1. Introduction
A census usually takes place once every ten years and is the largest and most complex statistical exercise undertaken in Northern Ireland. Census statistics are a vital source of information, and are widely used by government, public bodies, academia, commercial businesses and others to develop policies, allocate resources and help deliver services.
2. Purpose
The last census in Northern Ireland was taken on 21 March 2021. This report provides a factual account of how it was conducted and sets out a record of key elements associated with the operational delivery of the census. It is intended that this report will provide useful reference material to departments/agencies in major projects that require widespread engagement with the public and contain a significant digital element. This report will also help users of census statistics understand how those statistics were collected.
3. Impact of COVID-19
While some of the plans for the delivery of the census had to be changed due to the pandemic, this report does not detail these changes, but rather outlines what actually happened. However, it is important to recognise, whilst reading this report, the challenge of undertaking census data collection during the pandemic.
4. Roles and responsibilities
Census Office, part of the Northern Ireland Statistics and Research Agency, an executive agency within the Department of Finance, has responsibility for delivering the census in Northern Ireland. Census Office staff worked closely with colleagues from the Office for National Statistics (ONS) in England and Wales on all aspects of the census operation.
In addition, Census Office staff worked with colleagues from within the Department of Finance, and across the Civil Service, as well as organisations from the public, private and voluntary sectors. A wide range of external suppliers were also key to the successful delivery of the census operation, and these are listed at Appendix A. The input and assistance of all stakeholders, suppliers and contributors to Census 2021 is noted and appreciated.
5. Definitions
A list of the terms and definitions unique to census operations can be found at Appendix B.
6. Operational areas
6.1. Stakeholder engagement and communications
The Stakeholder Engagement and Communication (SEaC) team within Census Office was responsible for the development, implementation, management and delivery of communications and public engagement for Census 2021. In undertaking this work, two overarching aims were critical:
• to educate the population on the value of the census and its importance;
• to explain and advertise the ways to make a census return, in order to make it easier for everyone to participate.
These were underpinned by a series of key objectives, one of which was ‘to promote a digital first approach’.
6.1.1. Advertising
From the outset, Census Office recognised the importance, not just of raising awareness of the census, but also of highlighting the benefits of completion. In partnership with the Government Advertising Unit, Census Office implemented a full advertising campaign, using a wide range of approaches, including TV, radio, press, digital and outdoor. This advertising and the communications approach contributed to increased awareness of the census from 70% in 2019 to 99% by 2021. The campaign had five phases, and contained key messaging with changes in focus as follows:
Table 1: Census 2021 advertising phases
| Phase | Objective | Date from | Date to |
|---|---|---|---|
| 1 | Awareness: The census is coming | 22-Feb | 05-Mar |
| 2 | Motivation: The census is almost here | 06-Mar | 18-Mar |
| 3 | Act now: Census is here | 16-Mar | 21-Mar |
| 4 | Reminder: There’s still time to complete your census | 22-Mar | 11-Apr |
| 5 | Obligation: Complete it now | 12-Apr | onwards |
6.1.2. Stakeholder engagement
Census Office developed a comprehensive database of stakeholders, including groups and organisations across Northern Ireland – local councils, the police, political parties, public representatives, schools, churches, large employers and voluntary groups. Prior to and through the operational data collection period, Census Office worked closely with these stakeholders, to promote, raise awareness and highlight the benefits of completing the census. Census Office also developed a database of local stakeholders for each council area, to help facilitate Census Area Managers (CAMs) in their engagement with community groups.
A range of posters and leaflets were printed and circulated to stakeholders, with a view to displaying within their premises (for example, in COVID-19 vaccination centres). Other promotional material was also provided to schools and other groups. Not surprisingly, due to COVID-19 restrictions the vast majority of stakeholder engagement was carried out online.
