Recent advances in cyclic perturbation of frequency tables

Abstract

As part of statistical disclosure control data holders can only distribute confidential data being sufficiently protected meeting national and institutional legislation. When releasing frequency tables to users, data holders usually apply what are called pre- and post-tabular methods reviewing both diclosure limitation and the users’ requirements. The main characteristic of post-tabular methods is to compute tables on the basis of their original underlying microdata and to perturb them just before transmission to users. The method of cyclic perturbation, proposed in (Duncan and Roehrig, Database Technologies: concepts, methodologies, tools and applications, pp 1823–1843, 2007), is very promising. Here, a sequence of perturbation patterns is added consecutively to some original table following a certain stochastic procedure. The paper presents different variations to define that sequence and discusses appropriate parameter settings in order to balance out the conventional trade-off between data utility and disclosure risk.