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ESSNet on Statistical Disclosure Control |
Contact:Peter-Paul de WolfStatistics Netherlands P.O. Box 24500 2490 HA The Hague The Netherlands Phone: +31 70 337 5060 
Last update: 10 Oct 2011 |
Task 6. Improvement of software for tabular data
6.a Protection of frequency tables and magnitude tables with negative valuesFor frequency tables the main problem lies in the formulation of a good and accepted set of rules. At the moment it is anticipated that the current cell suppression and rounding procedures are adequate but a discussion of the rules will be included in the handbook.A much more urgent problem is the protection of magnitude tables with also negative values. The assumption under the current sensitivity rules (p% but also dominance rule) is non-negativity of the cell values (or even the individual contributions). Extensions of the sensitivity rules or at least rules for finding the primary unsafe cells are needed. Different approaches for tables with only a few negative cells and more general situations will be considered. Partners: DE, NL, UK Deliverables: We foresee a report in year 1 and based on that an implementation in the software in year 2. 
6.b. Inclusion of audit-routinesOne of the results of the CASC-project was an audit routine of protected tables, developed by the University of Ilmenau. The aim of such an audit-routine is to assess the feasibility of the suppression pattern of a protected table. The audit tool can be used to assess the quality of a protection pattern of a table and also gives insight to the ranges that can be derived for all suppressed cells. For Eurostat it could be a tool to check the consistency of tables, that are sent to them, but for which the protection pattern is computed by the member states.It should however be kept in mind that an audit routine can only assess the pattern given certain assumptions for a safe table. The current prototype is a Delphi program. It has to be decided whether we will link the current program to t arg or convert the program into a DLL. Partners: DE, CBS Deliverables: Inclusion in τ-ARGUS, test version in year 1 final version in year 2.
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