6.1.3. Schools
A dedicated schools programme entitled ‘Let’s Count’ was developed in partnership with the Council for the Curriculum, Examinations & Assessment (CCEA). Its aim was to inform children about the census, contribute to their learning and use the power of children to get adults in their households to fill out the census form. The pupil resources were made available at CCEA Let’s Count. There were more than 9,000 views of the Census at Schools pages. The programme was impacted by the pandemic with schools being closed and home schooling in place. However, the resources were communicated to primary school teachers through a series of targeted mail drops, social media posts and an item on the education communications network news desk.
6.1.4. Communication
At the start of the census collection period, a press conference was held and a number of press releases were published throughout the operational period. The assistance of the local media throughout the census is noted. The census was also running in England and Wales at the same time as Northern Ireland, and although Northern Ireland had its own communications plan, there was a natural overlap, with the underlying message around the census being reinforced.
Key communication features included the Census NI website, social media @NICensus2021 and the call centre (0800 328 2021). These resources were kept up to date with relevant and timely information. The new social media channels (Facebook and Twitter) were vital in posting regular updates and reinforcing key messages. All of this activity had the primary aim of encouraging the public to complete their census return (see Appendix C for social media and website activity).
6.1.5. Printing and digital products
Census Office developed a co-ordinated and controlled list of public products (for example, leaflets, letters etc.). This was managed centrally to ensure consistency of presentation and tone, and to provide a record of all printed and digital products used in connection with the census.
6.1.6. Accessibility
One of the keys to a successful census was ensuring that the completion process was easily accessible to all. This included making available a range of accessibility products, the aim of which was to provide help and guidance.
Accessibility products in large print, Easy Read, Braille, as well as British and Irish Sign language were produced. This guidance was primarily to help respondents understand the census questions and then complete the questionnaire.
Accessibility products were available to download from the Census NI website, or upon request from the contact centre.
6.2. Address register
Central to the operational design of Census 2021 was the development of a comprehensive address register, essentially a database of all addresses in Northern Ireland (households and communal establishments).
The address register was a key tool in guiding census data collection and four key functions stemmed from it:
- to facilitate the posting out of letters/forms to households and communal establishments;
- to facilitate the process for following up non-responders by identifying addresses for which no return had been received;
- to provide address ‘lookups’, for the online questionnaire, to facilitate responses to address questions. The whole address register was used for this aspect and included invalid addresses for example, derelict, demolished and non-residential/commercial addresses to aid completion of questions like ‘address 1 year ago’ and ‘workplace address’;
- to assist with the ‘address resolution’ function. This function managed the validation of new addresses added to the register, and the process for switching off addresses identified as invalid by census field staff.
6.3. Data collection services
A major focus of Census Office in the run-up to Census 2021 was developing the systems and services required to collect data securely and efficiently from the general public. In Census Office this was managed through the Data Collection Services (DCS) team. This team worked closely with colleagues in ONS and through a range of external suppliers of services.
The main areas and processes delivered included:
• Print and post out (PPO) – the management of the printing and posting out of all initial contact letters (675k), reminder letters (250k), door-drop postcards (c.2.5m) and all materials requested by the public during the operation (samples of some of the various communications can be found at Appendix D);
• Electronic questionnaire (eQ) – this involved the delivery of Northern Ireland specific questionnaires (both through ONS managed systems and through local systems developed for communal establishments). As the eQ was the main public facing element of the census data collection process, a significant amount of time was taken for the design of the system and subsequent testing. This system was developed in-house by ONS working closely with Census Office staff, and was a key success element of the census. Whilst the eQ system was initially developed prior to the pandemic, a number of updates to improve user experience were required at a late stage. This requirement, primarily due to the impact of the pandemic, brought significant challenges to the delivery timeline;
• Questionnaire management (QM) – print and post out of initial contact paper questionnaires (168k), reminder paper questionnaires (80k) and questionnaires requested by the public during the operation (50k). This service included the post-collection scanning of all returned paper questionnaires, capture of raw data from paper questionnaires and statistical coding of both the paper and online returns;
• Paper questionnaire return service (PQRS) – receipting of all returned paper questionnaires and transmission of this receipting information to the central response management system. This service also included delivery of physical questionnaire packs to the data capture centre;
• Contact centre/online help – supporting the public with making their census returns required the design, development and delivery of content and requirements for the contact centre and online help. In total 161,616 phone calls were received by the contact centre – details are shown at Appendix E. Census Office staff developed all the Northern Ireland materials and managed/trained the relevant staff in the delivery of these services;
• Response management – this was a central technology system for the management of data collection developed and managed in-house by ONS. The system allowed live tracking of the status of each census return and of interactions/requests with addresses/householders throughout the operation. This system acted as the basis for management information and informed the decision making process around changes to the interaction with householders during the collection period. In particular, the management information helped inform key decisions in relation to reminder letters and ‘field-work’.
