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Research impact guide: H-index


The h-index qualifies the impact and quantity of an individual’s research performance.


Features of an h-index

It is a measure of the number of high impact papers a researcher has published.

The larger the number of highly cited papers, the higher the h-index, regardless of where the work was published.

It can be summed up as 'h publications with h citations each'.

For example, to have an h-index of 10, you must have at least 10 publications with at least 10 citations each.

There are three main tools to generate an h-index, including:

You can create a profile with each of these tools to save you time when locating your citation counts.

N.B.  to generate your h-index with Google Scholar, you must have a Google Scholar profile.

    Image source: Wikimedia Commons

  Issues to be aware of

  • In general, values can only be compared within a single discipline. Different citation patterns across disciplines make comparisons difficult. For example, An average medical researcher will generally have much larger h-index values than a world-class mathematician.
  • Even within a discipline, comparing h-index values is only useful if all information has been found using
    • the same database
    • the same method

               It is therefore useful to identify your h-index by its source, e.g. a 'Scopus h-index'

  • The h-index may be less useful in some disciplines, particularly the humanities and social sciences. This is because
    • publishing and citation patterns in these disciplines may mean that there are not enough citations available to generate a useful measure 
    • the publications and citations are not indexed in databases


The h-index was developed in 2005 by Professor Hirsch, a condensed matter physicist at the University of California in San Diego, to qualify the impact and quantity of an individual’s research performance.

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