The meaning of the h-index

The h-index originates from the assumption that the number of citations received by a scientist is a better indicator of the relevance of his or her work than the number of papers he or she publishes or the journals where they are published. It takes into account the number of papers published and the citations to those papers in a balanced way, and thus is useful to make comparisons between scientists. The present paper addresses the most frequent questions about the h-index. Specifically, it explains its origin, its advantages compared to other indices, the factors that can influence it (e.g. age, field of knowledge, topic of research and language of publication), its variants, and the injustices it may lead to. In short, this paper provides a clear exposition of the hoped-for role of the h-index in the evaluation of scientists: that it serves as a useful complement to other indicators that are more subjective, and that it contributes to the progress of science by aiding decision-making on allocation of research resources in a more effective way, and on rewarding researchers who contribute to scientific progress in a more fair way.