Introduction
This page brings together all the key reference materials from Census 2021 in Northern Ireland. Whether you're analysing data, comparing trends, or exploring methodology, you'll find everything you need here.
General information
Census 2021 questionnaires
Sample copies of the Census 2021 questionnaires are available to download.
Census 2021 frequently asked questions
A selection of the most frequently asked questions (FAQs) to help you find out more about Census 2021.
Census 2021 operational report
This document is a factual account of how the census was conducted and sets out a record of key elements associated with the operational delivery.
Data tools
Census 2021 table lookup
Search all published tables by topic. Updated regularly as new data is released.
Methodology and quality
Census 2021 statement about data quality
This document aims to assist users by providing information on two aspects of quality: the response rate and the item response rate.
Census 2021 population and household estimates for Northern Ireland - quality assurance report
This document provides an overview of the quality assurance work that has been undertaken by NISRA, to ensure that the Northern Ireland census population estimates are of high-quality, fit-for-purpose, and meet the needs of users.
Census Quality Survey (CQS)
This paper describes the methodology and findings of the CQS in 2021. It outlines the extent to which the responses provided in the CQS, to both the household and individual questions, agreed with those captured in the census.
Census 2021 methodology overview
This document provides background information on the processes that underpin Census 2021 outputs. By detailing these processes, users will understand the underlying quality of the Census 2021 outputs.
Census 2021 data processing overview
This document outlines the main stages of data processing for Census 2021.
Census 2021 edit and imputation processing report
This document explains how missing or inconsistent responses in Census 2021 were addressed to ensure complete and consistent data. By detailing the edit and imputation process – including the use of logical rules and statistical techniques – users can better understand the accuracy and integrity of the final census outputs.
Special topics
Census 2021 guidance note on use of religion question outputs
Census 2021 contained two religion questions, the first on ‘current religion’ and a follow-up question on ‘religion of upbringing’. This guidance note describes the background to the inclusion of religion questions in the census, the processing of census religion data, and the subsequent reporting of census religion results.
Census 2021 coverage information paper
This paper describes the approaches taken to adjust for undercoverage and overcoverage in Census 2021, and the quality assurance undertaken to validate the robustness of the data.
Census 2021 addressing information paper
This paper details the stages of development and creation of the Census Address Register (CAR), including its maintenance and continued development during the operational phase of Census 2021, and its finalisation during data processing.
Census 2021 student information paper
This paper outlines the initiatives undertaken in Census 2021, both in the enumeration and data processing phases, to ensure that students were counted accurately.
Impact of COVID-19 on Census 2021 in Northern Ireland
More information on the potential impacts of the coronavirus (COVID-19) pandemic on the data collection and output from Census 2021.
Comparability and definitions
2021-2011 Census in Northern Ireland questionnaire comparability report
This report helps users look at differences in the census questionnaires across the 10-year period, between 2011 and 2021.
Census 2021 outputs definitions
This document provides definitions for terms used in the preparation and publication of statistics from the 2021 Census in Northern Ireland.
Census 2021 variables index
Information collected through the census questions becomes data, which is output through variables. This document details each variable and contains information such as the variable definition and categories.