Barnardisation

Barnardisation is a method of disclosure control for tables of counts that involves randomly adding or subtracting 1 from some cells in the table.

It is named after Professor George Alfred Barnard (1915–2002), a professor of mathematics at the University of Essex.

In the United Kingdom, barnardisation is sometimes employed by public agencies in order to enable them to provide information for statistical purposes without infringing the information privacy rights of the individuals to whom the information relates. The question whether barnardisation may fall short of the complete anonymisation of data and the status of barnardised data under the complex provisions of the Data Protection Act 1998 were considered by the House of Lords in the case of Common Services Agency v Scottish Information Commissioner [2008] 1 WLR 1550, the above case is also reported at All ER 2008 (4) 851.
References

Office For National Statistics - Review of the Dissemination of Health Statistics: Confidentiality Guidance Working Paper 3: Risk Management http://www.ons.gov.uk/ons/guide-method/best-practice/disclosure-control-of-health-statistics/working-paper-3--risk-management.pdf

Mathematics Encyclopedia