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Research impact measures

Bibliometrics is a field of study that uses quantitative analysis to evaluate scientific publications, authors, and their impact. It involves measuring and analyzing various aspects of publications, including citation patterns, the number of publications, the number of authors, and the quality of the journals in which they appear.

Numeric measures provide an indication of a researcher’s impact. These measures are based on the assumption that influential researchers and important works are cited most frequently.

Bibliometrics outputs include:

  • Number of publications
  • Number of cited publications
  • Number of times a publication has been cited
  • H-index
  • Journal Impact Factors

Bibliometrics should not be used as the sole measure of research quality. They should be used in conjunction with other evaluation methods, such as expert review, to provide a comprehensive and accurate assessment of quality and impact.

Journal rankings are a system for evaluating the relative quality or prestige of academic journals within a particular field or discipline. These rankings are used by researchers, institutions, and funding agencies to make decisions about where to publish research or allocate resources. 

It is important to note that journal rankings are not perfect measures of journal quality, and they have been subject to criticism for various reasons including self-citation practices, the prestige of the publisher, or biases against non-English language journals or interdisciplinary research. Additionally, rankings should not be the sole factor used to evaluate the quality or impact of research. It is important to consider other factors, such as the rigour of the peer-review process, the relevance of the research, and its potential impact on society.


Web of Science - Journal Citation Reports (JCR) - JIF

JCR - Journal Citation Reports TM uses Web of Science publications data to produce a JIF (Journal Impact Factor TM). The Impact Factor is the average number of citations to papers in a journal in one year, from articles published in any Thomson Reuters listed journal during the previous two years.

Note: the JCR impact factor should not be the only tool used by researchers to assess the usefulness of a journal. It is recommended that it be used together with informed peer review. Other measures in the JCR include:

Eigenfactor™ Score

An Eigenfactor Score is the number of current year citations to citable items from the previous five years, similar to the page rank algorithm used by Google

Article Influence™ Score

The Article Influence™ Score determines the average influence of a journal's articles over the first five years after publication, calculated as the journal's Eigenfactor Score divided by the number of articles published by the journal.


Scopus - CiteScore and SJR

CiteScore, SCImago Journal Rank (SJR), and Source Normalized Impact per Paper (SNIP) are the metrics tools available to measure data through the Scopus database. This enables journals from disciplines with different citation behaviours (number and frequency of citations) to be compared.

Scopus calculates the number of citations over a four-year period, divided by the number of publications to produce a CiteScore (Scopus, CiteScore 2020).

SCImago Journal Ranking (SJR) uses Scopus publications data to weight citations from prestigious journals (similar to a Google page ranking algorithm) to calculate a ranking for journals (SCImago, 2021).

Other measures you could use as an indication of your research impact include:

  • Article download count:
    Download counts are provided by some publication databases and other web platforms, although there is no standard way to aggregate counts from different systems. Examples of platforms that provide download counts include:
  • ResearchOnline@ND
  • Public Library of Science (in the metrics tab for individual articles)
  • Number of media appearances
  • Community engagement activities
  • Number of book reviews by experts within the same field
  • Number of publisher book sales
  • Number of libraries holding a copy of the publication
  • Citations by non-traditional sources e.g. internal government reports
  • Unpublished evidence of use of the research e.g. by community groups or NGOs

For a robust measure of research impact, use bibliometric measures in conjunction with qualitative assessment (e.g. peer review) of the content of a publication.

Use research impact measures to:

  • Record research achievement for academic promotion, grant applications and job applications
  • Benchmark performance of individuals, research groups or institutions
  • Track development of a field of research
  • Identify influential (highly cited) papers, researchers or research groups
Further reading:

When using bibliometric data, keep in mind that:

  • Each measure and tool has advantages and disadvantages
  • Citations take time to accrue
  • Citation comparisons are only meaningful if comparing like with like e.g. researchers in the same field of research and at similar career stages
  • The raw count of citations and analyses depend on database content:
    • No database lists all publications. Even the 3 main sources i.e. Web of Science, Scopus and Google Scholar vary substantially in content.
    • Journals are the predominant publication type in databases. Inclusion of other publications e.g. books, book chapters, conference papers and theses is improving.
    • Journal coverage in Scopus is more comprehensive than Web of Science for the Humanities and Social Sciences.
    • In Scopus, citation data only extends back to 1996 for all disciplines, so will undervalue impact of long-standing researchers.
  • Bibliometrics are best suited to the Health and Physical Science disciplines because these disciplines are dominated by international, peer-reviewed journals published in English.
  • Bibliometrics are less suited to the Social Sciences and Humanities because researchers in these fields often publish in books and conference papers which are less likely to have citation counts. If the source does have citation counts, they are likely to be lower because readership is more limited, there are fewer researchers in these disciplines, research often has a local focus and may be published in a local (non-English) language.