According to the OECD, research data is all material that was recorded and used as a primary source during scientific research, and which is commonly accepted by the scientific community as necessary to validate the results of the research. A data set constitutes a systematic and partial representation of the research topic.

It is considered as research data:

• laboratory notebooks,
• field notebooks,
• primary research data,
• questionnaires,
• audio tapes,
• videos,
• model development,
• photographs,
• films,
• digital objects,
• algorithms,
• scripts,
• databases,
• metadata and metadata schemas,
• software configurations, checks and test responses.

Software code used to generate, comment on or analyse the data may also be considered as data.

The following are not considered final research data: laboratory notes, partial data sets, preliminary analyses, drafts of papers, plans for future research, communications with colleagues, physical objects, laboratory specimens such as mice and laboratory specimens or strains of bacteria.

Data can be numerical, descriptive or visual.

Classification:

• According to their nature: qualitative or quantitative.
• According to their level of processing: raw (primary data), processed or analysed.
• According to their source: experimental (e.g. chromatographies), observational (e.g. surveys) or computational (obtained by simulation).
• According to their format: textual (Word, PDF, RTF...), numerical (Excel, CSV...), multimedia (JPEG, MPEG, WAV...), structured (XML, MySQL...), software code (Java, C...), specific to a software (Mesh, 3D CAD, statistical model...) or specific to a discipline or instrument.