The h-index measures an author's publications and citation counts. It indicates the number of articles (h) that have been cited at least (h) number of times. For example, an author has an h-index of 12 if she has 12 papers that have been cited at least 12 times each.
The h-index can be a great way to compare researchers in the same field. Keep in mind that different fields have different publishing practices, so comparing researchers won't always give you a complete picture.
There are other drawbacks to the h-index. Early-career researchers will often have lower h-index scores both due to the lower total number of publications and lower number of citations for newer papers. In addition, authors who self-cite can have inflated h-index scores.
Additionally, the h-index of an author may differ depending on where you find it, due to the scope of publications used in the calculation. The h-index found in Web of Science only takes into account articles indexed that database, while Google Scholar may have inflated scores due to non-scholarly citations.
In the following examples, you can see how both sources list different h-index scores for the same researcher.
On the Scopus database homepage, choose the "Authors" tab. From there, you can search an author's name. You can also click on an author's name within any article to go directly to their profile page.
From there, you can navigate to the author's profile page. The author's h-index will be listed directly below their name.
A researcher needs to have their own Google Scholar profile in order for their h-index to be listed. You can reach this page by either searching the author's name directly, or by clicking on their name in search results. The h-index will be listed in a box on the right side of the page.
Notice how the h-index varies between Scopus and Google Scholar for the same researcher.
The g-index was proposed in 2006 by Leo Egghe as an attempt to improve on the h-index. The major way the g-index differs from the h-index is that it gives more weight to highly cited articles. The g-index is not as highly used as the h-index, and it is not measured by either Google Scholar or Web of Science.
However, you can calculate an author's g-index yourself using the definition:
"[Given a set of articles] ranked in decreasing order of the number of citations that they received, the g-index is the (unique) largest number such that the top g articles received (together) at least g² citations." In other words, a g-index of 10 means that a researcher has published at least 10 articles that combined have received at least 100 citations.
How does the h-index compare to the g-index? Consider this example:
Dr. Smith has written 20 papers. Of these 20 papers, 15 of them have zero citations. The remaining five papers have 350, 35, 10, 3 and 2 citations each.
Dr. Smith would have a g-index of 20, since the top 5 (g) articles have received a total of 400 (g²) citations. Although Dr. Smith has 15 papers with no citations at all, the g-index rewards her with a higher score due to the high number of citations on a single article.
Dr. Smith would also have a h-index of 3, because she has three papers with at least three citations each. The h-index does not consider the weight of the highly cited article.
The i10-index is a measurement developed by Google and is only found in Google Scholar. It is simply the number of papers an author has that have at least 10 citations.
The i10-index is easily found in a researcher's Google Scholar profile page.
