Home-field advantage: the role of selection bias in the general surgery national residency matching program

For academic general surgery residency programs, graduation from the affiliated allopathic medical school is one criterion used in resident selection. The magnitude of this criterion is unknown. The aim of this study is to describe the nature of this phenomenon, with the hypothesis that states with fewer medical schools would accept more home program graduates than states with more medical schools.

In this cross-sectional study from 2012, each allopathic medical school that participates in the American Medical College Application Service was geographically matched to its academic general surgery program that participates in the Electronic Residency Application Service. Program websites were evaluated for categorical resident rosters with medical school matriculation data. The percentage of categorical home program residents was described for each program. A 1-tailed 2-sample t-test was performed between programs in states with fewer (n≤2) medical schools and programs in states with more (n>2) medical schools, using an α = 0.05.

Of the 127 residency programs that met inclusion criteria, there were 64/127 (50.4%) programs with online categorical resident rosters and medical school graduation data. There was a mean of 26.4±12.3 included residents per residency training program. The mean program percentage of home program categorical general surgery residents was 24.6%±15.2%. The median number of medical schools per state was 2 (Interquartile Range [1-4]). A 1-tailed 2-sample t-test showed that the home program percentage rate in states with≤2 medical schools [n = 17] (30.1%±18.4%) was greater than the home program percentage rate in states with>2 medical schools [n = 47] (22.6%±13.5%) (p = 0.04).

Approximately, one-quarter of categorical general surgery slots are filled with home program graduates. States with fewer medical schools are more likely to fill general surgery slots with home program graduates than states with more medical schools. These selection criteria are important to general surgery programs and future applicants.