Initial design

Information on the initial design of the 2021 Census in Northern Ireland.

This section sets out initial thinking for the design of the 2021 Census in Northern Ireland.

The design draws on experiences from the 2011 Census, international best practice, consideration of technological and societal changes. These will all shape the scope, main objectives and design of the 2021 Census as well as help us consider what changes are required since the last census.

Further information on designing the questionnaire, ensuring inclusion, supporting information, stakeholder engagement, plans for publicising the census and more can be found in the 'Key elements of the 2021 Census design' section.


The 2011 Census in Northern Ireland was judged a success by NISRA. Given this, the key strategic objectives for 2011 have been retained for 2021. Consequently, the key high level strategic objectives for 2021 are:

  • to provide high quality, value-for-money and fit-for purpose statistics that meet user needs
  • to maximise overall response rates and minimise differences in response rates in specific areas and among particular population sub-groups
  • to protect, and be seen to protect, confidential personal census information
  • to secure public and user confidence in the final results and deliver them in a timely manner

Building on these strategic objectives, and reflecting the scope of the project, the value of the census will also be articulated through its use and re-use. A further two high level objectives have been agreed:

  • to encourage wider use and exploration of census results to facilitate greater benefits from census outputs
  • when developing tools for the census to ensure they are designed with the potential option of re-use by other areas of NISRA or for other purposes

Additionally, one further main operational objective has been identified as follows:

  • to deliver a high quality 2021 online census data collection operation

Informing the high-level design

The initial high-level design for a 2021 Census is informed by:

  • lessons learned and successes, where appropriate, from the 2011 Census
  • developments and lessons learned in international census taking
  • requirements from the user community about the types, quality, frequency and detail of outputs required
  • changes in technology, in particular the opportunities offered by the internet, and changes in the propensity for the public to interact with government, enabling a move away from a traditional paper-based census
  • improvements in administrative data sources giving potential for increased use in the production of statistics
  • the continued and ongoing need to make the most effective use of public money
  • impact assessments

The design will evolve as the project develops and the different design elements are first tested independently and then tested together.

Design principles

We have identified design principles that will guide the development and finalisation of the design for 2021.

These include:

  • utilising the elements of the 2011 Census that worked well and are still relevant
  • embracing new technologies and methods wherever possible
  • designing the operational and statistical processes for online first
  • seeking to minimise the respondent burden on the public
  • protecting confidential personal data
  • informing the public about how we will protect confidential personal data
  • testing the census design iteratively to assure us and stakeholders of the underlying system, processes and security of the overall design
  • attempting to get a response from every person and household in Northern Ireland
  • developing the operation and statistical methods employed to deliver the highest quality for the population estimates by age and sex at the local government district level
  • maximising appropriate use of administrative data in all areas of the operation
  • estimating and adjust the results to account for over and under-enumeration as in the 2001 and 2011 Censuses
  • making the first results available more quickly than results from the 2011 Census and also seek to complete the full suite of outputs (still to be defined) more quickly than 2011

Main areas of change between the 2011 and the 2021 Census

The '2011 Census General Report' details how we undertook the 2011 Census. The 2021 Census in Northern Ireland will build upon our experience in delivering that census, but we are already clear there will be some significant changes for 2021.

The primary changes for the 2021 Census in Northern Ireland are:

  • primarily online
  • initial post out of contact letter including Internet Access Codes and very limited hand-delivery of materials by census staff
  • making use of administrative data to support the collection and processing of census data
  • targeted follow-up of non-responding households
  • more flexible means of dissemination

Related statistics

Key elements of the 2021 Census design

This section highlights the key elements of the design which includes initial thinking on the 2021 questionnaire, how we are planning on ensuring inclusion and supporting respondents, engaging with our stakeholders and plans for publicising the census.

Read more