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Research Guides

Research Impact & Researcher Identity

Journal Impact

Journal impact measures the importance or influence of a particular journal in a field or discipline and can help you decide which journals you should publish 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. For a more accurate picture of journal impact, use more than one tool and compare the results.

Traditional Journal Level Metrics

Journal Impact Factor

What is it?

The Journal Impact Factor (JIF) or Impact Factor (IF) ranks journals based on how many times a journal's “average article” is cited in a particular year. The calculation is based on a 2-year citation period, where a journal’s citations are divided by the total number of published citable articles. 

The 5-Year Journal Impact Factor calculates over a larger span of years. The 5-year span can be useful for subjects where articles take longer to accumulate citations. A publication’s 5-Year Journal Impact Factor will tend to be higher than its Journal Impact Factor when the wait between publication and peak citation is greater than two years. 

Limitations

  • Open to manipulation.
    • Many scholars believe it is not the most effective way to measure a journal's impact.
  • Not all journals have a JIF.
    • Not available for all journals and coverage varies by discipline; only calculates citations for publications indexed by Web of Science.
  • Should not be used to compare journals across disciplines.
    • Impact factors vary between 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. 

Tools Available

  • Journal Citation Reports (JCR) uses citation and article count to evaluate and compare journals in a field. It can help you understand how frequently researchers are using particular journals. The resource also tracks: 
    • Total citations
    • Journal Impact Factor 
    • Eigenfactor Score
    • Most frequently cited journals, highest impact journals, and the largest journals in a field

Helpful Resources


Eigenfactor and Article Influence

What is it?

The Eigenfactor score measures the importance of a journal. The calculation is based on the number of times, in the past five years, that articles from a journal have been cited in the Journal Citation Reports (JCR). Citations from highly ranked journals are weighted more than citations from poorly ranked journals.  

The Article Influence Score measures the average influence of a journal's articles over the first five years after publication. It is calculated by dividing the Eigenfactor by the number of articles published in that journal. The mean Article Influence Score is 1.00; a score greater than 1.00 indicates that articles in a journal have above-average influence. 

Benefits

  • Takes into account the importance of each citation  
    • All citations do not hold the same weight. Eigenfactor considers if the citation is from an influential journal or a smaller publication 
  • Not influenced by self-citation 
    • Considers which journals have contributed these citations and removes journal self-citations 
  • Accounts for differences in discipline citation standards  
    • For example, Medical journals have more citations than Philosophy journals, which gives Medical journals a higher impact factor using other metrics. The Eigenfactor metric attempts to counteract these issues. 

Limitations

  • Difficult to compare across disciplines
    • Journals are assigned to a single category, even if they are multidisciplinary
  • Influenced by the sizes of the journal 
    • Score doubles in size when the journal doubles in sizes (measured as articles published per year) 

Tools Available

  • Eigenfactor: freely available database of Eigenfactor and Article Influence scores calculated by eigenfactor.org and searchable by journal name, ISSN, publisher, year and ISI category. 
  • Journal Citation Reports (JCR): uses citation and article counts to evaluate and compare journals in a field. It can help you understand how frequently researchers are using particular journals. The resource also tracks: 
    • Total citations 
    • Journal Impact Factor 
    • Eigenfactor Score 
    • Most frequently cited journals, highest impact journals, and the largest journals in a field 

CiteScore

What is it?

CiteScore is a metric for measuring journal impact in Scopus and is based on the average citations received per document. CiteScore calculates the number of citations received by a journal in one year to documents published in the three previous years, divided by the number or documents indexed in Scopus published in those same three years. It shows how highly cited the average article in a journal is relative to others in its discipline. 

CiteScore metrics are a collection of research metrics available through Scopus, including:   

  • CiteScore Percentile indicates how a journal ranks relative to other journals I the same field and can be used to compare journals in different subject fields. A CiteScore Percentile of 98% means the journal is in the top 2% of its subject field. 
  • CiteScore Tracker provides a current view of how a journal is performing during the course of the year. It is updated every month. 

