Secondary use of data occurs when data is extracted from its primary context of origin, combined with other data, and used for further, secondary purposes.

The great economic value of data lies in such secondary uses, as demonstrated by platforms such as Google, Facebook, and Amazon, whose business models are essentially based on the accumulation and reuse of data. But the secondary use of data also plays a crucial role in virtually all areas of science, for verifying research results or gaining new scientific insights.

The term "secondary use of data" must be distinguished from the broader term "data management." Data management encompasses all technical, organizational, and legal aspects of the data lifecycle—from data collection, management, and storage to archiving or destruction. The preparation and publication of data for secondary use is one aspect of the data life cycle.