A Systematic Review of Gender-Based Differences in Hirsch Index Among Academic Surgeons

The h-index is a commonly used bibliometric in academic medicine which enumerates the number of publications (h) that have been cited h times. Recent investigations have suggested that gender-based differences in h-index may exist among academic physicians. We systematically reviewed studies of academic surgeons' h-index, hypothesizing that a significant difference would exist between the h-index of men and women at all academic ranks.

Peer-reviewed journal articles authored by academic surgeons of any subspecialization in the United States between January 1, 2006, and November 20, 2017, were reviewed. We excluded studies of trainees or gender-based differences in funding without mention of h-index. Two reviewers assessed article quality using the Newcastle-Ottawa criteria. Pooled estimates of standard mean differences (SMD) in h-index between genders were calculated using random-effects meta-analyses. A subgroup analysis based on the academic rank was performed. Heterogeneity was assessed using the I² statistic. Sensitivity analyses determined the effect of study on h-index. Meta-regression identified whether surgical specialty contributed to heterogeneity.

Twelve articles comparing h-index between genders were selected from 7950. Men possessed higher h-indices than women (SMD, 0.547; P < 0.001; I² = 89.5%). Men exhibited higher h-indices at the assistant rank (SMD, 0.12; 95% confidence interval [CI], 0.01-0.24; P = 0.039) but not at the associate (SMD, 0.14; 95% CI, -0.06 to 0.33; P = 0.165) or full professor (SMD, 0.12; 95% CI, -0.08 to -0.31; P = 0.25) ranks.

The h-index is higher for men than that for women in academic surgery overall but not at individual ranks. Further investigations are necessary to address limitations in h-index and to further characterize the relationship between h-index, gender, and promotion.