Impact Factor vs CiteScore: Which Matters More?

For decades, the journal impact factor was the only widely recognised metric for evaluating academic journals. Then Elsevier launched CiteScore through Scopus in 2016, offering a competing alternative with broader coverage, a longer citation window, and free access. Today, researchers, librarians, and institutions use both — but many are unclear about what exactly the difference is, when each is more reliable, and which one they should quote in grant applications and tenure packages. 

 This guide compares impact factor and CiteScore head-to-head, explains where they agree and disagree, and gives you a practical decision framework for using each one.

What Is Impact Factor? 

The Journal Impact Factor (JIF) is published annually by Clarivate Analytics through the Journal Citation Reports. It measures the average number of citations received per citable article published in a journal during the two preceding years. 

Formula: Citations in Year X to articles from Years X−1 and X−2 ÷ Citable articles (original research + reviews only) published in Years X−1 and X−2 

Database: Web of Science Core Collection 

Cost: Requires JCR subscription (institutional access available at most universities) 

Coverage: Approximately 21,000–22,000 journals 

Published since: 1975 

What Is CiteScore? 

CiteScore is a journal metric published annually by Elsevier through the Scopus database, launched in 2016 as a free, transparent alternative to the paywalled JIF. 

Formula: Citations in Years X, X−1, X−2, and X−3 to all documents published in those same years ÷ All documents published in those same years (including editorials, letters, and all other types) 

Database: Scopus 

Cost: Free (via Scopus journal search or journal homepages) 

Coverage: Approximately 27,000 journals — broader than JCR 

Published since: 2016 

Head-to-Head Comparison 

Feature	Impact Factor (JIF)	CiteScore
Published by	Clarivate Analytics	Elsevier
Database	Web of Science	Scopus
Citation window	2 years	4 years
Denominator document types	Articles and reviews only	All document types
Self-citations	Included	Included
Citation weighting	All citations equal	All citations equal
Cost to access	Requires subscription	Free
Journal coverage	~21,000–22,000	~27,000
Available since	1975	2016
Update frequency	Annual (June)	Annual

 

Where Impact Factor and CiteScore Agree 

For most major, well-established journals, JIF and CiteScore tell a broadly similar story. Both will rank Nature, The Lancet, and Cell at the top of their respective fields. For the most active and widely cited journals, the two metrics produce broadly consistent relative rankings within subject categories. 

 If a journal ranks Q1 in both JIF and CiteScore for its subject category, you have strong independent confirmation from two different databases that it is a top-tier journal. 

Where They Diverge — and Why 

1. The Citation Window Difference 

CiteScore uses a 4-year citation window versus JIF’s 2-year window. This produces meaningful differences in fields where citation cycles are slow: 

•  Journals in mathematics, social sciences, ecology, and engineering typically have higher CiteScore relative to JIF because the 4-year window captures more of their citations 
• Journals in fast-moving biomedical fields show less difference between the two metrics because most citations occur within the first two years regardless 

The practical implication: for slow-citation fields, CiteScore is often a more accurate reflection of a journal’s true influence. For fast-citation biomedical fields, both metrics are broadly comparable.

2. Document Types in the Denominator 

JIF counts only original research articles and reviews in its denominator. CiteScore counts all document types — editorials, letters, corrections, meeting abstracts, and everything else. 

 This creates predictable divergence for journals that publish significant volumes of non-research content: 

•  A journal publishing many widely cited editorials will have a higher JIF than CiteScore relative to its actual research output 
• A journal that publishes few editorials will have more similar JIF and CiteScore values 

CiteScore’s all-document approach is more transparent and harder to game through editorial content strategies. JIF’s approach creates the known inflation mechanism through the numerator-denominator asymmetry. 

3. Database Coverage 

Scopus indexes approximately 27,000 journals versus Web of Science’s approximately 21,000. This means: 

•  Journals indexed in Scopus but not Web of Science have a CiteScore but no official JIF 
• In fields where Scopus has better coverage (certain engineering subfields, social sciences, regional journals), CiteScore may be the only available metric 
• In fields where Web of Science coverage is stronger (some biomedical specialties), JIF is more comprehensive 

4. Typical Values 

Because CiteScore uses a 4-year window instead of 2, and includes all documents rather than just articles and reviews, CiteScore values tend to be higher than JIF values for the same journal. A journal with JIF 5 might have CiteScore 7–9. This means you cannot directly compare absolute numbers between the two metrics. 

