Skip to Content
Citation counts are the number of citations of:
These counts vary according to how each database does the measuring.
The publication output is the number of publications produced by an author, a research unit, an institution, or a journal.
It may comprise a list of publications, or just a total number.
The h-index measures a researcher's standing by combining productivity and citation counts. It is generally seen as a measure of the researcher's entire career impact and tends to favour researchers who have published a larger number of papers. A higher h-index implies greater impact.
A researcher or journal with an h-index of x has published x articles, each of which has been cited at least x times. For example, a researcher has an h-index of 10 if 10 of their published articles have each been cited at least 10 times. The author has probably published more than 10 articles, but for the h-index to increase to 11, 11 of the author's articles need to be cited 11 or more times.
The h-index is not an average of citations per article. An author with a small number of highly-cited papers may have an artificially high number of average citations. Their h-index reflects the fact that they have published few papers.
Variations on the h-index exist. For example, the h5-index is the h-index for articles published in the last 5 complete years, which might be a fairer measure for new and emerging researchers.
The h-index is used to compare researchers' or journals' publication impact, but only within the same discipline, as publishing and citation practices differ among disciplines.
Page authorised by University Librarian
Last updated on Monday 17 September 2018