a response option. Results of the Census Test Evaluation Survey suggest challenges to collect information of sufficient quality to meet the user need. Alongside this, our understanding of user needs for other topics has grown. And so, to manage respondent burden and meet space constraints on the paper questionnaire, we intend to recommend not collecting information on volunteering in the 2021 Census.

We are currently researching how to provide this data by other means. Our economic well-being team are leading an area of work to understand the value of unpaid work, including volunteering.
Valuations of unpaid work are produced in the Household Satellite Accounts which was released in 20164 and provided data from 2005 to 2014. The team also use time-use data to understand the
division of unpaid labour within households and are now planning a new time use survey to further develop and modernise these statistics.


ONS will not recommend that questions about personal income or household income be included in the 2021 Census for England and Wales. Our testing has shown that including a question on income within the Census negatively impacts on response rates, and undermines the quality of data. Instead, we are carrying out research to see if it is feasible to produce income statistics using administrative data.

Our current focus is on producing small area income outputs and understanding the precise user needs for the definition of income. We’ll then extend the research to multivariate outputs.

We are encouraged that our early analysis using administrative data broadly reflects the patterns we expect to see regarding income.

Data access and security

ONS has a strong record in protecting and safeguarding the security of data and information supplied to the Census, not least in its rigorous protection of personal Census information collected over the past 200 years. ONS successfully outsourced census services in 1991 (e.g. publicity, distribution), in 2001 (e.g. postal services, questionnaire printing, questionnaire scanning, data capture and coding as well as the census call centre and helpline) and in 2011 (e.g. publicity, questionnaire printing, postal services, questionnaire scanning, data capture and coding, census helpline, field staff recruitment, payment and training).

The 2021 Census plans to collect the majority of the data using on-line systems with considerably fewer paper forms than in 2011. Outsourced services for a 2021 Census would be conducted in
accordance with government procurement standards and requirements, designed and managed to safeguard the confidentiality of personal information and to deliver value for money. Any companies bidding for work would be subject to the same security requirements as apply to ONS, including those set out in the Statistics and Registration Service Act 2007 (e.g. provisions in s.39) and the Data Protection Act 2018.

The security of Census data is a top priority and ONS has stringent safeguards to protect this data in all our operations. This includes control of physical access to any site or room where the Census data is stored, the secure control of access to Information Technology (IT) systems, personnel security controls to assure the trustworthiness of employees and suppliers working on the Census. All the Information Technology (IT) systems within ONS and its suppliers are designed with security in mind based on UK Government and industry best practice guidelines. Rigorous controls are implemented to protect data during transmission, storage and processing. Specific technical testing is also performed to ensure the systems are built and configured correctly. These security controls are additionally reviewed by the National Cyber Security Centre. The census security programme and its supplier operations activity is managed to the framework of ISO27001 – the internationally recognised Information Security Management Standard.

ONS provides assurance for the trustworthiness, integrity and reliability of our employees and suppliers involved in the Census. The data collected contains sensitive personal information and
ONS has a duty to protect this. A security clearance plays a significant and important role in assessing and managing access to this sensitive information. All staff working on the Census undergo a range of personal checks to validate their identity and check their criminal record. Those employees with access to personal information have an additional national security vetting performed.
ONS tightly controls access to IT systems that hold Census data to ensure that only those employees with the need to access this can do so. The proposals for the 2021 Census ensure that the data
captured electronically will at all times be handled securely. These measures cover the completed questionnaires, the electronic Census data set and all infrastructure relating to the operation of the Census including websites, supplier systems and communications links. Specific governance and processes authorise and manage access to Census data. Protective monitoring of this access
ensures that it is used in accordance with the ONS rules. All of the electronic communications links used for routing personal census information are encrypted.

Our current plans for data collection mean that completed paper forms will be securely scanned and passed to ONS by a supplier operating under ONS oversight. Suppliers will also be used in recruiting the field force and providing services such as the operation of our contact centre. All those working on the Census as employees of ONS or as suppliers or sub-contractors providing services to support the 2021 Census will be security checked and required to sign an undertaking to demonstrate that they understand their legal obligations and will not disclose any information relating to an individual person or a household.