The remainder of this section gives some further information on the level of utilisation of these key services.
6.3.1. Contact centre
• The centre opened for telephone calls from 1 March 2021. The opening hours were 8am to 8pm Monday to Friday (excluding bank holidays), Saturday 8am to 1pm, and 8am to 8pm over census weekend (20 and 21 March 2021). The contact centre provided support and information using various methods, including webchat, webmail, telephone, SMS, online help and an interpretation service via a dedicated language line;
• The contact centre handled a wide range of enquiries, providing help to complete census for households, individuals, visitors, vacant properties or holiday homes, as well as requests for paper questionnaires (PQs), individual forms, continuation forms, large print PQs, Braille and translation booklets. The contact centre service also facilitated householders who wished to complete their census over the phone;
• In total the contact centre dealt with 161,616 calls up to 8 July 2021.
6.3.2. Postal delivery of wave of contact materials
• Pre-delivery postcards were issued to all addresses from Monday 22 February 2021;
• Initial contact paper questionnaires (PQ) (168,000) were issued to a range of addresses across Northern Ireland between 1 and 2 March 2021;
• Initial contact letters (invitation to take part online) (675,000) were issued to the remaining addresses between 3 and 5 March 2021;
• Pre-census day postcards were delivered to all addresses from Monday 15 March 2021;
• Post-census day thank you/reminder postcards were issued to all addresses from Monday 22 March 2021;
• First targeted reminder letter was sent to all non-responders for whom (at 25 March) Census Office had no evidence of a response. This letter landed with 190,000 addresses from Wednesday 31 March 2021;
• Second targeted reminder which included a paper questionnaire to all non-responders for whom (at 13 April) Census Office had no evidence of a response. In total paper questionnaires were issued to 79,000 addresses – the questionnaires landed from Monday 19 April 2021;
• Third and final targeted reminder letter was issued to all non-responders for whom (at 5 May) Census Office had no evidence of a response. In total the reminder was sent to 60,000 addresses – the letter landed from Monday 10 May 2021.
6.3.3. Online system: the electronic questionnaire
• It should be noted that the online system was designed in line with Government Digital Services (GDS) standards which ensured that it could be used by as many people as possible. This allowed people, for example, to use speech recognition software or use the website with a screen reader;
• The online system for the electronic questionnaire (eQ) went ‘live’ with a ‘soft launch’ on 23 February 2021 and ‘officially launched’ on Monday 1 March 2021. The system was designed to be accessed on a variety of technology such as laptops, mobile phones, tablets, personal computers, TVs etc., using a wide range of web browsing software;
• In total, 49% of online returns were completed on a mobile phone, 42% on a personal computer/laptop and 9% on a tablet computer;
• The online system offered the public the option to request that access codes be sent via text message to their mobile phone. This facilitated access to the online questionnaire and this process also supported the receipt of a confirmation e-mail. The system also provided online help with specific information available in up to 17 languages. In addition, there was dedicated help for people covering a wide range of issues, including students, vacant properties and holiday homes;
• The online system for data collection was available from Tuesday 23 February 2021 until Monday 24 May 2021 at 8pm (a period of 13 weeks).
Details of census returns during the operational period, including a breakdown of online/paper questionnaires and dates/times of completion can be found at Appendix F.
Further information on the digital services of the census and their design may be found on the Office for National Statistics website at Delivering the Census 2021 digital service.
