Definition: Cell suppression
In tabular data the cell suppression SDC method consists of primary and complementary (secondary) suppression. Primary suppression can be characterised as withholding the values of all risky cells from publication, which means that their value is not shown in the table but replaced by a symbol such as "χ" to indicate the suppression. According to the definition of risky cells, in frequency count tables all cells containing small counts and in tables of magnitudes all cells containing small counts or presenting a case of dominance have to be primary suppressed. To reach the desired protection for risky cells, it is necessary to suppress additional non-risky cells, which is called complementary (secondary) suppression. The pattern of complementary suppressed cells has to be carefully chosen to provide the desired level of ambiguity for the risky cells with the least amount of suppressed information.
ESSNet SDC (Network of Excellence in the European Statistical System in the field of Statistical Disclosure Control), under the coordination of Anco HUNDEPOOL, "Handbook on Statistical Disclosure Control", version 1.2 (2010 Edition)