Last Updated on July 16, 2026 by Dr. Bhagat
Indexing & Databases·Updated June 2026
SCI vs SCIE vs ESCI: Understanding the Web of Science Indexes
Three similar-sounding acronyms with very different meanings for your career. Here is exactly what each index signals.
OverviewThe Web of Science index hierarchy
Web of Science is not a single database but a platform of interconnected indexes. The three most relevant to science, engineering, and medicine are:
SCI — the original Science Citation Index, now largely superseded by SCIE. SCIE — the expanded, current primary science index. ESCI — the Emerging Sources Citation Index, a “watch list” for new journals.
SCI & SCIEWhat they are and how they differ
SCI was the original index created by Eugene Garfield in the 1960s. It was a relatively small, highly selective list of core science journals. In the 1990s, Clarivate expanded it into SCIE, which now includes the vast majority of journals that were in SCI plus thousands more.
Today, SCI is largely a historical label. When researchers or institutions say “SCI-indexed,” they almost always mean SCIE. Journals in SCIE receive an Impact Factor and are ranked in JCR quartiles.
ESCIThe emerging sources index
ESCI was launched in 2015 as a pathway index for journals that show promise but do not yet meet the full editorial standards for SCIE. It allows Clarivate to monitor new and regional journals before deciding whether to promote them.
Journals in ESCI do not receive an Impact Factor. They are indexed in Web of Science and are searchable, but they are not ranked in JCR. Inclusion in ESCI is a positive signal — it means the journal is under formal evaluation — but it is not equivalent to SCIE status.
Some journals claim “Indexed in Web of Science” without specifying which index. Always verify whether the journal is in SCIE (which gets an Impact Factor) or ESCI (which does not). This distinction matters enormously for tenure, grants, and institutional evaluation.
| Index | Full name | Selectivity | Impact Factor? | Typical use |
|---|---|---|---|---|
| SCI | Science Citation Index | Historical, very selective | Yes (via SCIE) | Legacy reference |
| SCIE | Science Citation Index Expanded | High | Yes | Tenure, grants, JCR ranking |
| ESCI | Emerging Sources Citation Index | Moderate | No | Pathway to SCIE evaluation |
Source: Web of Science Core Collection documentation, Clarivate 2025.
PathwayHow journals move between indexes
Clarivate regularly evaluates journals across all indexes. A journal in ESCI may be promoted to SCIE if it demonstrates strong editorial standards, consistent publication, and meaningful citation impact. Conversely, a journal in SCIE may be demoted to ESCI — or even removed entirely — if its standards decline.
Clarivate publishes an annual coverage list update each June, announcing additions and removals from each index.
Key Takeaways
- SCIE is the current primary science index; SCI is largely historical.
- Only SCIE and SSCI journals receive an Impact Factor.
- ESCI is a pathway index for emerging journals; no Impact Factor is assigned.
- Always verify which specific index a journal is in, not just “Web of Science.”
- Journals can be promoted or demoted between indexes annually.
FAQPeople also ask
Is SCI the same as SCIE?
Not exactly. SCI was the original, smaller index. SCIE expanded it and is now the primary science index. For practical purposes, “SCI-indexed” almost always means SCIE today.
Do ESCI journals have an Impact Factor?
No. Only journals in SCIE (and SSCI, AHCI) receive an Impact Factor. ESCI journals are tracked but not ranked in JCR.
How do I check which index a journal is in?
Use the Web of Science Master Journal List at mjl.clarivate.com. Search by journal name or ISSN, and the record will show which index(es) it appears in.
Can a journal be in both SCIE and ESCI?
No. A journal is in one or the other (or neither). ESCI is a separate evaluation tier below SCIE.
Is ESCI a bad thing for a journal?
No. ESCI inclusion is a positive signal that a journal is under formal evaluation by Clarivate. It is a step toward potential SCIE inclusion, not a black mark.
SourcesReferences & further reading
- Web of Science Master Journal List — Verify index membership.
- Clarivate Analytics — Official Web of Science documentation.
- Scopus vs Web of Science — Database comparison.
FAQFrequently Asked Questions About SCI, SCIE, and ESCI
Is ESCI a “real” Web of Science index?
Yes, ESCI is an official Web of Science index. However, it is less selective than SCIE. Journals in ESCI do not receive an Impact Factor and are not counted in JCR rankings. ESCI serves as an evaluation pathway toward potential SCIE inclusion.
Can a journal move from ESCI to SCIE?
Yes. Journals in ESCI are regularly evaluated. Those that demonstrate consistent quality, citation impact, and editorial standards may be promoted to SCIE and receive an Impact Factor. Conversely, SCIE journals can be demoted to ESCI if their performance declines.
Do SCI and SCIE journals both have Impact Factors?
SCIE is the successor to SCI. SCI was discontinued as a separate index, and its journals were integrated into SCIE. All journals currently in SCIE receive an Impact Factor through JCR. ESCI journals do not.
Career GuideHow These Indexes Affect Your Academic Career
For PhD students: Publishing in SCIE journals is typically expected for thesis chapters. ESCI journals may be acceptable for supplementary work — check your university’s guidelines.
For promotion (API/CAS): Indian researchers should target SCIE journals for maximum scoring. ESCI publications may receive partial credit depending on institutional policy.
For international applications: SCIE journals carry the most weight globally. ESCI publications demonstrate emerging quality but lack the established reputation of SCIE-indexed venues.
Pro Tip: Track a target ESCI journal’s citation trends. Journals approaching SCIE promotion often show rapidly increasing citation metrics — publishing just before promotion can be strategic.