A Data Protection Impact Assessment (DPIA) is a legal requirement of the new Data Protection Act implementing the General Data Protection Regulation, where the processing of personal data is likely to result in a high risk to the rights and freedoms of individuals. A Privacy Impact Assessment (the previous name for DPIAs) was completed for the 2011 Census and published on the ONS website. ONS has produced and published a privacy impact assessment at the initial research stage (The Census and Future Provision of Population Statistics in England and Wales: Privacy Impact Assessment for the Initial Research Stage’, March 2015). The DPIA for the 2021 Census will identify the risks to privacy and assess those risks; detail all our processing activities; ensure that our processing meets the principles of data protection, such as transparency and fairness; ensure that we have undertaken necessary consultation with relevant stakeholders.

Ongoing security reviews are performed on all Census systems to ensure that the security defences remain effective and cyber security with the potential to affect Census data are detected.

Finally, at the core of ONS’ data security is our Five Safes Framework – Safe people; Safe projects; Safe settings; Safe outputs; Safe data. Under the safe people pillar is the Approved Researchers
Scheme. This scheme is used by ONS to grant access to data that cannot be published openly, for statistical research purposes, as permitted by the Statistics and Registration Service Act 2007. To
access data in this way, an individual must hold ONS Researcher Accreditation and have their research proposal approved by the ONS Microdata Release Panel, on behalf of the National Statistician. The processes and criteria used within the Approved Researcher Scheme were revised in 2016. The criteria for accreditation require that all researchers be fit and proper, and their specific research proposals are scrutinised to ensure there is a clear public benefit. Further information about the Approved Researchers Scheme can be found on our website.


Related Links:

Office of National Statistics written evidence to the Welsh Parliament’s Culture, Welsh Language and Communications Committee’s call for evidence on the 2021 Census. (March 2018)

Office of National Statistics oral evidence to the Welsh Parliament’s Culture, Welsh Language and Communications Committee’s call for evidence on the 2021 Census. (April 2018)

Office for National Statistics oral evidence to the Welsh Parliament’s Culture, Welsh Language and Communications Committee’s inquiry on the 2021 Census

On Wednesday 18 April 2018 Iain Bell Deputy National Statistician and Director General for Population and Public Policy, Office for National Statistics and Garnett Compton, Census programme, Office for National Statistics, gave oral evidence to the Welsh Parliament’s Culture, Welsh Language and Communications Committee for their inquiry on the 2021 Census.

A transcript of which has been published on the Welsh Parliament’s Website.

Related Links:

Office of National Statistics written evidence to the Welsh Parliament’s Culture, Welsh Language and Communications Committee’s call for evidence on the 2021 Census. (March 2018)

Office of National Statistics follow-up written evidence to the Welsh Parliament’s Culture, Welsh Language and Communications Committee’s call for evidence on the 2021 Census. (July 2018)

Office for National Statistics written evidence to the Welsh Parliament’s Culture, Welsh Language and Communications Committee’s inquiry on the 2021 Census

Dear Ms Sayed,

I write in response to the Culture, Welsh Language and Communications Committee’s call for evidence on the 2021 Census.

As the Committee are aware, the Office for National Statistics (ONS) is the UK’s National Statistical Institute, and largest producer of official statistics. We aim to provide a firm evidence base for sound decisions, and develop the role of official statistics in democratic debate.

We are also responsible for the Census in England and Wales, with the next census to be carried out in 2021. In advance of appearing before the Committee in April to answer your questions, the below provides some initial information for consideration.

Census consultation to date

Question development for the 2021 Census started in June 2015 with the 2021 Census topic consultation, asking stakeholders for views on our initial thoughts on which topics we should ask questions on in the 2021 Census. 1095 stakeholders responded to the consultation indicating their need for data on different topics, expressing needs for information on new topics such as the Armed Forces community, sexual orientation and gender identity, and outlining areas where changes made could help better meet user needs. Following the topic consultation, we published topic-specific reports outlining our next steps, and developed testing plans to research the needs identified.

Further consultation has been held around topics where greater needs for change or development were identified. We have also held public events such as a series of roadshows (July 2016) and adhoc meetings with interested parties including All Party Parliamentary Groups, community groups and charities. Most recently, ONS held a stakeholder forum in London on 13 December 2017. At the forum, we discussed needs and research on the topics of gender identity, sexual orientation and ethnicity. We will be hosting another forum on 23 April in Cardiff to discuss the topic of ageing.

