What is pseudonymised data?

Pseudonymisation is a process of removing directly identifiable data from a dataset (such as a name, NHS number) and replacing that with a code. A dataset that has been pseudonymised presents less risk as the ability to identify an individual has been reduced, although not removed. This is common practice in healthcare research as it reduces the risk but can still facilitate updating of data over time and linking data between datasets. Pseudonymised data is still considered identifiable if the link between the original data and the code created is held by the organisation.