Background: In academic specialties such as neurosurgery, bibliometrics are often used to guide readers, academic institutes, and researchers to make objective assessment of journals. Recently, new indices have been developed to overcome the shortcomings of the widely used Impact Factor. The objective of our study was to investigate the correlations among 6 of the commonly used bibliometric indices (Impact Factor, SCImago Journal indicator, SCOPUS h-index, Google h-index, Eigenfactor, Article Influence Score) in neurosurgical and spinal surgical journals.
Methods: A list of all neurosurgical and spinal surgical journals was compiled using the databases of SCOPUS, Clarivate Analytics (Thomson Reuters), and National Library of Medicine Catalog. Journals that are not surgically oriented, non-English journals, and nursing journals were excluded. Bivariate Spearman ranking correlation tests were performed.
Results: Fifty-four journals were included, of which 14 were spine themed. High positive correlations were obtained among the bibliometric indices of neurosurgical (nonspinal) journals (P < 0.05 in all pairs). Median values were 1.54, 0.66, 53, 25, 0.0035, and 0.46 for Impact Factor, SCImago Journal rank indicator, SCOPUS h-index, Google h-index, Eigenfactor, and Article Influence Score, respectively. However, the correlations for spinal surgical journals were more variable, likely because of the small sample size.
Conclusions: Despite the different mathematical basis among the citation-based bibliometric indices studied, they have strong correlations in ranking neurosurgical journals. This study provides evidence that the newer indices may be used interchangeably with the Impact Factor in this context, and they may, theoretically, mitigate some the shortcomings of the Impact Factor.
Keywords: Academic neurosurgery; Bibliometrics; Citations; Eigenfactor; Impact; h-index.
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