6.4. Field operations
A final element in collection was a targeted ‘push’ on the doorstep of non-responders. This required the hiring of a team of almost 1,900 field staff (one enumerator for each of the 1,676 enumeration districts (EDs) plus managers). The main purpose was to visit properties for which no census questionnaire had been returned and, if possible, contact the householder and remind them of their legal obligation.
Field staff were managed by the field operations team within Census Office. To create the field team a recruitment campaign was launched in mid-2020 and staff recruited at three grades, 12 Census Area Managers (CAMs), 174 Census Team Co-ordinators (CTCs) and 1,676 Enumerators. Pressure on the timetable, largely due to the pandemic, resulted in only 1,530 enumerators taking up employment. This shortfall in numbers was covered by some enumerators taking on an additional enumeration district.
All field staff were provided with the necessary training and equipment. This included a smartphone, which enabled enumerators to manage their workload, as well as acting as both a communication and safety device. Enumerators accessed their daily workload through an application developed by TotalMobile, a local company. This application provided a list of non-responding addresses to ‘follow-up’.
6.4.1. Follow-up
Following up with non-responding households was important in increasing the return rate. A strategic approach was adopted. For example, in student areas ‘student specific’ postcards were delivered by enumerators during the ‘soft’ follow-up period (see below).
While census day was 21 March 2021, enumerators only started the ‘soft’ follow-up phase by visiting non-responding addresses from 26 March 2021. During the ‘soft’ follow-up enumerators assessed non-responding properties and, where necessary, delivered a targeted postcard indicating that no response had been received. Due to COVID-19 restrictions, there was no direct engagement with householders during this ‘soft’ follow-up phase.
Given the Easter holidays and the desire to allow the first posted reminder letters to have an impact, a pause in field operations ran from 2 – 7 April, with the regular follow-up period starting on 8 April. Details of follow-up phases are shown below:
Table 2: Census 2021 follow-up phases
| Phase | Date from | Date to | Objective |
|---|---|---|---|
| 1 | 26-Mar | 01-Apr | Soft follow-up |
| 1 (cont.) | 08-Apr | 18-Apr | Regular follow-up |
| 2 | 19-Apr | 25-Apr | Regular follow-up |
| 3 | 26-Apr | 02-May | Regular follow-up |
| 4 | 03-May | 09-May | Regular follow-up |
The regular follow-up period, during which enumerators ‘knocked on doors’ in an attempt to make contact with the householder, ran from 8 April until 9 May. In total 375,286 visits were carried out by enumerators during the follow-up period, full details of visits and return rates can be found at Appendix G.
6.5. Operational period
To run Census 2021 required consultation, legislation and the development of a host of operational plans. However, the main operational data collection period was short, running for 13 weeks from 23 February to 24 May 2021. It can be defined broadly as the ‘data collection’ phase either side of census day. The key milestones are shown in the diagram below:
The main systems including the census digital infrastructure (for example, website, online questionnaire (eQ) and online help) went live from 23 February. The online questionnaire closed down on 24 May, while the non-digital data collection process (paper questionnaires), the contact centre and online help website all remained operational until 8 July. An outline of the main timeline is shown below:
Monday 22 February Postcards issued & advertising phase 1 commences
All households received an initial postcard, advising that the census was coming. The public advertising campaign began on TV, radio and social media.
Tuesday 23 February eQ, website and online help goes live
Much of the census data collection IT infrastructure went live, including the online questionnaire, website and online help. The website had the facility to request an access code and the first online questionnaire was receipted on this date.
Monday 1 March Contact centre opens
With the landing of the first questionnaires this week, the contact centre opened on Monday 1 March, and the first calls were received on this date. As householders received their letters/questionnaires, there was a natural spike in calls to the contact centre, with numbers rising rapidly to more than 10,000 calls on Thursday 4 March.
1-2 March Initial paper questionnaires delivery
Paper questionnaires for the 168,000 addresses listed to receive a paper form were put into the postal system in two batches on 26 and 27 February, to ensure that they would start to land with addresses on 1 and 2 March.
