Reference materials

These materials are designed to help users make the most of census data.

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 to help you find out more about Census 2021. Last updated on 22 September 2022.

Census 2021 table lookups

Use the Census 2021 table lookups to search all Census 2021 tables by topic. This document will be updated as more data are released.

Census 2021 statement about data quality

The Census 2021 statement about data quality aims to assist users by providing information on two aspects of quality: the response rate and the item response rate.

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 outputs definitions

This document provides Census 2021 outputs definitions for terms used in the preparation and publication of statistics from the 2021 Census in Northern Ireland. Last updated on 22 September 2022.

Census 2021 variables index

Information collected through the census questions becomes data, which is output through variables. The Census 2021 variables index details each variable and contains information such as the variable definition and categories.

Census 2021 methodology overview

The purpose of the Census 2021 methodology overview is to provide background information on the process that underpins Census 2021 outputs. Through detailing these processes, users will gain an understanding of the underlying quality of the Census 2021 outputs.

Census 2021 population and household estimates for Northern Ireland - quality assurance report

The purpose of the Census 2021 population and household estimates for Northern Ireland - quality assurance report is to provide an overview of the quality assurance work that has been undertaken by NISRA, in order to ensure that the Northern Ireland census population estimates are of high quality, fit for purpose, and meet the needs of users.

Census 2021 operational report

On 31 January 2022, NISRA published the Census 2021 operational report (PDF 943KB). 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.

Census 2021 data processing overview

NISRA has published an overview of the data processing methods for the 2021 Census (PDF 65KB). This document outlines the main stages of data processing for Census 2021.