Journal Impact Factor
Journal Impact Factor (JIF) Metric · Also known as: IF, JIF, Impact Factor, 2-year Impact Factor
Journal Impact Factor (JIF) is a metric developed by Eugene Garfield in 1955 and published annually by Clarivate Analytics through Journal Citation Reports (JCR). It measures the average citation frequency of articles published in a journal over a two-year window, serving as a proxy for journal prestige and influence. A journal's Impact Factor equals the number of citations received in year Y to articles published in Y-1 and Y-2, divided by the number of citable items published in that same window. Despite widespread adoption in research evaluation, Impact Factor has significant limitations and critics argue it conflates journal prestige with article quality.
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When to use it
Use Journal Impact Factor when: (1) selecting appropriate target journals for manuscript submissions (compare JIF within your research field); (2) evaluating journal prestige and ranking journals within a field (compare within discipline, not across disciplines); (3) assessing research quality in institutional benchmarking or hiring decisions (supplemented with article-level metrics and peer review); (4) understanding historical prestige and citation influence of a journal; (5) identifying leading journals in a field for literature review. Do NOT use Impact Factor as a proxy for individual article quality or to compare journals across different disciplines.
Strengths & limitations
- Simplicity and transparency: easy to understand and calculate; published annually with consistent methodology.
- Standardized comparison: provides single metric enabling cross-journal comparison within fields (e.g., medical journals ranked by JIF).
- Long history: Impact Factor has been calculated since 1975 (published in JCR) with historical trends available.
- Wide recognition: accepted globally in research evaluation, hiring, and promotion decisions.
- Field ranking enabled: journals ranked into quartiles (Q1–Q4) within research areas, clarifying journal tier.
- Institutional adoption: many universities integrate JIF into research evaluation and resource allocation.
- Journal vs. article quality confusion: JIF measures journal average citations, not individual article quality. High-IF journals publish low-cited articles; low-IF journals publish highly-influential articles.
- Field-dependent citation patterns: mathematics, philosophy, and humanities have low citation counts per article; biomedical research has high citation counts. A JIF of 2.0 in chemistry is high; in biology, it is low. JIF cannot fairly compare journals across disciplines.
- Two-year window bias: newer articles accumulate citations slowly. Fast-moving fields (genetics, AI) have higher citation counts in 2 years than slower-developing fields (clinical psychology). JIF disadvantages journals in slower-citation disciplines.
- Susceptible to gaming: journals can artificially inflate JIF by: (1) requiring authors to cite journal in references (mandating self-citation); (2) publishing opinion pieces and editorials that cite heavily; (3) excluding certain article types from 'citable items' denominator (inflating numerator). Clarivate attempts to detect and penalize gaming.
- Self-citation bias: does not distinguish self-citations (inflated) from external citations. Some journals boost JIF through excessive self-citation.
- Concentration in Anglophone journals: Clarivate's indexing historically favored English-language, Western journals. Non-English and regional journals underrepresented.
- Index sensitivity: JIF is sensitive to a few highly-cited articles. If one seminal review is heavily cited, average JIF rises dramatically, misrepresenting typical article impact.
Frequently asked
Why is there debate about using Impact Factor for research evaluation?
Impact Factor conflates journal prestige with article quality, which are different. A high-IF journal does not guarantee a paper is high-quality; conversely, a low-IF journal may publish groundbreaking work. Impact Factor is field-dependent (biomedics cite more than mathematics), so cross-discipline comparison is unfair. It is also susceptible to gaming (self-citation, mandated citations). Most importantly, high Impact Factor papers are often published by researchers at prestigious institutions with better resources, introducing bias into research evaluation. DORA (2012) recommends assessing individual researchers by their specific article contributions, citation impact, and peer assessment rather than journal-level metrics.
How do I find a journal's Impact Factor and what does the number mean?
Access Journal Citation Reports (JCR) through your institution's Clarivate subscription, or search clarivate.com for free impact factor data. A journal's Impact Factor is the average number of citations per article over 2 years. For example, JIF 3.5 means articles in that journal are cited an average of 3.5 times in the 2 years following publication. Higher JIF indicates greater citation impact on average, but remember this is a mean—many articles are cited fewer times, some more. Compare Impact Factor across journals within the same research field; do not compare JIF across disciplines.
Is Impact Factor the same as the number of citations my article receives?
No. Impact Factor is a journal-level metric (average for all articles in that journal over 2 years). Your article's citation count is individual and may differ substantially from the journal's Impact Factor. An article in a high-IF journal might receive few citations; an article in a low-IF journal might be highly cited. Track your individual article's citations using Google Scholar, Scopus, or Web of Science. Google Scholar updates citation counts in real-time; journal Impact Factor updates once yearly.
Can I use Impact Factor for a systematic literature review to filter articles?
Not recommended. Impact Factor ranks journals, not individual articles. Some high-IF journals publish low-quality systematic reviews; some low-IF journals publish rigorous ones. PRISMA guidelines recommend assessing each study individually for methodological quality (bias risk, study design, population, outcomes) rather than using journal Impact Factor as a proxy. Use study design filters (RCT, cohort, case-control) instead of journal prestige.
Why does my field's journals have lower Impact Factor than biomedical journals?
Impact Factor depends on citation culture. Biomedical research typically has high citation rates (researchers cite heavily due to field norms and rapid knowledge growth). Mathematics, philosophy, and engineering cite less frequently because papers address timeless problems or have narrower readership. Researchers in these fields should not be penalized for field-specific citation patterns. Use field-normalized metrics (SJR, SNIP) or compare quartile rank (Q1–Q4 within your field) rather than absolute Impact Factor values.
What is the difference between Impact Factor and CiteScore?
Impact Factor (JIF): 2-year window, calculated by Clarivate, published annually, counts only 'citable items' (articles, reviews). Typical JIF range: 0.5–10. CiteScore (Scopus): 4-year window, calculated by Elsevier/Scopus, updated daily, includes all document types. Typical CiteScore range: 0.5–10+. CiteScore values appear higher due to longer window and inclusion of more document types. Both measure journal citation impact; neither measures individual article quality. Use CiteScore within Scopus ecosystem, Impact Factor within Web of Science ecosystem. Do not directly compare JIF and CiteScore values.
Sources
- Garfield, E. (1972). Citation analysis as a tool in journal evaluation. Science, 178(4060), 471-479. DOI: 10.1126/science.178.4060.471 ↗
- Clarivate Analytics. (2023). Journal Citation Reports: Impact Factor Methodology. https://clarivate.com/webofsciencegroup/essays/journal-citation-reports-methodology/ link ↗
- San Francisco Declaration on Research Assessment. (2012). Retrieved from https://sfdora.org/ link ↗
How to cite this page
ScholarGate. (2026, June 3). Journal Impact Factor (JIF) Metric. ScholarGate. https://scholargate.app/en/bibliometrics/impact-factor
Which method?
Set this method beside its closest kin and read them side by side — the library lays the books on the table; the choice is yours.
- H-IndexBibliometrics↔ compare
- Journal Citation ReportsBibliometrics↔ compare
- SCImago Journal RankBibliometrics↔ compare
- Scopus DatabaseBibliometrics↔ compare
- Web of Science DatabaseBibliometrics↔ compare