Scope and Coverage

Journal Coverage

Article counts for Essential Science Indicators are derived from 11,727 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. 

Journal List

The master journal list (application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, 782.5 kB, info), which comprises all active journal titles eligible for inclusion in Essential Science Indicators, has been updated as of January 18, 2019, to cover a 10-year plus 10-month period, January 1, 2008 – October 31, 2018. Data is updated bi-monthly (six times a year). This is the fifth bi-monthly period of 2018.

This master journal list will be updated regularly. The current extraction date is December 1, 2018. 

Item Selection

Papers are defined as regular scientific articles and review articles. Letters to the editor, corrections, abstracts, and retracted articles are excluded.

File Depth

The years shown in ESI reports are publication years, unless otherwise indicated. ESI indicators are calculated from 10-years plus 10-months of data.

ESI is updated six times a year. The most recent update may add documents published in the previous year, in which case metrics based on the previous publication year may be adjusted.

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10 Months