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Research metrics

Learn about both journal-level metrics like impact factor as well as scholar metrics like the h-index.

What Is the H-Index?

J. E. Hirsch, a physicist at the University of California, proposed the h-index to quantify individuals' scientific research output in a 2005 PNAS paper.  The h-index measures both productivity and citation impact.

To calculate your h-index, list your papers based on the number of their citations, from most to least.  The number of citations for each paper must be equal to or greater than its rank in order to be counted.  Thus, if your first paper has at least 1 citation, your h index is at least one.  If your second paper has at least two citations, your h-index is at least two, and so on.  If you have papers A, B, C, D, and E, with 68, 12, 10, 3, and 2, respectively, your h-index is 3, because paper D (your fourth paper) must have more than four citations to be counted.

graphic representation of h-index calculation, with citations on the y axis and papers on the x axis.

Finding an H-Index with Google Scholar

1. To find a researcher's h-index with Google Scholar, search for their name.  

2. If a user profile comes up* with the correct name, discipline, and institution, click on that.

screenshot of a user profile in Google Scholar

3. The h-index will be displayed for that author under "citation indices" on the top right-hand side.

screenshot of citation indices in Google Scholar

* If no user profile comes up, you'll need to use another tool, like Web of Science (below) or manually calculate the individual's h-index.

H-Index Caveats

  • What constitutes a "high" h-index varies by discipline (physicists have higher h-indexes than librarians, generally).
  • People who have many co-authors will have a higher h-index than those who author more solo papers.
  • H-index calculators (such as Web of Science and Google Scholar) will estimate someone's h-index differently from one another because they're relying on different sources (Web of Science's database is smaller and more academic than Google Scholar's).
  • The h-index is dependent on a researcher's "academic age."  Someone who has been publishing longer will have a higher h-index relative to a newer researcher.
  • Manually calculating an h-index will likely result in a different number than automated h-indexes.

It's always best to use the h-index in context, comparing scholars with their peers, and using other metrics as well.