SCImago Journal Rank (SJR): The Third Option 

It is worth briefly covering SJR as a third major free metric: 

Published by: SCImago Lab (based on Scopus data) 

Formula: Prestige-weighted citation algorithm — citations from highly-cited journals count more than citations from less-cited journals (similar to Google PageRank) 

Self-citations: Excluded 

Cost: Free at scimago.org 

SJR addresses a key weakness of both JIF and CiteScore: they treat all citations equally, whether from Nature or an obscure regional journal. SJR weights citations by the influence of the citing source. This makes it more nuanced for cross-field comparison and more resistant to gaming through coercive self-citation.

When to Use Which Metric 

Use JIF when: 

• Preparing tenure and promotion portfolios (JIF remains the dominant metric at most institutions) 
• Applying for grants where reviewers explicitly list JIF (common in NIH and national council applications) 
• Communicating your publication record to non-specialist evaluators who recognise JIF as the standard 
• Working in fast-citation biomedical fields where the 2-year window is appropriate 

 Use CiteScore when: 

• Evaluating journals indexed in Scopus but not Web of Science 
• Working in a slow-citation field (mathematics, social sciences, ecology) where the 4-year window is more meaningful 
• Comparing journals across different publishers without subscription access to JCR 
• Wanting a free, transparent metric for preliminary journal shortlisting 

 Use SJR when: 

• Comparing journals across different disciplines where you want prestige-weighted citations
• Evaluating whether a journal’s high JIF might be inflated through self-citation 
• Looking for a free alternative with broader coverage that also excludes self-citations 

 Use all three together when: 

• Making a high-stakes publication decision (e.g., which Q1 journal to target for your most important paper) 
• A journal’s metrics across different databases seem inconsistent — investigate why 
• You want the most robust possible assessment of a journal’s standing 

What Evaluators Actually Use 

Despite the broader coverage and transparency of CiteScore, JIF remains dominant in formal evaluation contexts. Research on global tenure and promotion practices consistently shows that JIF is more widely specified in institutional documentation than CiteScore. 

However, this is shifting. Many European institutions — particularly following Plan S and DORA commitments — explicitly include CiteScore alongside JIF in evaluation criteria. UK research excellence frameworks and several major funding bodies now accept CiteScore as an equivalent metric. 

If you are preparing a grant application or tenure package and are unsure which metric to use, include both with clear labelling. Presenting multiple consistent metrics (e.g., “IF 8.4 [JCR 2024], CiteScore 11.2 [Scopus 2024], Q1 in both”) is more compelling than either metric alone. 

Practical Decision Guide: Which to Quote in Which Context 

Context	Use JIF	Use CiteScore	Use Both
Tenure/promotion portfolio	Primary	Secondary or omit	If institution accepts both
NIH grant application	Yes	Secondary	If space allows
Journal shortlisting	Check	Primary (free)	Best approach
Evaluating a new journal	Verify	Primary check	Yes
Cross-field comparison	Avoid	Avoid (use SNIP)	Use SNIP instead
Slow-citation field	Use 5-year IF	Preferred	Both for completeness

 

How to Read a Journal’s Metrics Page 

Most journals display their metric data on a dedicated “Journal Metrics,” “About,” or “For Authors” page. Knowing what to look for — and what is missing — tells you as much as the numbers themselves. 

 What a reputable journal’s metrics page includes 

• Current and historical JIF (with the year clearly labelled) 
• JCR subject category and quartile ranking 
• CiteScore from Scopus (often with a link to the Scopus journal page) 
• Acceptance rate or submission volume statistics 
• Time to first decision and time to publication averages 

What to check when metrics look suspicious 

IF from an unofficial source: If the “Impact Factor” displayed links to Index Copernicus, Global Impact Factor, or any source other than Clarivate’s JCR, it is not an official IF. Search the journal at mjl.clarivate.com. 

No Scopus listing: If a journal displays an IF but has no CiteScore and no Scopus page, check whether it is actually indexed. Many predatory journals claim metrics they cannot legitimately have. 

Very high IF relative to field: A newly launched journal in a slow-citation field claiming an IF of 8 in its first three years of existence is impossible — JCR does not assign IFs until a journal has been indexed for two full citation years, and reaching a high IF in a slow-citation field takes sustained performance over years. 

CiteScore vs Impact Factor: Which Gets Higher Numbers? 

Because CiteScore uses a 4-year citation window and counts all document types in both numerator and denominator, its absolute values tend to be higher than JIF for the same journal. The ratio is not fixed, but as an approximate guide: 

IF range	Typical CiteScore range
Below 1	0.5–2
1–3	1.5–5
3–7	5–11
7–15	10–22
Above 15	20+

 

This means you cannot directly compare a journal’s IF to another journal’s CiteScore — only IF-to-IF and CiteScore-to-CiteScore comparisons are valid. 

