h-index explained
The h-index is a statistic designed to account for both the productivity and the impact of a scholar.
"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," where Np is "the number of papers published over n years" (Hirsch, 2005).
The index h indicates that a researcher has published h articles that have been cited h or more times.
Reference:
Hirsch, J. E. (2005). An Index to Quantify an Individual’s Scientific Research Output. Proceedings of the National Academy of Sciences of the United States of America, 102(46), 16569–16572. doi:10.2307/4152261
Calculating h-index
To calculate the h-index, the scholar’s or journal’s articles are first ordered by the number of citations received, from most- to least-cited. Suppose a researcher has published 15 articles, cited the following number of times:
| Article | Times cited |
| 1 | 115 |
| 2 | 20 |
| 3 | 18 |
| 4 | 12 |
| 5 | 7 |
| 6 | 7 |
| 7 | 4 |
| 8 | 4 |
| 9 | 4 |
| 10 | 3 |
| 11 | 2 |
| 12 | 2 |
| 13 | 1 |
| 14 | 0 |
| 15 | 0 |
This researcher has an h-index of 6, because six of his or her articles have received six or more citations, while the remaining nine have received fewer than six citations. Note that the mean number of citations received is considerably higher, 13.3, because of the effect of the one exceptionally influential article. The h-index is designed to reduce the weight of a small number of highly cited papers.
Finding h-index: Web of Science
- Go to Web of Science
- Change database selection to Web of Science Core Collection using the drop-down menu at the top of the page
- Change search type to Author Search using the drop down menu above the search bar. Your search screen will look like this:
- Complete the search form. Enter the name (and name variants, if applicable), research domain, and organization(s) of the author.
- Your search may return results from multiple authors. Web of Science tries to group these into author record sets. These sets are linked at the top of your search results. Click to view the record sets and select only the ones that fit your author.
- When you are satisfied that your results list is accurate for the target author, next decide what types of publications to include. Click Document Types at the left to expand the list of options. The most conservative approach is to include feature articles and reviews while excluding other options, such as editorial materials, book reviews, meeting abstracts, etc.
- When you have finalized the list of publications, click Create Citation Report at the upper right
- Summary statistics are provided at the upper right, including h-index.
- For more details, the articles are listed by descending number of citations received. A horizontal orange line between two items indicates the h-index: the number of items above that line is equal to the h-index value.
- If you want to view citation statistics for a selection of the author's articles but not the full results list (e.g., articles written since tenure, sole-author papers, etc.), return to the list of search results. Check the boxes next to the articles you want to include. At the top of the page, click the Add the selected records to your marked list icon (a box with a check mark and a plus sign). Click the number next to that icon to view your marked list. Click Create Citation Report to see the citation statistics for this selection of articles.
Finding h-index: Google Scholar
To find your h-index using Google Scholar, you will first need to create a Google Scholar profile.
Your profile page will display your total citations, h-index, and i10-index, both total and for the last five years.
