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Census2001 Output

Samples of Anonymised Records (SARs)

Contents

	Introduction - SARs
	SARs Products 1: Individual Licensed SAR 2: Individual CAMS 3: Special Licence Household SAR 4: Household CAMS 5: Small Area Microdata (SAM) Confidentiality

Introduction – SARs

NISRA has been working in collaboration with the Office of National Statistics (ONS), The General Registry Office of Scotland (GROS), The Cathie Marsh Centre for Census and Survey Research (CCSR) and the Economic and Social Research Council (ESRC) who funded the work to make available Samples of Anonymised Records (SARs) from the 2001 Census for research purposes.  These SARs consist of extracts from Census records which are designed to enable researchers to carry out detailed analyses using 2001 Census data for individuals and households.  

SARs were made available for the first time in the UK following the 1991 Census. They are a UK product that differs from any other data previously produced from the UK Censuses offering samples of individual and household records, which have been adapted in order to conceal the identity and preserve the confidentiality of respondents.  This is achieved by removing any identifying characteristics or information, such as the respondents name and exact address, and by restricting the level of detail made available. Back to Contents  

SARs Products

There are five main SARs products available from the 2001 Census as detailed below.  

1:  Individual Licensed SAR

The first of these samples, the Individual licensed SAR, contains a 3 per cent sample that relates to some 1.84 million records of responses from the 2001 Census from across the UK. This data have been completely anonymised so that no individuals from the Census can be identified. Some 51,000 of the records relate specifically to Northern Ireland and these can be identified through the “region” variable.

The following information is given for each individual:

	main demographic (e.g. sex/age/marital status), health and socio-economic variables;
	derived variables, e.g. social class; household information (e.g. tenure and availability of amenities/car);
	information about the sex, economic position and social class of the individual's family head;
	limited information about other members of the individual's household (e.g. the number of pensioners); and
	Area identification (eg. GOR level in England and country level for Northern Ireland, Scotland and Wales).

The Individual Licensed SAR is now available from CCSR (a charge may apply).  For more information or to register for access and further information on guidance and training, please click HERE.

Click Here for the Individual Licensed SAR Codebook

A more detailed version of the individual SAR - the Controlled Access Microdata Sample (CAMS) - is available in house at ONS.  Please see below for more details.

  Back to Contents  

2:  Individual CAMS

The Individual Controlled Access Microdata Sample (CAMS) is a more detailed version of the Individual Licensed SAR available via a secure setting known as a Microdata Laboratory.  The CAMS files contain geography at Parliamentary Constituency level for Northern Ireland (Local Authority for England , Wales and Scotland ), full occupational detail (unit SOC), industry and more detail on many other variables. In total the file contains about 200 variables and provides a considerable amount of detail. 

Approved researchers will only be able to access the data in the Microdata Laboratory by arrangement with the ONS at their Titchfield, London , Newport and Southport Offices.

Researchers must submit an application to the Census Research Access Board (CRAB), justifying their need for access to the data.  CRAB will review and approve/reject the application, and any analysis carried out on the data will be checked for disclosiveness before being released from the laboratory. 

The Individual CAMS is now available at ONS.  For more information or to register for access and further information on guidance and training, please click HERE.

Click Here for the Individual Licence CAMS codebook

   Back to Contents

3:  Special Licence Household SAR

The Special Licence Household SAR consists of a 1 per cent sample of household and individual records from households in England and Wales only.  It contains information for some 225,436 households and 525,715 individuals, however, individual records are available only for households with 11 or fewer residents.

ONS developed a Special Licence to allow them to make available slightly more detailed microdata than would be possible with a standard End User Licence.

The Special Licence Household SAR is now available from CCSR (a charge may apply).  For more information or to register for access and further information on guidance and training, please click HERE.

Click Here for the Special Licence Household SAR Codebook

A more detailed version of the Special Licence Household SAR - the Controlled Access Microdata Sample (CAMS) - is available in house at ONS and contains data for Northern Ireland and Scotland , as well as England and Wales .

Back to Contents

4: Household CAMS

The Household Controlled Access Microdata Sample (CAMS) is a more detailed version of the Special Licence Household SAR.  The CAMS file contains Geography at Parliamentary Constituency level for Northern Ireland (Local Authority for England , Wales and Scotland ).  As with the Individual CAMS data, approved researchers will only be able to access the Household CAMS data by arrangement with the Office for National Statistics at their Titchfield, Southport, Newport and London Offices.  The same application procedures apply as those detailed for the Individual CAMS as above. 

The Household CAMS is now available at ONS.  For more information or to register for access and further information on guidance and training, please click HERE.

Click Here for the Household CAM codebook

5:  Small Area Microdata (SAM)

A further 5% sample of Small Area Microdata (SAM) contains 2.96 million individual records from all countries in the UK .  Each individual record includes variables of the Parliamentary Constituency level within Northern Ireland (Local Authority within England and Wales and Council Areas for Scotland ).  The variables included are similar to those in the individual SAR, although the amount of individual detail in the SAM is less than in the Individual SAR because of the greater geographical detail in the SAM.  Unlike the Individual SAR, there is not a more detailed version of the SAM available under Controlled Access.  

The SAM is now available from CCSR (a charge may apply). For more information or to register for access and further information on guidance and training, please click HERE.

Click Here to view the SAM file codebook

Further information on SARS is available from the ONS website (www.statistics.gov.uk/census2001/sar_update.asp)

Confidentiality 

Protecting confidentiality is becoming more and more difficult with each Census due to the availability of alternative data sources.  With a greater amount of accessible information being made publicly available more information can be matched statistically with the Census.

Each Northern Ireland Census form stated that: 

“The information you provide is protected by law and treated in strict confidence.  The information is only used for statistical purposes, and anyone using or disclosing Census information improperly will be liable to prosecution.  Census forms will be held securely under the terms of the Public Records Act (Northern Ireland) 1923.”  

The Census offices also have a clear, well published, goal for protecting the confidentiality of individual information:

...In releasing statistics from the Census, all possible steps will be taken to prevent the inadvertent disclosure of information about identifiable individuals and households.

In addition, the Registrars General have a legal obligation not to reveal information connected in confidence in the Census about individual people or households, and have given public assurances about what this means in practice.

Therefore there is a strong emphasis, as well as a legal obligation, to ensure that the SARs data does not pose a risk of disclosure.  This has led to many analyses being carried out on the data before any of the SARs products are made available to the public. Each variable will be analysed for disclosure risk and, from the assessed potential risk, will be collapsed accordingly. The 2001 SAR will not be as detailed as the 1991 version due to the outcome of these analyses. 

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Contents of 2001 SARs