ONS has been working in collaboration with 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.The SARs contain individuals' responses from the 2001 Census. Some variable categories have been combined and some perturbation applied to the data to protect the confidentiality of individuals.
There are 3 licensed SARs datasets and within each, 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; accommodation (e.g. tenure and availability of amenities/car);
information about the sex, economic position and social class of the individual's family head; and
for the Individual Licensed SAR and SAM, limited information about other members of the individual's household.
These datasets are suitable for use with many common statistical software packages such as SPSS (Statistical Package for the Social Sciences) and STATA (Statistical Software for Professionals).
Individual Licensed SAR
This dataset contains a 3 percent sample, which relates to some 1.76 million records in the UK with a geographic reference showing Scotland, Northern Ireland or the Government Office Region of England. The Individual Licensed SAR is available from CCSR (although a charge may apply). To register for access and for further information on guidance and training, please go to www.ccsr.ac.uk/sars/ and follow the link for access and registration.
Special License Household SAR
The Special Licence Household SAR contains a 1 percent hierarchical sample of households and individuals in those households. It has around 245,000 household records and covers England and Wales only. The information above is given for each individual in households of size up to and including 11 persons.
It was originally planned to make the Household SAR available through CCSR similarly to the Individual Licensed SAR. In Spring/Summer of 2005 ONS considered users' needs and assessed various coding options that would provide sufficient confidentiality protection. However, the level of recoding necessary for disclosure control resulted in loss of detail that rendered the data of little use to researchers. It was important that customer needs were balanced with confidentiality of information but it became clear that a different approach would be needed to allow access to a useful household file
During this time, ONS was reviewing its policy on microdata access generally and approved access to more detailed datasets for social surveys which allowed a combination of i) statistical disclosure methods with ii) legally binding agreements to protect data confidentiality. This approval was extended to the household SAR so that ONS could provide a more useful file that contained enough detail for researchers needs whilst still maintaining confidentiality. In addition to the Special Licence, statistical disclosure control measures in the form of recoding and a small amount of perturbation have been applied to the file.
The Special Licence Household SAR is available from the UK Data Archive. If you are interested in applying for access to the data file, follow the link for requesting a download of the data on the Special Licence and complete the Special Licence. Your Special Licence application will then be assessed by both the UKDA and ONS. You will be notified of the outcome as soon as possible. Users should also note the 'Guide to Good practice: microdata handling and security' contained in the link above and agree to abide by its requirements
When applying for access to the Special Licence Household SAR users must already be registered with the Economic and Social Data Service (ESDS) or the Census Registration System (CRS) and have an Athens ID number. Users can apply for ESDS registration via the UK Data Archive website.
Small Area Microdata
The Small Area Microdata (SAM) is a 5 percent sample containing 2.9 million individual records in the UK with Local Authority level geography identified for England, Wales and Scotland; and Parliamentary Constituencies for Northern Ireland. The variables included are similar to the main information above, though broader banding has been used to protect confidentiality at the lower geography. The SAM is expected to become available from CCSR at the end of November 2005. To register for access and for further information on guidance and training, please go to www.ccsr.ac.uk/sars/ and follow the link for access and registration.
Controlled Access Microdata Samples (CAMS)
If you require access to a more detailed SARs dataset or would like access to the Household SAR for Scotland and Northern Ireland then see the Controlled Access Microdata Samples (CAMS) where access is available, subject to approval through the Census Research Access Board, at the following ONS sites: London, Newport, Titchfield and Southport.
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