Distribution of the h-index in radiation oncology conforms to a variation of power law: implications for assessing academic productivity.

Leaders of academic institutions evaluate academic productivity when deciding to hire, promote, or award resources. This study examined the distribution of the h-index, an assessment of academic standing, among radiation oncologists. The authors collected h-indices for 826 US academic radiation oncologists from a commercial bibliographic database (SCOPUS, Elsevier B.V., NL). Then, logarithmic transformation was performed on h-indices and ranked h-indices, and results were compared to estimates of a power law distribution. The h-index frequency distribution conformed to both the log-linear variation of a power law (r (2) = .99) and the beta distribution with the same fitting exponents as previously described in a power law analysis of the productivity of neurosurgeons. Within radiation oncology, as in neurosurgery, there are exceedingly more faculty with an h-index of 1-2. The distribution fitting the same variation of a power law within two fields suggests applicability to other areas of academia.