Title

Usual resident population by local authority, sex and five-year age groups

Last update

December 2022 December 2022

Publishing organisation

Welsh Government

Source 1

2021 Census, Office for National statistics

Designation

National Statistics

Geographical coverage

Local authorities

Languages covered

English and Welsh

Data licensing

You may use and re-use this data free of charge in any format or medium, under the terms of the Open Government License - see http://www.nationalarchives.gov.uk/doc/open-government-licence

General description

The Office for National Statistics (ONS) published the first results from Census 2021 for Wales and England on 28 June 2022. These first results included rounded population and household estimates for local authorities in Wales, by sex and five-year age groups. Unrounded population estimates by sex and single year of age were released on 2 November 2022.

This StatsWales table is based on Census table TS009 – Unrounded population estimates by sex and single year of age. For Census 2021, the ONS made changes to the data (called statistical disclosure control) so that it is not possible to identify individuals. These changes included:
• Swapped records (targeted record swapping), for example, if a household was likely to be identified in datasets because it has unusual characteristics, they swapped the record with a similar one from a nearby small area. Very unusual households could be swapped with one in a nearby local authority.
• Added small changes to some counts (cell key perturbation), for example, change a count of four to a three or a five. This might make small differences between tables depending on how the data are broken down when perturbation is applied.
This causes small changes to cells but does not fundamentally impact the meaning of the data. Where tables are made in different ways, the changes applied will be different, leading to differences between totals and tables not ‘adding-up’ to their totals. To minimise this, the ONS recommends where possible using totals from tables with fewer cells, at higher geographies. For example, if you wanted population by age you should use data from TS007 and if you wanted population by sex you should use data from TS008.

More information about the processes used in statistical disclosure control will be provided in future publications.

A usual resident of Wales is anyone who was living or staying in Wales for 12 months or
more on Census Day, 21 March 2021, or who had a permanent address in Wales and was staying outside Wales for less than 12 months.

Data collection and calculation

See weblinks

Frequency of publication

No longer updated

Data reference periods

21 March 2021

Users, uses and context

The data presented here are used by central government departments and local authorities for a range of purposes including for resource allocation, planning and monitoring of services, and as denominators for the calculation of various rates and indicators.

Rounding applied

To note the sums of local authorities may not add up the Wales figures due to the statistical disclosure methods applied to the data as described in the general description. Figures across different tables may also not match exactly due to statistical disclosure control methods applied to the data.

Statistical quality

Further information on the statistical disclosure controls (including perturbation) that have been applied to the data can be found here:
https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/methodologies/qualityandmethodologyinformationqmiforcensus2021#methods-used-to-produce-the-data

Weblinks

https://gov.wales/population-and-household-estimates-wales-census-2021
https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/methodologies/qualityandmethodologyinformationqmiforcensus2021#methods-used-to-produce-the-data

https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/bulletins/populationandhouseholdestimateswales/census2021

Keywords

2021 Census; population

Name

POPU2101