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Measuring research impact

What is bibliometrics?

Bibliometrics analyses the impact of research outputs using quantitative measures. Bibliometrics complements qualitative indicators of research impact such as peer review, funding received, and the number of patents and awards granted. Together they assess the quality and impact of research.

You can use bibliometrics to:

  • provide evidence of the impact of your research outputs when applying for jobs, promotion or research funding
  • find new and emerging areas of research
  • identify potential research collaborators
  • identify journals in which to publish.

Types of bibliometric measures

Here are some common bibliometric measures:

  • Citation counts: the number of times a research output appears in the reference lists of other documents (articles, books, reviews, conference proceedings etc). Found in: Google Scholar, Scopus and Web of Science.
  • H-index: designed to measure an author's productivity and impact. It is the number of an author’s publications (h) that have h or more citations to them. Found in: Google Scholar, Scopus and Web of Science.
  • Field-weighted citation impact: the ratio of citations received relative to the expected world average for the subject field, publication type and publication year. It can apply to a research output or group of research outputs. Found in SciVal.
  • Outputs in top percentiles: the number or percentage of research outputs in the top most-cited publications in the world, UK, or a specific country. Found in Scopus and SciVal.
  • Journal Impact Factor: based on the average number of citations received per paper published in that journal in the preceding two years. Found in Journal Citation Reports.
  • CiteScore: the average number of citations received in a calendar year by all items published in that journal in the proceeding three years. Found in Scopus
  • SCImago Journal Rank: places a higher value on citations from more prestigious journals. Found in Scopus
  • Scopus SNIP: a ratio of a journal's citation count per paper and the citation potential in its subject field. The Scopus SNIP normalises citation rate subject differences. Found in Scopus.

(Adapted from the Metrics Toolkit licensed under a CC-BY 4.0 licence.)

For further information about the different metrics available please visit the Metrics Toolkit.

Considerations when using bibliometrics include:

  • Quality: high citation counts may not indicate quality. For example, an article may be cited frequently because other authors are refuting its findings 
  • Disciplinary patterns: some research areas cite papers more than others. For example, in medicine and health there is a strong culture of citing and using other articles to validate findings.
  • Level of researcher experience: some metrics are higher for experienced researchers than early career researchers. It is important not to compare researchers who are at different stages of their career.
  • Database coverage: the sources used to gather publication data may index different journals. The results will vary depending on which database you use.

There are a number of techniques to help increase research visibility and impact.