skip to content

On this page:


What are bibliometrics?

Here is the Wikipedia definition of bibliometrics and links to individual entries on various types of bibliometrics.

The Metrics Tookit provides excellent guidance for demonstrating and evaluating claims of research impact: you can quickly understand what a metric means, how it is calculated, and if it’s good match for your impact question.


How might researchers use bibliometrics?

  • Deciding where to publish

  • Assessing papers

  • Demonstrate the value of their research to funders

  • Use on their online profile or CV

  • Deciding who to collaborate with


Impact Factor (IF)

  • How often papers in a journal are cited on average over the preceding 2 years

  • Measures the rank or importance of a journal

  • The higher the number, the ‘better’ the journal e.g. Nature IF is 41.456, Angewandte Chemie IF is 11.261, Liquid Crystals IF is 2.486

  • Found on the journal website or the JCR (Journal Citation Reports) module of Web of Science, then search for a journal in the 'Go to journal profile' box on the left-hand side. The most recent impact factors will always be at least one year old because they are calculated with two years’ worth of citations.


  • Commonly used

  • Familiar

  • Influences academic practice


  • Can be manipulated

  • Self-citation

  • Editors get authors to cite their journals

  • Posted online but not actually published – lose citations

  • New journals have low scores

  • Smaller specialisms disadvantaged

This Times Higher Education article discusses whether the JIF is still credible.

There is an explanation and critique of the JIF in this PLoS article.



The h-index is the number of papers with a citation number equal to or greater than h (so an h index of 36 means the author has 36 papers with at least 36 citations).

It is found on citation databases, Google Scholar Metrics, Google Scholar Citations. On Web of Science you have to create a Citation Report.


  • Simpler process

  • Easy to use

  • Gauges career progression


  • Age bias

  • Disregards authorship position

This ImpactStory blog post critiques the h-index.


Citation analysis

This is simply a count of the number of times an article is cited by other works. Citation counts can be found on citation databases (the 'cited by' figure), and Google Scholar (see 'Cited by' figure underneath each search result), for example.


Bibliometrics - considerations

  • Beware self-citations!

  • Different databases give different results

  • Doesn’t take into account the influence outside of research

  • Seminal papers skew the results

  • Open access papers are easier to get hold of and be cited

  • Review articles often cited instead of primary research