title: Part I: The application of the h-index to groups of individuals and departments in academic neurosurgery.
abstract: OBJECTIVE
  The h-index was introduced as a means of quantifying the contribution a researcher makes to the scientific literature. We evaluated the h-index for academic neurosurgeons to assess the various methods of calculation and to determine whether the h-index can be used to differentiate groups of individuals by various classifications.
  
  
  METHODS
  The h-index was calculated for all neurosurgeons from 10 institutions ranked highly by 2012 U.S. News & World Report plus the authors' institution via Scopus. The h-index also was calculated manually to evaluate its accuracy. The average h-index was calculated for groups on the basis of sex, academic rank, years in practice, institution, and subspecialty. Cumulative and mean h-indices were calculated for each department.
  
  
  RESULTS
  The median h-index for the 188 neurosurgeons was 16 (mean, 19.71; range, 0-61). There was a positive association between the h-index, academic rank, and years posttraining. There was a significant difference between the "manually calculated" and automated h-indices, particularly for more senior physicians. The difference in h-index between men and women was not statistically significant. Among subspecialties, vascular surgeons had the greatest average h-index and general neurosurgeons had the lowest. There were significant shifts in departmental rankings when the cumulative or mean departmental indices were compared with the U.S. News & World Report rankings.
  
  
  CONCLUSIONS
  Application of the h-index as a bibliometric in neurosurgery can distinguish academic productivity on the basis of academic rank, years posttraining, and neurosurgical subspecialties. The application of the h-index to compare departments is problematic and, at this time, not reliable.
authors.affiliation: College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, USA.
authors.forename: Nickalus
authors.initials: N
authors.lastname: Khan
authors.forename: Clinton J
authors.initials: CJ
authors.lastname: Thompson
authors.forename: Asim F
authors.initials: AF
authors.lastname: Choudhri
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Boop
authors.forename: Paul
authors.initials: P
authors.lastname: Klimo
mesh_terms: D000047:Academies and Institutes; D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D015706:Bibliometrics; D005180:Faculty, Medical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009493:Neurosurgery / Q000592:standards*; D010506:Periodicals as Topic; D010820:Physicians; D011643:Publishing; D012737:Sex Factors
keywords: ANOVA; Academic neurosurgery; Analysis of variance; Bibliometrics; Citations; Department; Impact; Individual; Subspecialty; h-index