Objectives: To describe the h-index as a measure of scientific output.
Methods: The formula for this index is based on (1) the number of papers published by an author and (2) the number of citations per paper. The h-index can be used to evaluate performance by individuals or by groups of scientists working in university departments or research institutes.
Results: While the h-index is both objective and quantitative, it has some deficiencies. It does not take into account first or last author publications, numbers of coauthors, or self-citations. Numerous alternative indices have been proposed to better reflect scientists' contributions in their fields.
Conclusions: Pathologists and clinical laboratory scientists should be familiar with the h-index, as it may be used in decisions about professional advancement.