A data management plan is a document which outlines how data will be managed throughout the whole project life cycle. Generally a plan covers initial decisions, how data will be handled during the active phase of research, and longer-term questions of preservation and sharing. The plan may be updated and revised as a project develops.
Even when not explicitly required by a funding body, a DMP is well worth creating. The planning process is a chance to think through what's needed to allow the project to run as smoothly as possible. It can also help anticipate possible problems before they occur – meaning that solutions can be found in good time.
Many aspects of data management are straightforward if they’re planned for from the beginning, but much harder to do retrospectively. Making a plan will therefore often save time and reduce stress later in the project.
Planning ahead can bring particular benefits when it comes to preparing data for sharing. For example, documenting what’s happened to data can be done quickly and easily if good recording processes are built into the research methodology; trying to unpick what’s been done later on is likely to be much more arduous.
Having a solid plan also means you're better prepared for unforeseen developments. Having thought through all the relevant issues means you're less likely to be taken by surprise - and you'll be better placed to respond if the unexpected does crop up.