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There are many citation based indicators available for evaluating journals. The most common of them will be presented in this chapter.
Other assessment tools are also available, such as the JUFO classification. Read more about journal assessment from the chapter Journals.

Responsible use

  • Indicators used to evaluate journals should not be applied when assessing individual articles or researchers.
  • Differences between fields of science must be accounted for (see chapter Differences between fields of science.)
  • See also the questions related to assessing responsibility in the chapter Indicators.

Indicators based on the number of citations and articles

Article and citation based indicators examine the average numbers of citations received within a certain period of time by publications (e.g. articles) published in the publication channel (e.g. a journal) over a certain period of time. 

IndicatorDatabaseMethod descriptionTime window
Journal Impact factor 

Journal Citation Reports

Web of Science Core Collection 

Read more information in calculating the Journal impact factor.

For example: IF 2020 = number of citations in 2020 to articles published in the journal in 2018–2019 divided by the number of articles published in the journal in 2018–2019. 

  • The number of articles does not include the editorials, interviews, opinion pieces, news and similar front matter content, but only the actual articles and review articles, i.e. citable articles.
  • The journal’s total number of citations also includes the journal’s internal citations, i.e. self-citations. However, Journal Citation Reports also publishes a journal’s IF value without the self-citations.

Citations from one year

Publications from two years


5 Year Impact Factor 

Journal Citation Reports

Web of Science Core Collection 

Read more information on calculating the 5-Year Impact Factor.

For example: 5-year IF 2020 = number of citations in 2020 to publications published in the journal in 2015–2019 divided by the total number of articles published in the journal in 2015–2019.

Citations from one year

Publications from five years

Journal Immediacy Index 

Journal Citation Reports

Web of Science Core Collection 

Read more information on calculation methods of Journal Immediacy Index.

For example: JII 2020 = number of citations in 2020 to publications published in the journal in 2020.

Citations from one year

Publications from one year

CiteScoreScopusRead more information about the CiteScore indicator.

For example: CiteScore 2015 = number of citations in 2015 divided by the number of articles published in the journal in 2012–2014.

Citations from one year

Publications from three years

Indicators based on algorithms

Algorithms are utilised for calculating Scimago and Eigenfactor indicators.

IndicatorDatabaseMethod descriptionTime windowNotes

Scimago / SJR

Scopus
  • Assesses the journal’s citation impact as a mean, article-specific value.
  • Emphasises the citations differently depending on the journal’s SJR value
  • SJR is based on Scopus’s citation materials
  • Calculation equation: https://www.scimagojr.com/files/SJR2.pdf
3 years
  • Includes articles, review articles, ‘short surveys’, conference articles.
  • Self-citations have been partly filtered out.
Eigenfactor Score

Web of Science

  • Calculating the EF is based on the PageRank algorithm, which accounts for the special characteristics of journal citation materials, especially the factor of how many citations the journals usually include.
  • Self-citations are removed.
  • Calculating the Eigenfactor: the journal’s citation impact is calculated by dividing its impact value by the number of citations in the journal.
  • Calculation equation: http://www.eigenfactor.org/methods.pdf

Citations from five years

Publications from one year

  • Eigenfactor depicts the journal’s total citation impact, not the citation impact per published article.
  • Also takes into account citations from sources other than Thomson Reuters journals, books and thesis works are also included.

Field-normalised indicators

Field-normalised indicators refer to indicators that take into account differences and special characteristics of fields of science. The methods of categorising the fields of science widely and there is no single standardised method for doing it. The use of field-normalised indicators aims to allow for comparisons of publications accross disciplines. There is more information available on field-normalising in the chapter Methodological points of view.

IndicatorDatabaseMethod descriptionTime windowNotes
Source normalized impact per paper, SNIPScopus
  • Aims to assess a journal’s citation impact within the citation context, i.e. on the basis of the characteristics of the citing publications. The disciplines are determined based on the citing articles, not on journal categories or other classifications. An individual article is given the more weighting the fewer references it has.
  • Current calculation equation (modified from the original in 2012): https://arxiv.org/abs/1209.0785 

Citations from three years, publications from one year

  • Includes research articles, conference articles and review articles
JCI (Journal Citation Indicator)Web of Science
  • JCI aims to provide a field-normalised citation impact value. The global average is 1.0.
Publications from the three previous years and citations from the year being calculated as well as the three previous years.



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