HiTaS: A Heuristic Approach to Cell Suppression in Hierarchical Tables

The views expressed in this paper are those of the author and do not necessarily reflect the policies of Statistics Netherlands. This paper describes a heuristic approach to find suppression patterns in tables that exhibit a hierarchical structure in at least one of the explanatory variables. The hierarchical structure implies that there exist (many) sub-totals, i.e., that (many) sub-tables can be constructed. These sub-tables should be protected in such a way that they cannot be used to undo the protection of any of the other tables. The proposed heuristic approach has a top-down structure: when a table of high level (sub-)totals is suppressed, its interior turns into the marginals of possibly several tables on a lower level. These lower level tables are then protected while keeping the marginals fixed.