Data Citation Index fully indexes a significant number of the world's leading data repositories of critical interest to the scientific community, including over two million data studies and datasets. The records for the datasets, which include authors, institutions, keywords, citations and other metadata, are connected to related peer-reviewed literature indexed in the Web of Knowledge.
- Data repository: a database or collection comprising data studies, data sets and/or microcitations which stores and provides access to the raw data. Constituent data studies, and sometimes individual data sets, are marked up with metadata providing a context for the available raw data.
- Data study: description of studies or experiments held in repositories with the associated data which have been used in the data study. (Includes serial or longitudinal studies over time). Data studies can be a citable object in the literature and may have cited references attached in their metadata, together with information on such aspects as the principal investigators, funding information, subject terms, geographic coverage etc. The level of metadata provided varies between repositories.
- Data set: a single or coherent set of data or a data file provided by the repository, as part of a collection, data study or experiment. Data sets may present in a number of file formats and media types: they may be number based files such as spreadsheets, images, video, audio, databases etc. Data sets can be a citable object in the literature and may have cited references attached in their metadata, but more commonly they inherit the metadata of the overall study in which they are used.