Person Linkage Spine

The Person Linkage Spine is central to our data linking methods. Instead of linking datasets one-to-one for individual projects, we can link all datasets to the Spine once and then combine datasets via the Spine as needed for multiple projects. The Spine enables more efficient and higher quality linkage. By keeping the Spine separate from the main body of the data, we also improve privacy and security.

The Spine is based on the combined population from three core datasets: 

• Medicare Consumer Directory (MCD) - Services Australia
• DOMINO Centrelink Administrative Data (DOMINO CAD) - Department of Social Services
• Personal Income Tax (PIT) - Australian Taxation Office

The Spine aims to cover all people who were resident in Australia at any point during a given reference period. The current Spine covers January 2006 to June 2025.

For the first time in 2025, the Spine was constructed using Splink, a probabilistic linkage tool that estimates the likelihood that records from different sources refer to the same person. This method delivered significant processing efficiencies while maintaining linkage quality comparable to previous deterministic approaches. The overall Spine structure remains consistent with previous versions.

Ongoing work on the Spine falls into two categories:

• Updating with more recent data (Spine maintenance) - conducted at least annually.
• Assessing quality and researching other data sources to improve quality and coverage of the Australian population - this may include bringing in new core datasets in the long term.

As an enduring piece of data infrastructure, the Spine enables us to undertake current and future research projects in a consistent and efficient way, that minimises replication of linkage effort. Improving Spine quality leads to the outputs of research projects being more accurate.

A higher quality Spine supports more precise integrated data outputs, that provide researchers with exactly the data they're interested in. This makes the researcher's job easier and protects privacy.

For a list of datasets linked using the Spine, and possible future linkages, see the PLIDA data and legislation page.