At a broad level, data are items of recorded information considered collectively for reference or analysis.

Data can occur in a variety of formats that include, but are not limited to,

• notebooks
• survey responses
• software and code
• measurements from laboratory or field equipment (such as IR spectra or hygrothermograph charts)
• images (such as photographs, films, scans, or autoradiograms)
• audio recordings
• physical samples 

Data can be defined in a variety of ways, depending the discipline and the context. When it comes to making decisions about managing your research data, you may wish to consult the definitions used by your funder and by the University of Pittsburgh.

• University of Pittsburgh Guidelines on Research Data Management defines data in the second paragraph.
• NIH defines data in its Data Sharing Policy and Implementation Guidance.

Research data management (or RDM) is a term that describes the organization, storage, preservation, and sharing of data collected and used in a research project. It involves the everyday management of research data during the lifetime of a research project (for example, using consistent file naming conventions). It also involves decisions about how data will be preserved and shared after the project is completed (for example, depositing the data in a repository for long-term archiving and access).

There are a host of reasons why research data management is important:

• Data, like journal articles and books, is a scholarly product.
• Data (especially digital data) is fragile and easily lost.
• There are growing research data requirements imposed by funders and publishers.
• Research data management saves time and resources in the long run.
• Good management helps to prevent errors and increases the quality of your analyses.
• Well-managed and accessible data allows others to validate and replicate findings.
• Research data management facilitates sharing of research data and, when shared, data can lead to valuable discoveries by others outside of the original research team.

An important first step in managing your research data is planning. To get you started thinking about data management planning, here are some of the issues you need to consider:

• Your institution's and funding agency's expectations and policies
• Whether you collect new data or reuse existing data
• The kind of data collected and its format
• The quantity of data collected
• Whether versions of the data need to be tracked
• Storage of active data and backup policy and implementation
• Storage and archiving options and requirements
• Organizing and describing or labeling the data
• Data access and sharing
• Privacy, consent, intellectual property, and security issues
• Roles and responsibilities for data management on your research team
• Budgeting for data management

For more insight into the questions you should ask and answer, check out Data Management Checklist (UK Data Archive)