A Data Management Plan (DMP) is a document that describes the types of data that will be produced as part of a research project and how those data will be securely stored, documented, shared, and preserved both during and after the project is completed. Federal grant agencies, such as the National Science Foundation (NSF), the National Institute of Health (NIH), and the National Endowment for the Humanities (NEH) require DMPs (or data sharing plans) to be submitted when applying for certain grants (all grants in the case of NSF).
The specific requirements vary by granting agency and directorate.
Specific requirements will vary by agency, but in general a DMP requires you to describe the specific data that will be produced, how you will document the data, how the data will be stored and protected during the research, and how you plan to share and preserve your data after the research is completed. See the Library's Data Management Plan page for templates and more details.
Example Data Management Plans:
UK Data Archive’s Managing and Sharing Data document