Civometry calculation
Share of usual residents by ethnic group, Census 2021
Usual residents in each broad ethnic group (ONS Census 2021, TS021) as a share of all usual residents (ONS Census 2021).
How it is calculated
- Numerator
- Census 2021 ethnic group (five broad groups) · split by Ethnic group
- Denominator
- Census 2021 usual residents
- Formula
- numerator ÷ denominator × 100, expressed as a percentage
- Result is measured in
- % of residents
- Which population is used
- same period
- Suppressed when
- the numerator is below 10 or the population below 1,000, so small numbers are not published as rates
How the categories are matched
The two sources do not use the same category names. Every numerator category is mapped to exactly one denominator category, and nothing is merged or dropped silently.
| In the numerator | Matched to |
|---|---|
| Asian, Asian British or Asian Welsh | Asian, Asian British or Asian Welsh |
| Black, Black British, Black Welsh, Caribbean or African | Black, Black British, Black Welsh, Caribbean or African |
| Mixed or Multiple ethnic groups | Mixed or Multiple ethnic groups |
| White | White |
| Other ethnic group | Other ethnic group |
What it covers
Every geography the census stream ingests (England and Wales, local authorities and smaller areas), Census day 21 March 2021.
What this calculation cannot tell you
- Ethnic group is self-reported on the census form by the person or the householder; the census does not ask about nationality or country of birth in this question.
- Small areas are subject to ONS disclosure control, so components may not sum exactly to the published total.
Check it yourself
Every calculated value stores the numerator, the denominator and the identifiers of the two official observations it came from. Open the numerator and denominator above, take the figures for the same period and category, and apply the formula. If you get a different answer, tell us where it diverges.