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What is impact?

The impact of research is measured by citation data, social media mentions, public engagement, and the use of research in policy-making, education, and business.  

Impact is one of many factors considered in the REF when assessing the quality of research outputs.

Metrics explained

A way of measuring research impact using quantitative citation data.

  • Citation data is only one way to measure the impact of research and the fact that a publication receives citations is not always an indicator of quality
  • Controversial papers may be cited a lot and other factors such as self-citation, co-authoring, and the length of a researcher’s career can all influence the citation of their work
  • There are significant differences in citation trends across subject areas

Measures the number of times that a piece of research is mentioned on social media (e.g. tweets, mentions, shares, downloads and followers).

  • This is more immediate than traditional bibliometrics, but the academic quality of social media mentions should also be taken into consideration
  • The Scopus database provides Altmetrics information for articles where available
  • Other sources of data include Altmetric and Plum analytics which can help you track your publications

Citation counts  

The number of times an article is cited in other sources.


A measure of an individual researcher’s personal impact based on the number of times their publications are cited e.g. a h-index of four means that four of the researcher’s papers have been cited at least four times each.

Publication Count 

The number of publications published by an individual or a department.

Journal Impact Factor  

This measures the average number of citations received per paper published in that journal during the previous 2 years. For example, the 2020 impact factor for a journal would be calculated as: The number of citations in 2020 to articles published in 2018-2019 divided by the total number of articles published in that journal in 2018-2019.
Impact Factors can vary significantly across disciplines and the two year timeframe may not capture long-term impact and this method has been criticised for being susceptible to editorial manipulation.

SCImago Journal Rank (SJR)  

This metric ranks journals based on the average number of citations received per article published in that journal. It is calculated using data from the Scopus database. The calculation assigns different weightings to citations based on the prestige of the citing journal. Citations from more prestigious journals are weighted higher. It allows cross-discipline journal comparisons, but it is restricted to citations in the Scopus database.

Source-Normalized Impact per Paper (SNIP)  

This metric aims to assess a paper's citation impact relative to others in its field. It considers differences between subjects, so that impact can be compared across fields. The calculation is based on the citation count of a paper, subject field citation likelihood of being cited, and the length of the reference list of the citing papers. It has some advantages over other citation metrics, as it accounts for differences in citation practices and potentials across fields.


This uses a similar calculation to the SJR, but counts citations over a longer period , 5 years instead of 3 years. Citations received are weighted by the reputation of the citing journal. It is limited to data from the Web of Science Database.

Article Influence Score  

Aims to measure the average influence of articles published in a journal, rather than the overall influence of the journal like Eigenfactor. It is calculated by dividing a journal's Eigenfactor Score by the number of articles published by that journal. This measures the articles contribution to the overall journal influence. Limitations are that it can be skewed by a small number of highly-cited articles, and averages may not represent a typical article.

Metrics can indicate the quality and impact of research but have limitations. They can be influenced by the career stage of the author or by the discipline of the journal.

Leeds Trinity University is a signatory of the San Francisco Declaration on Research Assessment (DORA) which aims to improve evaluation of research outputs internationally.

Increase your impact

  • Publish open access to make your research available to a wider audience
  • Add your publications to Pure to make them more visible. You can also add research activities to raise your profile.
  • Use social media to connect with other researchers and promote your work
  • Get an ORCID iD, a unique identifying number, to make sure that all of your research is correctly attributed
  • Speak at conferences and do public engagement work to help to raise your profile and generate interest in your research

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