The SNIP Metric: Best for Cross-Field Comparison 

Source Normalised Impact per Paper (SNIP) is the most field-normalised of the major journal metrics. Developed by CWTS Leiden and based on Scopus data, SNIP corrects for differences in citation behaviour between fields by dividing the actual citation impact by the average citation potential for papers in that subject area.

• SNIP of 1.0 = journal performs exactly at field average 
• SNIP above 1.0 = above-average field impact 
• SNIP below 1.0 = below-average field impact 

This makes SNIP the only major metric that is genuinely comparable across fields — the metric most likely to give you a fair answer when comparing a physics journal to a biology journal. Available free via the CWTS Journal Indicators tool at journalindicators.com. 

Frequently Asked Questions 

Is impact factor or CiteScore more reliable? 

Neither is objectively more reliable — they measure the same underlying concept (citation rate per article) through different methodologies. JIF uses a 2-year window and counts only articles/reviews; CiteScore uses 4 years and counts all documents. CiteScore is more transparent and free; JIF is more universally recognised by institutions. 

Why is CiteScore usually higher than impact factor? 

Because CiteScore uses a 4-year citation window (capturing more citations) and divides by all documents rather than only articles and reviews (a larger denominator that partially offsets the numerator gain). The net effect varies by journal but CiteScore values are typically 1.5–2× the JIF for the same journal. 

Can I use CiteScore instead of impact factor in grant applications? 

It depends on the funding body’s requirements. Most major funders accept either, but many specify JIF explicitly. Check the specific grant’s author guidelines. If not specified, using both with clear labelling is the safest approach. 

Which databases cover more journals — Web of Science or Scopus? 

Scopus covers approximately 27,000 journals versus Web of Science’s approximately 21,000. Scopus has broader coverage in social sciences, engineering, and regional journals. Web of Science has stronger depth in some biomedical fields. For most comprehensive coverage, researchers check both. 

Does CiteScore include self-citations? 

Yes — CiteScore includes self-citations in both numerator and denominator. To see a metric that excludes self-citations and weights citations by source prestige, use SCImago Journal Rank (SJR) instead. 

Why is CiteScore usually higher than impact factor for the same journal? 

CiteScore uses a 4-year citation window (capturing more citations) and counts all document types rather than articles and reviews only. The net effect is typically higher absolute values for CiteScore compared to JIF for the same journal. 

Can I use CiteScore in my tenure dossier instead of impact factor? 

Generally yes — most institutions accept CiteScore as an equivalent metric to JIF. Check your institution’s specific tenure guidelines. When in doubt, present both with clear labelling. 

What is SJR and how does it differ from impact factor? 

SCImago Journal Rank (SJR) is a free metric from Elsevier based on Scopus data. Unlike JIF, SJR weights citations by the prestige of the citing journal (similar to Google PageRank) and excludes self-citations. It is available at scimago.org and is particularly useful for identifying journals whose high JIF may be partially driven by self-citation or low-prestige citation networks. 

Do all journals have both an IF and a CiteScore? 

No. A journal must be indexed in Web of Science to receive an official JIF, and in Scopus to receive a CiteScore. Many journals are indexed in one database but not the other. Some journals — particularly newer OA journals, regional journals, and humanities journals — may have neither metric, relying instead on SJR (which covers ~27,000+ Scopus-indexed journals) or domain-specific databases. 

Useful guides for researchers choosing journals

These PubScholars resources will help you evaluate and compare journals:

What is journal impact factor? – the complete foundational guide covering what JIF means, how it is used, and its limitations

How is journal impact factor calculated? – the official formula, citation windows, citable items, and three worked examples

What is a good impact factor for a journal? – field-by-field benchmarks for medicine, biology, chemistry, physics, and social sciences

Does impact factor affect manuscript acceptance chances?– what IF signals about selectivity, desk rejection rates, and submission strategy

Conclusion 

Impact factor and CiteScore measure the same underlying thing — journal citation rate — through different methodologies and from different databases. JIF remains the dominant metric in formal institutional evaluations; CiteScore offers broader coverage, a longer citation window, and free access. In practice, the most robust approach is to check both, understand why they might differ for any given journal, and present both in contexts where you want to demonstrate thoroughness. 

 Neither metric, used alone, gives a complete picture of a journal’s quality or of your publication record’s strength. The best researchers treat both as tools — useful reference points for decision-making — rather than as verdicts.