On 28 February, we launched a public consultation on 2021 Census Output content to help us understand what statistical products our users need from the 2021 Census outputs, and to help prioritise our future research. This is open for views until 23 May.

Achieving a successful census in Wales

ONS engages with Welsh users and stakeholders through a number of different channels to ensure that the needs of Welsh communities and users of statistics are fully represented and taken into account.

There are three main areas we have engaged on:

1) Ensuring the questions cover the needs of Welsh users;
2) Successful operational delivery within Wales; and
3) Ensuring the outputs meet the needs of Welsh users.

All three of these activities are covered by the Welsh Census Advisory Group (CAG). This is chaired by Glyn Jones, Chief Statistician for Wales, and includes stakeholders from other government departments, universities and non-profit data users. The group’s remit covers design and delivery issues as they relate to data production and data use. The CAG formally meets twice a year but members are regularly consulted and updated throughout the year between meetings.

At the last meeting of the CAG in January 2018, ONS updated the group on progress to date, and sought input from group members on topics, developments in geography and results of the 2017 Census test.  Most recently, group members have been invited to respond to the outputs consultation that we launched in February.

Question design

As well as engaging stakeholders through the CAG, in November 2017, ONS and the Welsh Government jointly hosted a ‘Welsh Language in the 2021 Census’ stakeholder event. Attendees included representatives from Welsh Councils, the Welsh Language Commissioner and Welsh Language interest groups. Presentations from ONS and the Welsh Government were followed by a Roundtable discussion on the Welsh language, which considered the format and routing of the questions, and allowed the group to consider how the data may be used, and potential limitations. Their views and feedback are being considered, alongside testing and evaluation results, to propose the recommendations for the 2021 Census. The group may be contacted again in the future for matters relating to Welsh language in the Census.

Operational delivery

The CAG is also utilised to support strategic and operational development of the 2021 Census. A key example of this was the provision of information relating to religious communal  stablishments in Wales. This information has been used to inform the strategic and operational approach to communal establishments more broadly.

In addition to the CAG, we use the Census Liaison Operational Management Group (OMG) to address operational issues with ONS and its members which include Ceredigion and Cardiff County Councils.

Meeting user needs

Users from the Welsh Government recently expressed interest in the 2017 test results. The Welsh Statistical Liaison Committee and the Third Sector User Panel at Welsh Government were presented with this information last year. Work with the CAG has enabled us to build relationships with these groups, and has helped us understand the specific needs of the users that these groups represent.

More widely, as in 2011, we are currently undertaking programmes of work to engage at local authority level, and a census community engagement programme. To ensure we are able to engage with users effectively, we provide information and promotional materials in Welsh and are also developing a bilingual census logo.

Welsh Language Questions

In 2011, language data was collected through questions on Welsh skills, Main language and English language proficiency (examples at Annex A). Main language and English proficiency were new questions in 2011. The aim of the language questions is to identify the size of the population for whom English is not their main language, and their level of proficiency in English. This data is used to inform policy development, local planning and service provision such as education, health and local services.

The structure of the language questions was as follows:

• Welsh skills was collected only in Wales and the question space was left blank in England.
• Main language response options were slightly different in England and Wales, with the ‘English’ tick box in England replaced by ‘English or Welsh’ in Wales to capture both national languages in Wales. The Welsh language version reads ‘Cymraeg neu Saesneg’ (‘Welsh or English’) to reflect the version of the form chosen.
• The English proficiency question was identical in England and Wales.

During question testing, an option was tested where the main language response options ‘English or Welsh’ / ‘Cymraeg neu Saesneg’ was split into two separate tick boxes. Results of the testing
showed that respondents struggled to answer, particularly amongst the Welsh speaking community. Results of the research were shared with Welsh language stakeholders at the event held in
November 2017. The Welsh language stakeholders discussed the results and agreed as a group that the response option should not be split. They agreed that Welsh skills data would be best placed for monitoring the Welsh language.

The need for language sub-topics was identified in the 2021 Census topic consultation held in 2015. Some stakeholders did express an interest in first/second, ‘native’ or additional languages but the requests did not evidence a strong enough user need to pursue a change. Data quality was not raised as an issue following on from the 2011 Census. All work so far has largely focused on user need but further testing and user research is planned to finalise all of the question wording, particularly focused on the online census questionnaire. As a result of testing and feedback, we are proposing to use the same language questions from the 2011 Census in the 2021 Census.


