Web of Science: H-Index

The h-index attempts to take into account both an author's productivity (total number of publications) and the impact of his or her work (number of subsequent citing articles).¹ An h-index of N indicates that a researcher has published at least N papers that have each been cited at least N times. 

The h-index is typically calculated based on a researcher’s entire body of work, going back to his or her first publication. It could also be calculated for a limited number of years, or for a journal, department, research group, etc.

An h-index is found by listing all of an author's publications in descending "times cited" order. For example, take the following author's publication records:

This author has written 5 articles. 4 of them have been cited at least once, but only 3 of them have been cited 3 times or more, so the author's h-index is 3.

Anyone can calculate an h-index using information from the Web of Science or another citation database. Remember, though, that journal coverage and the completeness of citation information varies among databases. The citation data and, therefore, the h-index may vary depending on the database you use.

An author's h-index can be found in their Web of Science author profile in the "Citation Network" box. This box also contains the author's total number of publications, total number of times cited, and total citing articles. Selecting "View Citation Report" will show a more detailed citation metrics page.

H-index can be a useful metric as it reflects not only publication output, but also author impact by taking into account the number of times a set of papers is cited. However, h-index does have limitations to be aware of:

• H-indices are not comparable across disciplines. Academic disciplines vary in publication and citation frequency, so a researcher in one field may have a higher h-index than a reacher in another field simply because of publishing norms in their respective field.
• H-indices tend to favor more senior researchers. Early career researchers are typically at a disadvantage because they have fewer publications, and therefore lower h-indices.
• H-index will vary across resources that report it. Web of Science, Scopus, and Google Scholar all include different publication data, and h-index calculations are dependent on the publication data that each of these databases includes.

In light of such limitations, it's important to remember that h-index should be used with a combination of other metrics to get a more complete picture of an author’s scholarly output and impact.