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

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.

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.

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.

The Bloom filter technique offered greater privacy protection and linkage quality compared to the SLK-based method commonly used in Australia.

The adoption of new privacy-preserving methods would allow both greater confidence in research results, while significantly improving privacy protection.