The Office for National Statistics (ONS) is only responsible for the Census in England and Wales; the censuses in Scotland and Northern Ireland are devolved responsibilities and are carried out by
National Records of Scotland and the Northern Ireland Statistics and Research Agency. We work closely with the Devolved Administrations to ensure that results from each of the censuses are as
comparable as possible. Although detailed arrangements may vary, each country will follow the same basic procedures with the publication of initial proposals being followed by the required secondary legislation.

For England and Wales, the Census Act 1920 provides for a census to be taken, however each census can only be carried out following approval of secondary legislation – the Census Order (affirmative procedure) and Census Regulations (negative procedure), which set out the questions to be asked and the procedures for collecting the information. Welsh Ministers must be involved in respect of explicit consent to the order and laying of separate regulations in the Welsh Assembly.

Secondary legislation is preceded by a White Paper which traditionally sets out the proposed topics for inclusion in the census questionnaire and proposals for how the census will be conducted. The most significant changes this time being that the census will be predominantly online and the greater use of administrative data to pave a way to meet the Government’s ambition that censuses after 2021 are conducted more frequently, using existing data.

Updates on other topics

Many of the core issues about what to ask in the 2021 Census have already been determined through the topic consultation in 2015 and subsequent research since 2016. Testing has taken place in England and Wales, in both the English and Welsh language. The latest update, where a final proposition was reached, was our announcement that we will be proposing a question on Armed Forces veterans to provide information to help public authorities meet their obligations under the Armed Forces Covenant. This was followed by the 2021 Census topic research report in December 2017.

We have identified a clear need for improved information on sexual orientation and gender identity. This is especially in relation to policy development, service provision and fulfilling duties under the Equality Act 2010. Data on the Lesbian, Gay, Bisexual and Transgender (LGBT) population would provide evidence on the extent of inequalities, discrimination and disadvantage, which in turn would help to target and improve policy making, particularly in health services, education, employment, housing, social services and homophobic crime reduction services for LGBT groups.
We are still considering whether and how to collect information on gender identity, alongside continuing to collect information on male or female. This is particularly complex in meeting a respondent need for gender identity, a user need to measure the size of the trans population while ensuring an accurate estimate of the male and female population. Our research so far gives us confidence that collecting gender doesn’t have a negative impact on collecting information on male and female. We also know that there is a strong information need for separate information on the trans population.

Further testing is planned to refine the question design and inform our recommendation about the inclusion of such a question or questions in the 2021 Census. To be clear, we have never suggested that people would not be able to report themselves as male or female. We have and will continue to collect this vital information.

Users expressed a wide range of demands for data on ethnicity and religion. Based on user need, we have narrowed this down to four potential additional tick boxes to the question asked in 2011 –
Jewish, Roma, Sikh and Somali. We continue to engage with the relevant communities on the acceptability or otherwise of including such additional tick boxes. We are also undertaking further
research to assess whether the inclusion of new categories will collect sufficient quality information to meet the user need and that our conclusions are compliant with our legal obligations. A successful census test was carried out in 2017 including areas within Powys, to test the impact on response of including a sexual orientation question and to assess the new technologies and processes required to run a predominantly online census. We are planning for a rehearsal of around 100,000 households in 2019 before scaling up to 26 million households in 2021. The rehearsal will be run in both England and Wales.

ONS will make its recommendations to government on 2021 Census content later this year. Our recommendations will be based on our considerations around the evidence of user need, public
acceptability of proposed questions, and our ability to devise questions that collect good quality information to meet the user need and our legal obligations.

I look forward to answering your questions and elaborating on the above in April.

Yours sincerely,

Iain Bell
Deputy National Statistician and Director General, Population and Public Policy
Office for National Statistics



Annex A Examples of the 2011 Census form

The main language question is used to route respondents with the national language as their main language past the ‘English proficiency’ question.

Examples of the 2011 Census form

Related links:

Office of National Statistics oral evidence to the Welsh Parliament’s Culture, Welsh Language and Communications Committee’s call for evidence on the 2021 Census. (April 2018)

Office of National Statistics follow-up written evidence to the Welsh Parliament’s Culture, Welsh Language and Communications Committee’s call for evidence on the 2021 Census. (July 2018)