The h-index

The h-index is a common indicator used for individual researchers. This measure combines the number of publications with the number of times each publication has been cited. A h-index of N means that the author has published at least N articles, of which each has been cited at least N times.

Example: If I have 5 publications that have been cited 35, 10, 7, 5 and 4 times, my h-index = 4 - I have 4 publications cited as least 4 times. If my publication with 4 citations receives 1 more, then my h-index = 5 (5 pubs cited 5 times). To get an h=6, I will need to publish a new work, and all my works must have at least 6 citations.

You can find an author’s h-index in abstract databases such as Web of Science, Google Scholar, Scopus, or Dimensions; or on author profile services attached to these databases. Many of these services use algorithms to automatically create profiles for authors in their databases. You can “claim” these profiles if you wish to control, edit and verify your own record (see Module 1).

How to: See Module 3 for guidance on how to find your h-index, and for suggestions for more informative statistics.

Issues

• The h-index is affected by field and increases with career length (e.g. McCarty & Jawitz 2013 Lenker til eit ekstern område.), so should not be compared for researchers in different fields or of different career ages.
• Your h-index may vary between sources, as different databases have different coverage of publications and citations (see module 3). In particular, finding accurate citation counts can be difficult for books, software or certain other outputs. This means that, for example, citation counts (and by extension, the h-index) for someone publishing in a book-dominated field may be an underestimate of the usage of their work. 
• What does a high h-index actually tell us? This is debated. Koltun & Hafner (2021) Lenker til eit ekstern område. found that in recent years the h-index is not correlated with awards/distinctions in biology, economics, physics or computer science.
• The h-index is based on citations, and thus will be subject to many of the same issues as citations. See next page about citations.