The impact factor of a journal is a metric used as a proxy for the importance or influence of a particular journal in a field. It can be helpful in determining the what journals you might consider publishing in.

Journal impact metrics take into account the number of articles published per time period and the number of citations to articles published in that journal. They can help track citation patterns within journals and determine which journals are highly cited.

There are many factors that influence the impact of a journal and each tool may produce varying results depending on the scope of its database. Many are proprietary and only available in certain tools. 

For a more accurate picture of journal impact, use more than one tool and compare the results.

Journal Impact Factor

What is it?

The Journal Impact Factor (JIF) is a proprietary metric to Clarivate Analytics. It is a measure of the frequency with which the average article in a journal has been cited in a particular year. The calculation is typically based on a 2-year period, where a journal’s citations are divided by the total number of published citable articles. 

The JIF only applies to journals indexed in in Web of Science (owned by Clarivate Analytics). You can learn more from Clarivate's InCites Help. 

Limitations

• Although a widely recognized metric, the JIF can be influenced by the field of study, with some fields having naturally higher or lower citation rates.
• The JIF is not available for all journals and coverage varies by discipline; only calculates citations for publications indexed by Web of Science.
• Impact factors vary between disciplines and should not be used to compare journals across disciplines.
• Not an indicator for the value of individual articles or authors.
  • The impact factor was created to show the impact of a specific journal, not a specific scholar. The quality and impact of an author’s work is separate from the impact of a journal. 

Helpful Resources

• Journal Citation Reports™ Reference Guide

Source Normalized Impact per Paper (SNIP)

What is it?

The Source Normalized Impact per Paper (SNIP) is a proprietary metric offered in Scopus products and owned by Elsevier.

This metric weights citations based on the total number of citations in a given subject field, which allows you to compare journals across subjects. The impact of a single citation is given a higher value in subject areas where citations are less likely, and vice versa. SNIP is based on Scopus citation data and has a 3-year citation window.

Limitations 

• The calculation of SNIP is more complex than some other metrics, making it less accessible to the general public
• It may not be as widely used as other metrics  

Helpful Resources

• Learn more about Scopus Journal Metrics 

SCImago Journal Rank (SJR)

What is it?

SJR is a proprietary metric offered in Scopus products and owned by Elsevier. This metric is used for journals, book series and conference proceedings that weights the value of a citation based on the subject field, quality and reputation of the source. 

The SJR measures the influence of a journal, taking into account the number of citations received and the importance or prestige of the journal. The SJR normalizes for differences in citation behaviour between subject fields. With SJR, the subject field, quality, and reputation of the journal have a direct effect on the value of a citation. The measure discounts self-citations of journals where the number of such citations exceeds one-third of the total citations 

Citations are weighted – worth more or less – depending on the source they come from. The subject field, quality and reputation of the journal have a direct effect on the value of a citation.  

Limitations

• Citations from lower prestige journals get little credit 
• Ranks are based on the total number of articles, not the total number of citable articles 
• Calculations are proprietary and cannot be independently verified

Helpful Resources

• Scopus Journal Metrics 

Eigenfactor Score

What is it?

A journal's Eigenfactor score is a measure of a journal's total importance to the scientific community.

The Eigenfactor® Project was developed in 2007 by Carl Bergstrom and Jevin West from the University of Washington. It is a non-proprietary metric, but it relies on data from the Journal Citation Reports (JCR). 

The calculation is based on the number of times in the past five years, that articles from a journal have been cited in the JCR. Citations from highly ranked journals are weighted more than citations from poorly ranked journals.  

Limitations

• Difficult to compare across disciplines; journals are assigned to a single category, even if they are multidisciplinary
• The calculation is complex and less intuitive compared to the JIF 

Journal Acceptance Rate 

What is it? 

The journal acceptance rate is the percentage of manuscripts accepted for publication, compared to all manuscripts submitted. It applies to journal articles, typically in peer-reviewed publications only. Since the acceptance rate of a journal is dependant on relative demand, it can be viewed as a proxy for perceived prestige.  

Data sources for this information is often provided by the journal editor/publisher.  

Limitations 

• Can be considered an "alternative" metric 

• Many factors unrelated to quality can impact the acceptance rate; significant differences in article acceptance rates related to discipline, country affiliation of the editor, and number of reviewers per article have been found 

• Open access journals may have higher acceptance rates than subscription only journals 

Helpful Resources:  

• Check the journal website; some journals visibly post this information 

• The APA and MLA publish journal statistics that can be accessed online   

Google Scholar Journal Rankings

What is it?

Google Scholar Metrics offers journal rankings of the top 100 publications based on citations within Google Scholar for particular subject fields based on the h-index, h-core, and h-median of  articles indexed by Google Scholar that were published in the last five complete calendar years.

Limitations 

• The coverage and inclusion of indexed content included in Google Scholar is not transparent, making data difficult to verify 

Helpful Resources

• Google Scholar Metrics