Rethinking rank swapping to decrease disclosure risk

Nowadays, the need for privacy motivates the use of methods that allow to protect a microdata file both minimizing the disclosure risk and preserving the data utility. A very popular microdata protection method is rank swapping. Record linkage is the standard mechanism used to measure the disclosure risk of a microdata protection method. In this paper we present a new record linkage method, specific for rank swapping, which obtains more links than standard ones. The consequence is that rank swapping has a higher disclosure risk than believed up to now. Motivated by this, we present two new variants of the rank swapping method, which make the new record linkage technique unsuitable. Therefore, the real disclosure risk of these new methods is lower than the standard rank swapping. © 2007 Elsevier B.V. All rights reserved.Partial support by the Spanish MEC (projects ARES – CONSOLIDER INGENIO 2010 CSD2007-00004 – and eAEGIS – TSI2007-65406-C03-02) is acknowledged. Jordi Nin wants to thank the Spanish Council for Scientific Research (CSIC) for his I3P grant. Appendix APeer Reviewe