The h-index, or Hirsch index, measures the impact of a particular scientist rather than a journal. "It is defined as the highest number of publications of a scientist that received h or more citations each while the other publications have not more than h citations each (Schreiber, 2008a)." The h-index is included in Journal Citation Reports (JCR) from Web of Science. For example, a scholar with an h-index of 5 had published 5 papers, each of which has been cited by others at least 5 times.
Proposed by Egghe in 2006 to overcome a bias against highly cited papers inherent in the h-index. The g-index is the "highest number of papers of a scientist that received g or more citations, on average" (Schreiber, 2008a).
A and R Indexes
The A and R indexes are meant to be used with h and are not stand-alone indexes. The A-index is the average number of citations per "meaningful paper" (Podlubny & Kassayova, 2006). The R-index clarifies the relationship to the h-index formally (Schreiber, 2008a).