3-5 March Initial contact letters delivery
Initial contact letters for the 675,000 addresses listed as ‘online first’ were put into the postal system in three batches between 1 and 3 March. The letters contained a unique access code that was needed to complete the census. Householders also had the option to request a paper questionnaire online or from the contact centre. By 3 March some 21,000 households had already submitted a census return.
Saturday 6 March Advertising phase 2 commences
Advertising now became more focussed, with the message that census day was fast approaching and encouraging householders to complete their census return.
Saturday 13 March Enumerators appointment & briefing
With enumerator managers already in post, the remainder of the temporary field staff started employment. Although the official start date for enumerators was 6 March, online appointment & briefing sessions were held on 13 March.
Monday 15 March Pre-census day postcards issued
Postcards were issued to all addresses, reminding householders that census day was nearly here, and encouraging them to complete. The advertising message was increased and numerous radio/TV interviews held. Return levels had already risen to 40% by Monday 15 March.
Friday 19 March Advertising phase 3 commences
With census day fast approaching, the advertising message is stepped up further, encouraging householders to complete their census return.
Sunday 21 March CENSUS DAY
The overall number of receipted household returns at the end of census day stood at 601,000, which represented a receipted return rate of 71%. Paper returns in the postal system were not fully receipted until 23 March.
Monday 22 March Post-census day postcards issued
Postcards were issued by way of a thank you, or a gentle reminder to all addresses to complete their census questionnaire if they had not already done so.
Monday 22 March Advertising phase 4 commences
Advertising campaign was now at its height, making use of the full range of media (TV, radio, outdoor, website and social media etc.).
Friday 26 March ‘Soft’ follow-up phase begins
Enumerators began the first phase of follow-up with households that had not yet responded. This was termed a ‘soft’ follow-up whereby postcards were hand delivered to addresses, but no direct contact made with the householder.
Wednesday 31 March Reminder 1 to non-responding households
Targeted reminder letters landed with non-responding addresses, with a reminder to complete their census form. This resulted in further calls to the contact centre, with over 12,000 calls received on 31 March. The return rate had risen to 81%.
Thursday 8 April Field regular follow-up commences
Enumerators began the regular follow-up phase, making contact with householders who had not yet responded, and encouraging them to make their return. The overall return rate continued to rise, reaching 89% by 11 April.
Monday 12 April Advertising phase 5 commences
The advertising message has become firmer, with an emphasis on reminding the public of their obligation to complete their census form.
Monday 19 April Reminder 2 to non-responding households
Reminder letters with a ‘firmer’ message were issued to non-responding households. This reminder also included with the letter a paper questionnaire, giving householders who may have been hesitant to complete online, the option to complete on paper.
Sunday 9 May Field staff follow-up phase ends
Enumerators had been following up with non-responding households on a regular basis from 8 April – this work closed on Sunday 9 May.
Monday 10 May Reminder 3 (final) to non-responding households
Final reminder letter issued to all non-responding households encouraging them to complete their census return. There was a noticeable increase in phone calls to the contact centre following the issue of each reminder letter.
Monday 24 May Online data collection system closes
The return rate at the end of the main operational period stood at 96.8% (80.6% online). This would creep up further, as more paper questionnaires were received.
Thursday 8 July All main data collection systems close
The option to submit a paper questionnaire via the main systems providers remained open until 8 July. The call centre closed on this date, effectively marking the end of the supplier led data collection period.
The option for householders to submit paper questionnaires via the main system providers remained open until 8 July. This resulted in a final return rate of 97.2%, of which 80.6% was online.
7. Conclusion
The Census 2021 data collection operation was carried out against a backdrop of a worldwide pandemic, in circumstances that were both challenging and unprecedented. Working closely with its various partners, Census Office had to be flexible and to adapt, often at short notice, to the ever-changing environment.
Despite the significant challenges presented by COVID-19, the census can be regarded, from an operational viewpoint at least, as a huge success with an overall return rate of 97.2%. This compares very favourably to 2011, when the return rate was 93.6%.
