Last Updated on July 1, 2026 by Dr. Bhagat
JOURNAL METRICS·Updated June 2026
SCI Journal Impact Factor 2025 covers the Science Citation Index with 9,500+ journals. Top SCI journal: CA: A Cancer Journal for Clinicians with IF 685.2. Full JCR 2025 rankings, quartile data, and SCI vs SCIE comparison.
Key Takeaways
- SCI Definition: The Science Citation Index (SCI) is a multidisciplinary database maintained by Clarivate Analytics that indexes high-quality scholarly journals in the sciences.
- Publisher: Clarivate Analytics owns and maintains the SCI as part of the Web of Science Core Collection.
- JCR Release: The 2025 Journal Citation Reports (JCR) were released on June 20, 2025, covering the 2024 citation year.
- Top SCI Journals 2025: CA: A Cancer Journal for Clinicians (685.2), Nature Reviews Molecular Cell Biology (118.0), The Lancet (109.0).
- SCI vs SCIE: SCIE (Science Citation Index Expanded) is the online version of SCI. Since 2020, Clarivate has unified both under the SCIE name in the Web of Science Core Collection.
- Evaluation: Journals in SCI/SCIE are assessed on 24 quality criteria including citation behavior, peer review rigor, and editorial standards.
OVERVIEWWhat Is the Science Citation Index (SCI)?
The Science Citation Index (SCI) is a multidisciplinary bibliographic database maintained by Clarivate Analytics as part of the Web of Science Core Collection. Originally created by Eugene Garfield at the Institute for Scientific Information (ISI) in 1964, SCI indexes peer-reviewed scholarly journals across the natural sciences, physical sciences, life sciences, and engineering. The database serves as the foundational source for Journal Impact Factor calculations published in the Journal Citation Reports (JCR).
SCI journals are selected through a rigorous evaluation process that assesses editorial quality, citation impact, international diversity, and publishing standards. Inclusion in SCI signals that a journal meets Clarivate’s established criteria for scientific rigor and citation influence.
CRITERIAEvaluation Criteria for SCI Indexed Journals
Clarivate evaluates journals for SCI inclusion against 24 quality criteria organized across three dimensions:
- Editorial Standards: Peer review quality, international editorial board composition, ethical oversight, author guidelines clarity, and transparency of publishing processes.
- Citation Behavior: Citation velocity, international citation diversity, self-citation ratio, and citation impact relative to field norms.
- Publishing Standards: Publication timeliness, content originality, English language abstracts, consistent bibliographic information, and ISSN registration.
Journals that pass evaluation are added to the Web of Science Master Journal List. SCIE journals that demonstrate sustained high citation impact may be promoted to SCIE (the current unified standard).
COMPARISONWhat Are SCI and SCIE?
The Science Citation Index (SCI) originally existed as a print product. The Science Citation Index Expanded (SCIE) launched as the electronic version with broader journal coverage. In 2020, Clarivate unified both indices under the SCIE designation within the Web of Science Core Collection. Today, SCIE represents the comprehensive science index in Web of Science.
| Feature | SCI (Legacy) | SCIE (Current) |
|---|---|---|
| Format | Print (historical) | Electronic (online) |
| Coverage | ~3,500 journals (peak) | ~9,500+ journals |
| Current Status | Unified into SCIE (2020) | Active index in Web of Science |
| Impact Factor | Eligible | Eligible |
| Publisher | Clarivate Analytics | Clarivate Analytics |
COMPARISONWhich Is Better: SCI or SCIE?
Since Clarivate unified SCI into SCIE in 2020, the distinction is largely historical. Modern researchers should focus on whether a journal is indexed in the Web of Science Core Collection (which uses the SCIE designation) rather than distinguishing between SCI and SCIE. Both indices use the same evaluation criteria and confer the same level of recognition for Impact Factor eligibility.
Some academic institutions, particularly in certain countries, may still reference “SCI journals” in their evaluation criteria. In these contexts, SCIE-indexed journals fulfill the same requirements, as SCIE is the current and expanded form of the original SCI.
METRICSWhat Is JCR?
The Journal Citation Reports (JCR) is an annual publication by Clarivate Analytics that provides citation metrics for journals indexed in the Web of Science Core Collection, including SCIE and SSCI journals. JCR publishes the Journal Impact Factor (JIF), 5-Year Impact Factor, Immediacy Index, Eigenfactor Score, and Article Influence Score for each indexed journal.
The 2025 JCR release (covering the 2024 citation year) was published on June 20, 2025. JCR data is used by academic institutions, funding agencies, and governments worldwide to evaluate journal quality and research impact.
COMPARISONWhich Is Better: SCI or ESCI?
The Emerging Sources Citation Index (ESCI) was launched in 2015 as a preliminary evaluation index for journals under consideration for SCIE/SSCI inclusion. Key differences include:
- Impact Factor: ESCI journals did not receive Impact Factors until the 2023 JCR release (in 2024), when Clarivate began ranking ESCI journals alongside SCIE/SSCI journals.
- Quartile Ranking: ESCI journals now receive JCR quartile assignments (Q1-Q4) following the 2024 JCR policy update.
- Selection Criteria: ESCI journals meet basic quality standards but have not yet demonstrated the citation impact required for SCIE inclusion.
- Promotion Path: ESCI journals that demonstrate sustained citation impact may be promoted to SCIE during annual journal evaluations.
For manuscript submission decisions, SCIE-indexed journals generally carry more established reputations than ESCI journals, though the gap has narrowed following the 2024 ranking policy changes.
