Scopus Database

CiteScore = (citations in year Y to documents published in Y-3, Y-2, Y-1, Y) ÷ (documents published in Y-3, Y-2, Y-1, Y). For example, CiteScore 2024 = citations in 2024 to 2021–2024 documents ÷ total 2021–2024 documents. This differs from Impact Factor, which uses a 2-year window and counts only 'citable' articles. CiteScore values are typically 2–5 for respected journals (higher than comparable Impact Factors due to the longer window and broader document count). Use CiteScore for fair journal comparisons within Scopus; do not directly compare CiteScore to Impact Factor.

SJR (SCImago Journal Rank) is a prestige-weighted impact metric where citations from high-SJR journals count more heavily than citations from low-SJR journals. This mirrors the PageRank algorithm: being cited by a prominent journal is worth more than being cited by an obscure journal. SJR ranges typically 0.1–0.9. High-SJR journals tend to be well-established and heavily cited themselves. SJR accounts for field differences better than raw citations. Use SJR to identify high-quality journals and to compare impact across disciplines where citation counts vary widely.

WoS indexes ~21,000 journals with stricter inclusion criteria and deeper historical coverage (back to 1900s). Scopus indexes ~6,500 journals but covers 37 million documents total, including more open-access journals, conference proceedings, books, and recent publications. WoS is stronger for traditional disciplines (physics, chemistry, medicine) and long-term research trends. Scopus is broader in coverage of emerging fields, social sciences, and interdisciplinary research. For comprehensive systematic reviews, use both databases to avoid missing relevant sources.

Different databases index different document sets and publication types. A researcher's h-index in Scopus may differ from WoS h-index because: (1) Scopus includes more document types (conference papers, books), changing the ranking of papers by citation count; (2) coverage dates differ (Scopus starts ~1996, WoS includes earlier work); (3) indexing lag means newly published citations appear in one database before another. Report h-index using the specific database cited and note the calculation date. Do not compare h-indices across databases.

Yes, Scopus is suitable for systematic reviews, especially in multidisciplinary topics, emerging fields, or if you need open-access publication coverage. However, PRISMA guidelines recommend using both WoS and Scopus to ensure comprehensive coverage, as each database has unique strengths. Scopus excels for recent articles and grey literature; WoS excels for historical coverage and classical papers. Document your search strategy, database, date range, and number of results at each screening stage in your PRISMA-P protocol to ensure reproducibility.

SNIP (Source Normalized Impact Per Paper) = (CiteScore in a journal) ÷ (average CiteScore for papers in that journal's research field). SNIP controls for citation patterns unique to each field. If a field receives few citations on average (e.g., mathematics), a journal with 2 average citations per article may have high SNIP. If a field receives many citations (e.g., biomedics), the same 2 citations per article would yield low SNIP. SNIP of 1.0 means a journal has average impact for its field; >1.0 means above-average; <1.0 means below-average. Use SNIP to compare impact fairly across different disciplines.