Understanding journal metrics: the Impact Factor - Author Services

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Understanding journal metrics: the Impact Factor

You can use metrics to help when you are choosing a journal to submit your work to. For a long time, citation metrics such as the Impact Factor were the standard (and only) tool available to evaluate journals and articles systematically.

What is a Journal Impact Factor?

An Impact Factor is one measure of the citations to articles published in a journal. Clarivate Analytics releases the Journal Impact Factors annually as part of the Web of Science Journal Citation Reports®. Only journals listed in the Science Citation Index Expanded® (SCIE) and Social Sciences Citation Index® (SSCI) receive an Impact Factor.

How do they calculate a journal’s Impact Factor?

This simple metric is the average number of citations to articles in a journal within a timeframe. It’s calculated in the following way:

Number of citations received in 2018 to 2016 and 2017 content
Number of articles and reviews published in 2016 and 2017

What is the 5-Year Impact Factor?

The 5-Year Impact Factor is calculated using the same method as the standard one. However, it attempts to reflect the longevity of some research by looking at the citation performance of articles published during the previous five years:

Number of citations received in 2018 to content published 2013 to 2017
Number of articles and reviews published 2013 to 2017

The 5-Year Impact Factor may be useful for assessing journals in subject areas where it takes longer for work to be cited.

What else do you need to consider?

Across disciplines, there are widely differing citation patterns, database coverage, and dominance of journals. Therefore you can see these reflected in the Impact Factors of individual journals. Differences in Impact Factor also exist between different kinds of journals (basic, applied, practitioner, or educational). Most Arts and Humanities journals will not receive an Impact Factor.

What other metrics are there?

There is a range of other metrics which measure citation performance, based either on the Web of Science or the Scopus databases. For example, these include the CiteScore, Eigenfactor, SCImago Journal Rank, and SNIP.

Once you’ve looked at citations in other scholarly articles, you can also make use of alternative metrics which measure the performance of individual articles. Look at the Altmetric attention scores and download numbers of previous articles published in journals you are considering submitting to.

Don’t know your Impact Factor from your h-index? Altmetric Attention Score from Eigenfactor? Get an introduction to research metrics with our handy guide.