Limited privacy protection and poor sensitivity: Is it time to move on from the statistical linkage key-581?

Abstract

Background: The statistical linkage key (SLK-581) is a common tool for record linkage in Australia, due to its ability to provide some privacy protection. However, newer privacy-preserving approaches may provide greater privacy protection, while allowing high-quality linkage. Objective: To evaluate the standard SLK-581, encrypted SLK-581 and a newer privacy-preserving approach using Bloom filters, in terms of both privacy and linkage quality. Method: Linkage quality was compared by conducting linkages on Australian health datasets using these three techniques and examining results. Privacy was compared qualitatively in relation to a series of scenarios where privacy breaches may occur. Results: The Bloom filter technique offered greater privacy protection and linkage quality compared to the SLK-based method commonly used in Australia. Conclusion: The adoption of new privacy-preserving methods would allow both greater confidence in research results, while significantly improving privacy protection.