Implicit gender bias has long been suspected in many medical training programs, but until recently has been difficult to study objectively. Now, for the first time, a nationally standardized milestone evaluation system for emergency medicine residents is shining a light on these potential biases. In study published in JAMA Internal Medicine journal, researchers found that although male and female emergency medicine specialists start off residency on an equal playing field, by the end of the three–year training program male residents, on average, received higher evaluations on all 23 emergency medicine training categories – including medical knowledge, patient safety, team management, and communication.

During the first year of training, female residents actually scored slightly higher than males on 15 of the 23 areas, with notably higher scores in accountability, multitasking, and diagnosis. However, by the end of the third and final year of residency, males had gained higher scores in all 23 categories and had a 13 percent higher rate of milestone attainment per year – the equivalent of 3 to 4 months of additional training by graduation.

“We are concerned that the disparity we discovered in evaluations may point to an implicit bias,” said co–lead author Daniel O’Connor, a student in the Perelman School of Medicine at the University of Pennsylvania. “Our finding, that female residents in emergency medicine receive lower scores than males across all sub–competencies really implicates bias rather than a deficit in specific skills or knowledge.”

O’Connor and researchers from the University of Chicago Pritzker School of Medicine collected 33,456 “milestone” evaluations, from 359 emergency medicine residents over a two–year period. One–third (122) of the residents were female; two–thirds (237) were male. The training programs studied represent a mix of rural, suburban, and urban hospitals and included small, medium and large academic as well as community hospital programs.

About a third of the faculty physicians who evaluated the trainees were female (91) and two–thirds were male (194). Male and female faculty members evaluated residents similarly, consistently giving female residents lower scores throughout residency years two and three.

Although senior residents, for example, are expected to display stereotypically male characteristics such as assertiveness and independence, female residents who display such qualities may incur a penalty, even among their female role models, for violating customary gender roles.

“One way to interpret our findings is that a widening gender gap is attributable to the cumulative effects of repeated disadvantages and biases that become increasingly pronounced at the more senior levels of training,” the authors wrote.

In light of recent national discussions calling for formalized competency demonstrations before residents can graduate in their specialty, this implicit bias could have long–term implications for female physicians.

“Based on our results,” O’Connor said, “this would mean female residents could be required to complete additional training to graduate at the same level as their male counterparts.”

The National Institutes of Health, through a National Center for Advancing Translational Sciences’ Grant (UL1 TR000430), helped support this study along with a Diversity Research Grant from the University of Chicago. Usama Qadri, a medical student at the University of Chicago, also contributed to this study.