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Plans for Access to UKMicrodata from 2011 Census
Emma White
Office for National Statistics
24 May 2012
Overview
• Introduction• 2011 Census progress• Proposed products• Challenges• Microdata progress to date
Introduction
• UK Censuses held since 1851• Usually every ten years
• Samples of anonymised records (SARs) made available for the first time in 1991• Great Britain and Northern Ireland separately• Two files: individual, household
• 2001• Five files: individual SAR, small area microdata, special licence
household SAR, individual and household controlled access microdata samples
2011 Census progress
• Confident that target response rates will be met• 94 per cent nationally• At least 80 per cent in every local authority in England and
Wales• Fewer than 10 per cent of local authorities will be below a 90 per
cent response rate
• 2011 Census first release planned for July 2012• Population estimates by age and sex to local authority• Household estimates
• Web-based prospectus launched 29 March 2012
Six proposed products
File
1. Secure: Individual Controlled Access Microdata Sample (CAMS)
2. Secure: Household CAMS
3. Safeguarded: Individual Samples of Anonymised Records (SAR)
4. Safeguarded: Household SAR
5. Public Use: Individual SAR
6. Public Use: Individual Test Dataset
Access level 3Secure products
File Sample size Geography Licence Availability
Individual Controlled Access Microdata Sample (CAMS)
3% Local authority/ Northern Ireland constituencies
Approved researcher
Office for National Statistics (ONS) Virtual Microdata Laboratory (VML)
Household CAMS
3% As above As above As above
Access level 2Safeguarded products
File Sample size Geography Licence Availability
Individual Sample of Anonymised Records (SAR)
5% Local authority
End user licence
Special user agreement/ Download
Household SAR
1% Regional or national
As above As above
Access level 1Public use products
File Sample size Geography Licence Availability
Public Use Individual Sample of Anonymised Records
3% Regional or national
Open Government Licence
Download
Public Use Individual Test Dataset
As above As above As above As above
Challenges
• Consolidation of England and Wales, Scotland and Northern Ireland data• Geography• Differences in questionnaires, variables and classifications
• Level of detail and/ or geography to include in each environment
• Licensing and access arrangements
Progress to date
• Statistical disclosure control: targeted record swapping• Potential for increased sample sizes
• Microdata file specifications prepared and under review• Single UK database agreed across the four countries,
planning underway• Microdata planned for release from Autumn 2013• Historical microdata under consideration
• 1961, 1966, 1971, 1981
Dr Emma White
Head of 2011 Census Outputs Policy and Analysis
Office for National Statistics
Contact
