Skip to main content
It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
Becker Medical Library logotype
Library Quicklinks and Information

Quantifying the Impact of My Publications: What is the h index?

This libguide provides guidance on metrics and reports that can be used to quantify performance and impact based on publication data.

What is the h index?

The h index was proposed by J.E. Hirsch in 2005 and published in the Proceedings of the National Academy of Sciences of the United States of America.[i]  The h index is a quantitative metric based on analysis of publication data using publications and citations to provide “an estimate of the importance, significance, and broad impact of a scientist’s cumulative research contributions.”[ii]   According to Hirsch, the h index is defined as: “A scientist has index h if h of his or her Np papers have at least h citations each and the other (Np – h) papers have ≤h citations each.”

How Calculated: Number of papers (h) that have received at least h citations. 

As an example, an h index of 10 means that among all publications by one author, 10 of these publications have received at least 10 citations each.  

Hirsch argues that the h index is preferable to other single-number criteria, such as the total number of papers, the total number of citations and citations per paper. However, Hirsch includes several caveats:

  • A single number can never give more than a rough approximation to an individual’s multifaceted profile;
  • Other factors should be considered in combination in evaluating an individual;
  • There will be differences in typical h values in different fields, determined in part by the average number of references in a paper in the field, the average number of papers produced by each scientist in the field, and the size (number of scientists) of the field; and
  • For an author with a relatively low h that has a few seminal papers with extraordinarily high citation counts, the h index will not fully reflect that scientist’s accomplishments.[iii]
Hirsch stressed that the full career publications for an author should be used for the h index.

Since Hirsch introduced the h index in 2005, this measure of academic impact has garnered widespread interest as well as proposals for other indices based on analyses of publication data such as the g index, h (2) index, m quotient, r index, to name a few.

Several commonly used databases, such as Elsevier’s Scopus, Clarivate Analytics’ Web of Science, and Google Scholar  provide h index values for authors.


[i] Hirsch JE. An index to quantify an individual's scientific research output. Proc Natl Acad Sci U S A. 2005 November 15; 102(46): 16569–16572. doi:  10.1073/pnas.0507655102

[ii] Ibid. p. 16569.

[iii] Ibid. p. 16571

Resources to Find the h index

Understanding the h index

Do You Need an h index Report?

Do you need an h index report for yourself or a department? 

We provide h index reports (Scopus and/or Web of Science) upon request.

Contact Amy Suiter to request a report.

Strengths and Shortcomings

Strengths of the h index

  • The h index is a metric for evaluating the cumulative impact of an author’s scholarly output and performance; measures quantity with quality by comparing publications to citations.
  • The h index corrects for the disproportionate weight of highly cited publications or publications that have not yet been cited.
  • Several resources automatically calculate the h index as part of citation reports for authors.

Shortcomings of the h index

  • The h index is a metric to assess the entire body of scholarly output by an author; not intended for a specific timeframe.
  • The h index is insensitive to publications that are rarely cited such as meeting abstracts and to publications that are frequently cited such as reviews.
  • Author name variant issues and multiple versions of the same work pose challenges in establishing accurate citation data for a specific author.
  • The h index does not provide the context of the citations.
  • The h index is not considered a universal metric as it is difficult to compare authors of different seniority or disciplines. Young investigators are at a disadvantage and academic disciplines vary in the average number of publications, references and citations.
  • Self-citations or gratuitous citations among colleagues can skew the h index.
  • The h index will vary among resources depending on the publication data that is included in the calculation of the index.
  • The h index disregards author ranking and co-author characteristics on publications.
  • There are instances of “paradoxical situations” for authors who have the same number of publications, with varying citation counts, but have the same h index. As an example, Author A has eight publications which have been cited a total of 338 times and Author B also has eight publications which have been cited a total of 28 times. Author A and Author B have the same h index of 5 but Author A has a higher citation rate than Author B. See Balaban, AT. 2012. Positive and negative aspects of citation indices and journal impact factors. Scientometrics. DOI: 10.1007/s11192-102-0637-5

Is There an Alternative to the h index?: The m value

The m value is a correction of the h index for time (m = h/y). According to Hirsch,  m is an “indicator of the successfulness of a scientist” and can be used to compare scientists of different seniority. The m value can be seen as an indicator for “scientific quality” with the advantage (as compared to the h index) that the m value is corrected for career length.

How Calculated: m value = h index (h )/ number of years since first paper (n).

What are the Ranges?

Per Hirsch:

  • h index of 20 after 20 years of scientific activity, characterizes a successful scientist
  • h index of 40 after 20 years of scientific activity, characterizes outstanding scientists, likely to be found only at the top universities or major research laboratories.
  • h index of 60 after 20 years, or 90 after 30 years, characterizes truly unique individuals.
  • h index of 15-20, fellowship in the National Physical Society.
  • h index of 45 or higher, membership in the National Academy of Sciences.

Other works that discuss the h index in comparison to various medical specialties are noted here.