In the context of data transfer, the anonymity of research data plays a significant legal role. Data anonymity can be categorized into absolute anonymity, factual anonymity, and formal anonymity. You can find more information in the corresponding article on legal information.
The degree of data anonymization may also depend on the access pathway. You can find relevant information under Access & Reuse.
To make the data preparation effort transparent, you can provide third parties with appropriate process information, such as, for example, guidelines for data processing, data preparation etc.
Checklist
How are the data transferred?
Are these sensitive data that require special data transfer procedures?
Have the rights and obligations between the participating researchers and research data center staff been clarified?
Is there a transfer agreement in place?
Are there internal institutional guidelines for transfer documentation and/or error handling?
[Adapted from: Ludwig, Jens; Enke, Harry (Eds.) (2013): Guide to Research Data Management. Guidelines from the WissGrid Project. Glückstadt: VWH Verlag Werner Hülsbusch Publisher for Media Technology and Business.]