Question to the Ministry of Justice:

To ask the Secretary of State for Justice, whether probabilistic record linkage tools, used by the Department or its agencies automatically link records relating to individuals where a predefined confidence threshold is met; and what human review is undertaken before such linked records are used for operational purposes.

The Ministry of Justice uses Splink, a probabilistic record linkage tool created in the Department, across a variety of services and analytical applications.

Where the match score exceeds a certain threshold, records are typically linked automatically, without human review. The score threshold varies according to use case and is set following assessment of accuracy required for the intended purpose, including where linked records may support operational processes.

Before a linking model is deployed, human review is undertaken on a sample of recorded pairs to assess linkage accuracy inform selection of an appropriate confidence threshold. Linkage performance is subsequently monitored, and threshold and matching algorithms are adjusted where necessary in response to identified issues or changes in data quality.

In addition, record linkage projects are subjected to appropriate governance and ethical overview, including through the Ministry of Justice AI and Data Science Ethics Framework.