"Is the journal SCI, Scopus, or just ESCI?" For researchers, the answer to this question affects everything from tenure to incentive points — yet the index acronyms are constantly mixed up. For a sense of scale: in Peerfect's 13,524-journal corpus, the estimated distribution shows Scopus 6,224, SCI 2,667, SSCI 1,216, ESCI 803 and TR Dizin (likely) 1,081 journals (Academic Publishing Landscape 2026). This guide cleanly separates what SCIE, SSCI, AHCI, ESCI and Scopus are, which metric each one uses, and how "valuable" each is treated in practice.
SCI, SCIE, SSCI, AHCI: what are the Web of Science indexes?
All four acronyms live under one roof: the Web of Science (WoS) Core Collection, run by Clarivate. The difference between them is essentially the discipline:
- SCIE (Science Citation Index Expanded) — natural and applied sciences. The current, expanded form of the old narrow "SCI"; when people say "SCI" they usually mean this.
- SSCI (Social Sciences Citation Index) — social sciences.
- AHCI (Arts & Humanities Citation Index) — arts and humanities.
These three are considered the "core" citation indexes of WoS and traditionally form the most prestigious tier. If a journal is in one of them, it receives a Journal Impact Factor and a quartile (Q1–Q4) in its discipline via Journal Citation Reports (JCR).
What is ESCI, and why is it called a "waiting room"?
ESCI (Emerging Sources Citation Index) is also part of the Web of Science Core Collection, but it has a different role: it covers new or emerging journals that have passed WoS quality control but do not yet meet the full criteria of SCIE/SSCI/AHCI. That's why it's often described as a "waiting room" — a journal can be promoted to one of the core indexes as it proves its performance.
An important update: in 2023, Clarivate began assigning a Journal Impact Factor to all WoS Core Collection journals, including ESCI and AHCI. So saying "an ESCI journal can't have an Impact Factor" is now wrong. Even so, many institutional criteria still place ESCI in a lower tier than the core three.
How is Scopus different from Web of Science?
Scopus is not a product of the same organization as Web of Science: it is run by Elsevier and is an entirely separate database. The key differences:
- Coverage: Scopus is generally broader, including more journals and regional titles. The Web of Science Core Collection is considered more selective.
- Metric: Scopus uses CiteScore (and SJR), not the Impact Factor, and computes its quartiles from those metrics.
- A journal can be in both. SCIE and Scopus are not mutually exclusive; many journals are indexed in both WoS and Scopus.
Impact Factor or CiteScore — which metric belongs to which?
Both metrics measure a similar idea (the average number of citations a journal's articles receive) but rely on different databases and calculation windows. To keep them straight:
| Index | Run by | Coverage | Main metric |
|---|---|---|---|
| SCIE | Clarivate (Web of Science) | Natural & applied sciences | Journal Impact Factor (JCR) |
| SSCI | Clarivate (Web of Science) | Social sciences | Journal Impact Factor (JCR) |
| AHCI | Clarivate (Web of Science) | Arts & humanities | Journal Impact Factor (since 2023) |
| ESCI | Clarivate (Web of Science) | All fields — emerging | Journal Impact Factor (since 2023) |
| Scopus | Elsevier | Very broad, all fields | CiteScore & SJR |
A journal claiming a "high Impact Factor" doesn't automatically put it in WoS; always verify which source the metric comes from.
Which index counts for more in tenure and incentives?
This varies by country and institution, and the exact weights change year to year — so the only binding source is your institution's current promotion/incentive criteria. As a general pattern, SCIE / SSCI / AHCI journals tend to carry the most weight, ESCI and Scopus sit in the middle, and national indexes (such as Türkiye's TR Dizin) form a separate category.
The lesson: choose a journal not just because it is "internationally indexed," but based on which category it falls into under your specific criteria. A journal in the wrong category may not earn the points you expect, even if your paper is accepted.
How do you verify which index a journal is really in?
Verify the claim at the source, not on the journal's page:
- For Web of Science: the Clarivate Master Journal List (mjl.clarivate.com) — you can see which collection (SCIE/SSCI/AHCI/ESCI) lists the journal.
- For Scopus: Elsevier's official Scopus source list.
- If a journal claims "SCI indexed" on its own site but doesn't appear on these lists, the claim isn't credible — it's one of the most common predatory-journal tactics.
Checking the right index and quartile journal by journal takes time. Peerfect's free journal recommendation engine puts journals that fit your paper's scope in front of you together with their index and quartile information, so you see both the right category and the right venue at a glance. Which index is "valuable" for you is set by your institution's criteria — the rest is about choosing the right journal from the start.