What is the Journal Impact Factor (JIF), and how should I use it?

Answer

What is the Journal Impact Factor?

The Journal Impact Factor (JIF) is a metric that reflects the average number of citations received in a given year by articles published in a journal during the previous two years.

It is calculated and published annually by Clarivate through the Journal Citation Reports (JCR), which uses data from the Web of Science Core Collection.
 

How is it calculated?

 

N.B. “Citable items” usually include research articles and reviews but not editorials or letters.

 

Where can I find Journal Impact Factor data?

JIF values are published annually in Clarivate’s Journal Citation Reports (JCR), which is accessible via the Library:

📍 Access:

You can:

  • Search by journal title

  • View current and historical JIFs

  • Compare JIFs across journals in the same subject category
     

What are the limitations of JIF?

Although widely known, the Journal Impact Factor has serious limitations, particularly when used to assess individual researchers or single articles:

  • ⚠️ A journal-level metric
    JIF reflects the average citation rate of a journal—not the quality or impact of any specific article.

  • ⚠️ Skewed distributions
    A small number of highly cited papers can inflate a journal’s JIF, even if most articles receive few citations.

  • ⚠️ Field bias
    JIFs vary significantly by discipline; comparisons across fields are misleading.

  • ⚠️ Vulnerability to manipulation
    Editorial policies, such as encouraging self-citation or publishing more review articles, can artificially raise JIFs.

  • ⚠️ Not suitable for evaluating individuals
    Use of JIFs in hiring, promotion, or funding decisions has been widely criticised and is discouraged by DORA, the Leiden Manifesto, and The Metric Tide.

 

When (and when not) to use Journal Impact Factor

Use with caution Avoid using for
Understanding journal reach within a specific field Assessing the quality or importance of an individual article
Comparing journals within the same subject category Evaluating researcher performance or making recruitment decisions
Supporting journal selection (alongside other factors Making funding or promotion decisions

 

📌 If you’re trying to showcase the impact of your own work, we recommend using article- or author-level metrics such as:

 

What does the University of Manchester recommend?

The University of Manchester is a signatory of the San Francisco Declaration on Research Assessment (DORA). This means:

We do not support the use of Journal Impact Factors in assessing the quality of individual researchers or research outputs.

Instead, we promote the responsible use of a range of metrics, supported by qualitative evidence of impact, as outlined in our Responsible Metrics Position Statement.

 

Need help choosing the right indicator?

If you’re unsure whether the JIF is appropriate for your purpose—or if you’d like help identifying more suitable alternatives—our team can support you.

📞 Contact the Office for Open Research

We can help with:

  • Understanding and interpreting journal metrics / indicators

  • Identifying indicators that reflect the real impact of your work

  • Supporting grant applications, promotion cases, or journal selection strategies

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  • Last Updated 23 May 2025
  • Views 7
  • Answered By John Hynes

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