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Scholarly Publication: All you need to know: Impact Factor Calculation

Summary of Impact Factor Calculation

The Web of Science Group Releases 2019 Journal Citation Reports, Revealing  the World's Most Influential Journals

The Clarivate Analytics Impact Factor

 A = total cites in 1992

B = 1992 cites to articles published in 1990-91 (this is a subset of A)

C = number of articles published in 1990-91

D = B/C = 1992 impact factor 


Using the Clarivate Analytics Impact Factor


The SNIP was created by Professor Henk Moed at CTWS, University of Leiden. It stands for Source-Normalized Impact per Paper and it measures contextual citation impact by weighting citations based on the total number of citations in a given subject field. The impact of a single citation is given a higher value in subject ares where citations are less likely, an vice versa.

SNIP (Source Normalized Impact per Paper) Calculation

journal’s citation count per paper


citation potential in its subject area

The SCImage Journal Rank (SJR)

The SCImage Journal Rank (SJR) was developed by Professor Felix de Moya and it is a prestige metric based on the idea that "all citations are not created equal". With SJR the subject field, quality and reputation of the journal has an impact on the value of a citation. A citation from a source with a relatively high SJR counts as more than a citation from a source with a lower SJR.

SJR calculation

average # of weighted citations received in a year 

# of documents published in previous 3 years


SCImago Journal Ranking is a freely available portal for ranking journals based on information in the Scopus database.  You can also obtain Country Ranking information at the portal. To access SCImago Journal Ranking, click here.

CiteScore Metrics

CiteScore metrics

CiteScore™ metrics are a new standard that help to measure journal citation impact. They are comprehensive, transparent, current and free metrics calculated using data from Scopus®, the largest abstract and citation database of peer-reviewed literature.

CiteScore metrics is a family of eight indicators that offer complementary views to analyze the publication influence of serial titles of interest:

  • CiteScore
  • CiteScore Tracker
  • CiteScore Percentile
  • CiteScore Quartiles
  • CiteScore Rank
  • Citation Count
  • Document Count
  • Percentage Cited