Essential Science Indicators (ESI)


Essential Science Indicators is a unique compilation of performance statistics and trends extrapolated from counts of articles published in scholarly journals and the citations to those articles.

Article counts for Essential Science Indicators are derived from 11,855 journals indexed in Web of Science Core Collection (Science Citation Index Expanded and Social Sciences Citation Index only) over a 10-year period. Citation counts for these articles are derived from journals indexed in Web of Science Core Collection (Science Citation Index Expanded, Social Sciences Citation Index and Arts & Humanities Citation Index)

Each journal is assigned to one of 22 research fields. In ESI, a journal can be assigned to only one field.  Journals such as Science and Nature are categorized as multidisciplinary since they publish research in many different fields. As a result, papers published in these multidisciplinary journals are assigned to a field based on the representation of the cited journals. For example, if the majority of cited references in the paper are to neuroscience journals, the paper is then categorized as neuroscience.