Census aggregate data guide

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"Data about individuals and households within areas"

What are census aggregate data?

The aggregate data produced as outputs from censuses in the United Kingdom provide information on a wide range of demographic and socio-economic characteristics of the population. They are predominantly a collection of aggregated, or summary, counts of the numbers of people, families or households resident in specific geographical areas or ‘zones’ possessing particular characteristics, or combinations of characteristics, drawn from the themes of population, people and places, families, ethnicity and religion, health, work, and housing.

An example of the kind of information available from the aggregate data might be the numbers of people who are aged over 50 and are unemployed (a combination of characteristics) within each of the wards in the district of Greater Manchester (a set of geographical zones). The characteristics could include a wide range of information on demographic and socio-economic themes that is gathered as part of the census process.

The aggregate data are the most commonly and widely used component of the outputs from UK censuses. They are derived from analysis of the information provided in census returns. The 2001 Census aggregate data are based on analysis of a full sample of all returned forms, with adjustment in the outputs for people and households who may have been missed out and not been recorded on a form, or alternatively, may have been counted more than once by being recorded on more than one form.

The information that can be obtained from the aggregate data is presented as a series of over 1000 pre-defined univariate and multivariate tabulations. An illustration of what this means is given by means of the example below.

Aggregate data for Zoneworld

‘Zoneworld’ is an imaginary set of four zones inhabited by a population of 50 individuals whose basic age and gender characteristics are illustrated below:

The information that it is possible to obtain from the census about the age and sex of the residents in the different zones can be represented in the following cross-tabulation of simple classifications of age and gender.

Age/Sex Male Female
Over 16 count_1 count_2
Under 16 count_3 count_4

An identifier or code, count_1, for example, is used to show that information about the number of males who are over 16 years of age is available for each of the zones of Zoneworld. Thus, we see from the cross-tabulation below that in Zone A there are 3 male individuals aged over 16 and 3 females aged over 16, for example:

  count_1 count_2 count_3 count_4
Zone A 3 4 2 3
Zone B 4 3 1 3
Zone C 6 6 3 4
Zone D 4 3 0 0

Aggregate data are available for the full range of geographies employed within the census, from the smallest (output areas with an average of 150 persons in England and Wales) to the nation as a whole.

For further information about the geographies used in the output of census aggregate data, see the section on census geography in the Office for National Statistics’ Beginner’s Guide to UK Geography.

What can census aggregate data tell us?

Census aggregate data provide the most complete source of information about the demographic and socio-economic characteristics of the UK population that is available. They provide a wide range of comparable information at a range of geographical levels across the entire UK and so can be used to describe and compare population characteristics in different locations across the UK.

The primary purpose of censuses in the UK is to provide central and local government with the information required for them to target resources and services effectively to meet the anticipated needs of the population. Census aggregate data are also widely used across the academic sector for research and teaching and across the private sector for marketing and site location.

Census aggregate data can be used by themselves but are also often combined with information from other sources to provide background or context. They have also been used to create derived measures, such as deprivation scores or area classifications.

Obtaining the data

The UK Data Service Census Support, provides web-based interfaces that enable users to access and extract data from the aggregate statistics outputs from the 1971, 1981, 1991, 2001 and 2011 Censuses, together with a range of associated datasets and services.

InFuse contains 2011 and 2001 Census aggregate data, but we will be adding more 2011 data as and when we process it. InFuse is an intuitive interface that allows you to select data by topics rather than by table.

Casweb is our older interface, which contains 1971, 1981, 1991 and 2001 Census aggregate data as well as 1991 and 2001 Census boundary data. We are no longer updating Casweb and are concentrating our resource into developing InFuse.

Anyone can access InFuse and Casweb.

How to access census aggregate data in InFuse

View our video tutorial on using our open access census support tool, InFuse.

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