Research Impact

Learn more about quantitative metrics of journal impact produced by Journal Citation Reports (Clarivate) and Scimago Journal & Country Rank (Elsevier). The metrics listed below all use citation data to assess the impact of journals. 

Keep in mind that citation and publication patterns vary between disciplines, therefore, it important to compare journals within their disciplines.

JIF is a metric that is published in Journal Citation Reports, a database produced by the same company as Web of Science.

The JIF is calculated by dividing the number of citations in the year by the total number of articles published in the two previous years. JIFs are released annually every summer using data from the prior three years.

Variations: 

• 5 Year Impact Factor uses citation data from the previous 5 years, rather than the previous 2 years.
• Immediacy Index is the count of citations in the current year to the journal that reference content in this same year.

Be aware:

• Citation and publication patterns vary between disciplines, therefore, JIFs should only be compared within a category. For instance, the top JIFs in the field of General Internal Medicine are much higher than the top JIFs in the field of biochemistry.

A new metric that was first included in the 2021 Journal Citation Reports. This is a normalized metric, and allows for journals to be compared across disciplines. 

“In essence, the Journal Citation Indicator provides a field-normalized measure of citation impact where a value of 1.0 means that, across the journal, published papers received a number of citations equal to the average citation count in that subject category.”

Introducing the Journal Citation Indicator

The Eigenfactor Factor is found in Journal Citation Reports, as well as at The Eigenfactor Project site. The Eigenfactor score is a rating of the total importance of a scientific journal.  

Scimago Journal & Country Rank (SJR) provides metrics for journals and incorporates citation information contained in the Scopus database.

SJR is a measure of scientific influence of scholarly journals that accounts for both the number of citations received by a journal and the importance or prestige of the journals where such citations come from. SJR also provides the journal's H-Index.

Example of metrics from SJR for the New England Journal of Medicine.