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GSS > Guidance > Methodology > Statistical Disclosure Control

Statistical Disclosure Control


Statistical disclosure control (SDC) is the term used to cover the many methods of safeguarding the confidentiality of the information held by the GSS about individuals and businesses. Information obtained from surveys or administrative data is usually given in confidence. SDC is applied to ensure that individuals, businesses or other statistical units cannot be identified from published data, whether record level data or tables.

Recent technological advances, along with the requirement for open data, have dramatically increased the volume of data available to companies and individuals. These advances have given the issue of disclosure control greater importance, with increasing accessibility translating into higher risk of successful identifications from published statistics.

Statistical disclosure control involves modifying data so that the risk of identification is reduced to an acceptable level. At a basic level, this involves reducing detail (recoding variables) or damaging the data (perturbing values). Disclosure control methods aim for an optimal balance between the improvement in confidentiality protection and the reduction in data quality.

Generally, rare combinations of attributes lead to the identification of individuals, for example, a sixteen-year-old widow or a single manufacturer in an area. Disclosure control methods are usually applied if ethical, practical or legal considerations require the data to be protected, and the possibility of identification exists.


A series of guidance documents on statistical disclosure control have been produced for GSS and GSR members. These cover tabular data produced both from administrative sources and surveys, and microdata produced form social surveys. Each set of guidance comprises a guidance document and a document containing case studies.

The National Statistician’s Guidance on Confidentiality of Official Statistics – provides guidance to all producers of official statistics on interpreting and implementing the Principles and Practices in the Code of Practice for Official Statistics which relate to the confidentiality of those statistics.

supportTraining & Support Services

The Statistical Disclosure Control Team at ONS are able to offer advice to GSS members. Depending on the amount of work involved, it may be necessary to discuss charging for it under the ONS Methodology Advisory Service arrangements.

Check out our Learning and Development page for further information on available training.