Avoiding the jigsaw effect: experiences with Ministry of Justice reoffending data

This briefing paper describes an approach to testing anonymised data prior to online release, in order to minimise the possibility of jigsaw identification or disclosure from the data together with supplementary data. A research challenge was posed to students of three universities, who were able to test a data release. Their progress enabled statisticians to understand the vulnerabilities of the anonymised data in more detail, and to act in order to contain them. In this way, transparency and privacy remain compatible.