Limitations

  • Cannot be used to compare journals across disciplines 
    • Differences in publication and citation behaviour in different fields affects the values 
    • Instead use a field-normalized metric such as SNIP or SJR, or use the CiteScore Percentile ranking to compare journals across disciplines using Scopus 
  • Includes citations to “non-citable” documents  
    • Journals that include these other types of material (e.g. editorials, letters, or abstracts) get a lower score relative to journals that do not 
  • Suspicion of bias 
    • Metrics developed by a scholar publishing company for use on their platform 

Tools Available

  • Scopus: provides citation tracking, visualizations, and analysis tools for journal impact and allows you to compare multiple journals across a set of metrics using the Journal Analyzer. The database also tracks: 
    • Citation tracking 
    • CiteScore 
    • SJR (SCImago Journal Rank) 
    • SNIP (Source Normalized Impact per Paper) 
  • Sources page on Scopus (freely accessible): search for journals alphabetically or by title 

Helpful Resources


SNIP (Source Normalized Impact per Paper)

What is it?

The Source Normalized Impact per Paper (SNIP) 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.

Tools Available

  • Scopus: provides citation tracking, visualizations, and analysis tools for journal impact and allows you to compare multiple journals across a set of metrics using the Journal Analyzer. The database also tracks: 
    • Citation tracking 
    • CiteScore 
    • SJR (SCImago Journal Rank) 
    • SNIP (Source Normalized Impact per Paper) 
  • Sources page on Scopus (freely accessible): search for journals alphabetically or by title 
  • CWTS Journal Indicators: provides free access to bibliometric indicators based on Scopus data 

Helpful Resources


SJR (SCImago Journal Rank)

What is it?

The SCImago Journal Rank (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 behavior between subject fields. With SJR, the subject field, quality, and reputation of the journal have a direct effect on the value of a citation. 

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.  

Benefits

  • Helps eliminate manipulation 
    • The SJR ranking is raised by being published in more reputable journals 
    • Discounts self-citations of journals where the number of such citations exceeds one-third of the total citations 

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

Tools Available

  • SCImago Journal and Country Rank: a publicly available portal for assessing and analyzing journal and country ranks. Based on Scopus citation data.  
  • Scopus: provides citation tracking, visualizations, and analysis tools for journal impact and allows you to compare multiple journals across a set of metrics using the Journal Analyzer. The database also tracks: 
    • Citation tracking 
    • CiteScore 
    • SJR (SCImago Journal Rank) 
    • SNIP (Source Normalized Impact per Paper) 
  • Sources page on Scopus (freely accessible): search for journals alphabetically or by title 

Helpful Resources


Google Scholar Metrics

What is it?

Google Scholar Metrics includes a list of the top 100 publications based on citations within Google Scholar for particular subject fields using their h5-index and h5-median. You can look at top journals in particular subject categories and sub-categories. 

The Google Scholar h5-index is the h-index for articles published in the last 5 complete years. It is the largest number h such that h articles published in 2014-2018 have at least h citations each. 

The h5-median for a publication is the median number of citations for articles that make up its h5-index. 

Helpful Resources

Altmetrics

Many scholars believe traditional metrics do not give the whole picture of research impact, especially in fields outside the sciences. Altmetrics use a range of measurements to show research impact. They measure both impact on a field or discipline and impact on society. They "expand our view of what impact looks like, but also of what’s making the impact. This matters because expressions of scholarship are becoming more diverse." 

Altmetrics can be useful for early-career researchers or new publications that need time to gain citation counts. They also account for other types of publications, such as datasets, code, or blogging.

This list is not exhaustive, and many more Altmetrics resources can be found on the Metrics Toolkit website.


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.

Limitations

  • 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
  • Higher for open access journals
    • Open access journals have statistically significantly higher acceptance rates than subscription only journals

Tools Available for Journal Acceptance Rate

This metric can be found in all products offered by Altmetric, including the free researcher bookmarklet and on many journal publisher websites and repositories (such as Figshare).


Information and definitions of metrics in this section by Metrics Toolkit. It is licensed under CC-BY 4.0