Metadata is additional structured information that describes the specific (research) data. They are used to publish data, make it findable, and cite it. Metadata for research data usually contain technical, legal, and administrative information (such as data volume, data format, and licenses). They might also include descriptive and subject specific information (such as data author, title, subject, short description and keywords). The description can be based on controlled vocabularies and thesauri, which ensure better findability. Subject-specific vocabularies can be researched on Bartoc.org.

 Some disciplines have established specific documentation and metadata standards (see, for example, the overviews of the Research Data Alliance and the Digital Curation Centre). If these are not available in your field of research, generic standards, such as the DataCite Metadata Standard, are a good choice.

The repository of the Freie Universität Berlin Refubium allows the following metadata fields for your research data in addition to extensive voluntary information: Author of the data, main title, year of publication, department/institution, language, resource type, abstract, Dewey Decimal Classification, and free keywords.

This structured data description is usually created during the research process as an additional file in a table or in a database or – if possible – inserted within the data to be described (e.g., TEI-XML, TIFF).

In addition to maintaining metadata in German, it is also advisable to produce English-language metadata so that the data can be found, understood, and reused internationally when published. If the data itself is available in another language, this language should also be used in the metadata.