Research data can be divided into primary material and data.
Primary material is any material (e.g. biological material, notes, interviews, texts and literature, digital raw data, recordings, etc.) that forms the basis of the research.
Data are detailed records of the primary materials that comprise the basis for the analysis that generates the results.
Source: Ministry of Higher Education and Science (2014) Danish Code of Conduct for Research Integrity.
Who generated the data?
With what objective is the data generated? Does it tell you about the context in which the data should be situated?
What methods, procedures or tools were used in the data collection or data generation?
Is there a data collection protocol, interview manual or other information that describes in detail the creation of this data?
How are data modified, adjusted, annotated, and are these changes documented?
Where did you find the data and how trustworthy is that source?
Which license conditions are in place to use the data?