The curation process for Web of Science Core Collection™ is unique: our editorial decisions are conducted by our expert in-house editors who have no affiliations to publishing houses or research institutes thus removing any potential bias or conflict of interest.
Each editor is focused on specific subject categories enabling them to gain a deep, nuanced knowledge of the journals in that field. This level of in-house editorial curation contrasts sharply with methods used to create other databases that rely on predominantly algorithmic approaches and/or delegate aspects of editorial decision making to the research community.
The basic principles of our selection process remain the same: objectivity, selectivity and collection dynamics. We use a single set of 28 criteria to evaluate journals; these are divided into 24 quality criteria designed to select for editorial rigour and best practice at the journal level, and four impact criteria designed to select the most influential journals in their respective fields using citation activity as the primary indicator of impact.
Journals that meet the quality criteria enter Emerging Sources Citation Index™ (ESCI). Journals that meet the additional impact criteria enter Science Citation Index Expanded™ (SCIE), Social Sciences Citation Index™ (SSCI) or Arts & Humanities Citation Index (AHCI) depending on their subject area.
These are dynamic collections subject to continuous curation to ensure journals are in the appropriate collection. ESCI journals that gain impact move to SCIE, SSCI or AHCI. Similarly, SCIE, SSCI and AHCI journals that decrease in impact move to ESCI. Any journal that fails to meet the 24 quality criteria will be removed from the Web of Science Core Collection. Journals in ESCI are re-evaluated for possible inclusion in SCIE, SSCI or AHCI when their citation activity indicates that the impact criteria may be met, regardless of the time since their last evaluation. Our current strategy is to re-evaluate ESCI journals that map to the top half of their relevant flagship category. In this process journals are re-evaluated for quality first and impact evaluation is subject to quality being met. If both quality and impact criteria are met, the journals move to a flagship collection. The Web of Science editorial team focuses on new evaluations during the first half of the year, the second half is dedicated to re-evaluations. Covered journals are continuously evaluated for quality.
If concerns are raised regarding an indexed journal, either by users or through monitoring by our in-house editors, the journal will be re-evaluated according to our selection criteria. Where significant concerns are raised about the quality of the content published by the journal, new content will not be indexed during the course of the re-evaluation. When the evaluation is complete, the publisher will be informed of the outcome and the journal will either:
- be removed from coverage if it no longer meets the quality criteria
- or remain covered if it continues to meet the quality criteria.
If the journal meets the quality criteria, any missing content will be indexed. If the journal is removed from coverage, content will not be backfilled. In the most serious cases of breaches in the journal’s editorial standards, as determined by our selection criteria, published content may be removed from Web of Science™. Timeframes for completing a re-evaluation will depend on the particular circumstances of each case.
- Science Citation Index Expanded (SCIE): clinical, natural and applied sciences
- Social Sciences Citation Index (SSCI): social sciences
- Arts & Humanities Citation Index (AHCI): arts and humanities
- Emerging Sources Citation Index (ESCI): all disciplines
- Book Citation Index (BKCI): all disciplines
- Conference Proceedings Citation Index (CPCI): all disciplines