Impact Factors and Other Metrics

Impact Factor

SJR

Definition

Citations to a journal in the JCR year to items published in the previous two years, divided by the total number of citable items (articles and reviews) published in the journal in the previous two years.

Average number of weighted citations received in a year, by articles published in a journal in the previous 3 years.

Source

InCites Journal Citation Reports (JCR) - drawing on the data in Web of Science

Scopus

A measure of

Citation Impact

Prestige

Availability

Subscription access via JCR

Freely available via SCImago website

Journal titles

11,500+

34,000+

How is it calculated?

The number of citations of articles published in the source journal in the preceding two years divided by the number of items published in that journal in the previous two years.

Iterative process based on transfer of prestige from a journal to another, using current year citations to the source items published in that journal during the previous three years

Citations included

All document types (including editorials)

Articles, conference papers and reviews

Documents included

Articles and reviews

Articles, conference papers and reviews

Interdisciplinary comparisons

Not useful for comparing disciplines. You should only compare Impact Factors for journals in the same field.

Yes. The rank has been normalized to account for differences between the disciplines

Strengths

• Covers approximately 11,500 scholarly and technical journals and conference proceedings
• Can exclude self-citations
• Includes journals in 236 disciplines

• Assigns higher value/weight to citations form more prestigious journals
• Compensates for differences in field, type and age
• Meaningful benchmark is built in – 1 is average for a subject

Weaknesses

• Does not necessarily reflect the quality of individual articles
• Limited to journals within Web of Science
• Cannot be used to compare journals across different subject categories

• Small numbers can be off-putting to researchers
• Complicated and difficult to validate
• No idea of magnitude: how many citations does it represent?

Further Information

The Clarivate Analytics Impact Factor

About SJR