CELL SUPPRESSION METHODOLOGY - THE IMPORTANCE OF SUPPRESSING MARGINALTOTALS

Safeguarding confidential information is of paramount concern to gover nment agencies in publishing statistical data. Given a set of sensitiv e cells, the problem is to identify a set of complementary cells to su ppress so as to mask the values of the sensitive cells. All of the exi sting cell suppression methods fail to consider the relationships amon g cell values and the representation of these relationships in margina l totals. That marginal totals may contain potent information has not been appreciated. This paper employs the theory of nominal data analys is to demonstrate that the disclosure of marginal totals can be very r isky. It recommends adding a front-end test to the existing methods. T he goal is to identify a list of sensitive marginal totals that have t o be suppressed. This increases the sophistication of cell suppression methodology by providing an extra layer of protection.