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ONS 2021 Census (CENS)

Population Size

59,597,300

People

Years

2021 - 2021

Associated BioSamples

None/not available

Geographic coverage

United Kingdom

England

Lead time

Other

Summary

A census in the UK is a count of all people and households. This census in the UK was held on 21 March 2021.

Documentation

Every ten years since 1801 the nation has set aside one day for the census - a count of all people and households. It is the most complete source of information about the population that we have. The latest census was held on Sunday 21 March 2021.

Every effort is made to include everyone, and that is why the census is so important. It is the only survey which provides a detailed picture of the entire population, and is unique because it covers everyone at the same time and asks the same core questions everywhere. This makes it easy to compare different parts of the country.

The information the census provides allows central and local government, health authorities and many other organisations to target their resources more effectively and to plan housing, education, health and transport services for years to come.

In England and Wales, the census is planned and carried out by the Office for National Statistics. Elsewhere in the UK, responsibility lies with the National Records of Scotland and the Northern Ireland Statistics and Research Agency.

A usual resident is anyone who on Census Day, 21 March 2021 was in the UK and had stayed or intended to stay in the UK for a period of 12 months or more, or had a permanent UK address and was outside the UK and intended to be outside the UK for less than 12 months.

The ONS have three processes for checking and resolving duplicate responses so that the main census data should simply be one record for each person:

  1. The ONS resolve duplicates coming in for the same postcode using a process called Resolve Multiple Responses (RMR). For instance, if two people both fill in a form for their whole household, or someone from a household also submits an individual response unknown to the main submission. They have rules for checking they are duplicates, and rules for which to keep.

  2. The ONS also do an over coverage check on a sample basis for duplicates across the rest of the country, and then factor the findings into their coverage estimation calculations. This sampling focuses on the types of population which are more likely to be duplicated (people who have indicated they have a second residence on the census, students aged 18-25, armed forces personnel, children, adults enumerated at a communal establishment, etc.) but also samples from the remaining population.

  3. The ONS ask parents to fill in basic demographic information for any children who are away studying, and when they get to the question on their term-time address, if they answer that the term-time address is elsewhere, we then use that to filter those out-of-term students out of the main database. Then when that student does respond actually at their term-time address, they only include them there.

Note: variables RELAT06, RELAT11, RELAT16, RELAT21, RELAT26, GENDER_IDENTITY are not available in the data

Dataset type
Health and disease
Dataset sub-type
Not applicable
Dataset population size
59597300

Keywords

SAIL, Census, Population, Resident Population, ONS, NCS, National Core Study, COVID-19, Housing & Communities, World of Work, Inequality & Social Inclusion, RAP

Observations

Observed Node
Disambiguating Description
Measured Value
Measured Property
Observation Date

Persons

59597300

Count

21 Mar 2021

Provenance

Purpose of dataset collection
Administrative
Source of data extraction
Other
Collection source setting
Community, Home, Other
Image contrast
Not stated
Biological sample availability
None/not available

Structural Metadata

Details

Publishing frequency
Static
Version
14.0.0
Modified

08/10/2024

Distribution release date

27/06/2022

Citation Requirements
Office for National Statistics

Coverage

Start date

21/03/2021

End date

21/03/2021

Time lag
Other
Geographic coverage
United Kingdom, England, Wales
Maximum age range
120
Follow-up
Unknown

Accessibility

Language
en
Controlled vocabulary
LOCAL
Format
SQL database table

Data Access Request

Dataset pipeline status
Available
Time to dataset access
Other
Access request cost
Data provision is free from SAIL. Overall project costing depends on the number of people that require access to the SAIL Gateway, the activities that SAIL needs to complete (e.g. loading non-standard datasets), data refreshes, analytical work required, disclosure control process, and special case technological requirements.
Access method category
TRE/SDE
Access service description
The SAIL Databank is powered by the UK Secure e-Research Platform (UKSeRP). Following approval through safeguard processes, access to project-specific data within the secure environment is permitted using two-factor authentication.
Jurisdiction
GB-WLS
Data use limitation
Research-specific restrictions
Data use requirements
Project-specific restrictions
Data Controller
Office for National Statistics
Data Processor
SAIL Databank

Dataset Types: Health and disease


Collection Sources: Community, Home, Other