Evaluation of per-record identification risk and swappability of records in a microdata set via decomposable models

Abstract

We propose a strategy for disclosure risk evaluation and disclosure control of a microdata set based on fitting decomposable models of a multiway contingency table corresponding to the microdata set. By fitting decomposable models, we can evaluate per-record identification (or re-identification) risk of a microdata set. Furthermore we can easily determine swappability of risky records which does not disturb the set of marginals of the decomposable model. Use of decomposable models has been already considered in the existing literature. The contribution of this paper is to propose a systematic strategy to the problem of finding a model with a good fit, identifying risky records under the model, and then applying the swapping procedure to these records.