A decade of diversity: using statistical indices to compare neurosurgery to other surgical specialties

Studies have demonstrated the benefits of diversity in neurosurgery. However, recruitment of minoritized groups within the neurosurgical workforce consistently lags other surgical specialties. While racial and gender demographics of neurosurgical residents are well documented, there has been minimal exploration into the multidimensional nature of diversity. The current study will evaluate the longitudinal diversity changes in neurosurgery residency programs compared with other surgical fields with validated diversity indices.

Nationwide reports including data about resident physicians were obtained from the American Medical Association and the Association of American Medical Colleges for the academic years 2008-2021. Self-reported race, biological sex, and medical school affiliation were recorded for surgical residents in the 10 commonly recognized surgical fields. The Gini-Simpson Diversity Index was used to calculate the effective counts (ECs) of races, sexes, and medical school types for each field. A Composite Diversity Index (CDI) comprising the aforementioned diversity traits was used to calculate the percentage of characteristics upon which two randomly selected residents within each specialty would differ. CDIs were calculated for each field in every year from 2008 to 2021. Median CDIs were compared between fields using Kruskal-Wallis testing, and p values < 0.05 were deemed statistically significant.

Plastic surgery had the highest median sex EC (1.92, interquartile range [IQR] 1.78-1.95), indicating greater diversity, while neurosurgery had the third lowest sex EC (1.40, IQR 1.35-1.41). All surgical fields examined had fewer than 3 races effectively represented among their residents, despite there being 8 races present. Neurosurgery ranked among the top fields in effective racial diversity (EC 2.17, IQR 2.09-2.21) and medical school type diversity (EC 1.25, IQR 1.21-1.26). There were statistically significant differences in the sex, race, and school ECs between surgical specialties. While neurosurgery had a relatively low median overall diversity (CDI = 32.7, IQR 32.0-34.6), there was a consistent longitudinal increase in CDI from 2015 to 2021.

Neurosurgery resident physicians have become increasingly diverse in the past decade but are more homogenous than residents in other surgical fields. The continued use of diversity indices to more accurately track diversity progress over time may better inform leaders in the field of how they may best focus their equity and inclusion efforts.