In line with the NICS Digital Transformation programme, the focus of the Census 2021 data collection operation was on promoting a ‘digital first’ approach, and it was therefore encouraging to note 80.6% of addresses completed online and 19.4% on paper1. While this was not unexpected, given the move in recent years towards accessing government services online (for example, passports, driving licences etc.), it is believed this figure was also a reflection of a system that the public found easy to access and straightforward to use.
The next phase of the Census is the data processing element. This is currently being undertaken and Census Office will report on this element when complete. An Outputs Prospectus has also just been published in January 2022 which gives a detailed timeline of the results planned in the final outputs phase of Census 2021.
Census Office
January 2022
Appendix A: Contracts and suppliers
The majority of contracts were procured jointly with ONS. These are listed below:
• Census field operational devices contract was awarded to XMA Ltd;
• Census field force logistics and replenishment contract was awarded to Granby Marketing Services Ltd;
• Census paper questionnaire return service contract was awarded to Royal Mail;
• Census print and post contract was awarded to HH Associates;
• Census questionnaire management contract was awarded to Leidos Innovations UK;
• Census public contact centre contract was awarded to Serco;
• Census fieldwork management tool contract was awarded to TotalMobile;
• Contract for translation of paper questionnaire into 15 languages was awarded to K International;
• British Sign Language (BSL) and Irish Sign Language (ISL) video production was awarded to the Royal Association for Deaf people (RAD);
• Contract for production of census questionnaire translation in BSL and ISL awarded to Signed Up;
• Production of Easy Read leaflet contract awarded to Easy Read UK.
In line with government procurement guidelines a number of other local contracts were also let:
• Marketing and advertising contract was awarded to Genesis Advertising Ltd;
• Census in schools – Contract awarded to CCEA for the production of 12 lesson plans for primary schools.
Field staff recruitment and payroll services were provided by HR Connect (NI Civil Service contracted HR provider).
Appendix B: Definitions of census terminology
• Operational period – the weeks either side of census day, running from 23 February 2021 (when advertising had just started and many of the census online systems went live) to 24 May 2021 when the online questionnaire closed. The contact centre, website and option to complete and return a paper questionnaire via suppliers remained operational until 8 July);
• Data Collection Services – all the systems and processes associated with the completion and collection of census data (for example, online help, contact centre, return management, print and post of forms etc.);
• Field Operations – all elements that relate to work carried out on the ground by field staff (for example, recruitment, training, logistics, devices, follow-up with households etc.);
• Wave of Contact – the timeline and nature of communications/contacts made with the householder;
• Follow-up – period after census day, during which follow-up (field and reminder letters) with non-responding householders was carried out;
• Response management – the digital infrastructure that supports all aspects of online and paper questionnaire completion;
• Electronic questionnaire (commonly referred to as eQ) – the means to complete the census online;
• Communal establishment – term for any type of managed accommodation, such as prisons, military bases, university halls of residence, care homes, hospitals and hotels.
Appendix C: Social media and website
Between 23 February and 24 May 2021, 709,700 user sessions and 54.4 million page views were recorded on the Census NI website. These were only those sessions, and hence page views, where users agreed to select Google Analytics website usage cookies. It is estimated that approximately 65% of the overall number of user sessions accepted cookies, so the total sessions and page views for the Census 2021 website (in Northern Ireland) are likely to have been much higher, potentially around 1 million and 80 million respectively. The total sessions and page views included all aspects of the website from online help to the online questionnaire (eQ).
Appendix D: Samples of postcards and contact letters
Appendix E: Number of daily calls logged by contact centre up to 24 May 2021
Figure A: Number of call centre telephone calls by day
Appendix F: Number of census returns by day
Figure B: Number of census household returns by day
Online/paper returns (cumulative)
Figure C: Cumulative number of census household returns by day and return type
User session by time of day
Figure D: Percentage of user (sessions) by time of day
Appendix G: Cumulative number of visits and return rates by follow-up phase
Figure E: Census return rates by phase
It should be noted that these figures represent return rates during the field follow-up period, reaching 96.4% at the end of phase 4. This figure continued to rise in the subsequent weeks, reaching a final return rate of 97.2% by 8 July when all systems closed.