Age. Experience. Specialty.
These are some of the many factors that have been used to explain why women make up about half of medical school graduates yet only 13 percent of medical school department leaders and make less than men.
But even when controlling for these factors, the pay gap persists for faculty at public medical schools, a new study finds. For a likely explanation, that leaves plain old bias.
After controlling for nine factors that drive income, researchers at Harvard Medical School and Massachusetts General Hospital found that female physicians at 24 public medical schools earned an average of $20,000 a year, or 8 percent, less than males ($227,783, compared to $247,661). Without controlling for these factors, the difference was about $50,000 a year ($206,641, compared to $257,947), the study found. It was released today in JAMA Internal Medicine.
Previous explanations for the raw difference include household responsibilities and job flexibility, but reasons for the gap among similarly productive female and male physicians are more difficult to pinpoint. In addition to discrimination, possibilities include differences in how men and women negotiate salaries and use outside job offers for leverage when negotiating, said Dr. Anupam Jena, who led the study. Jena works in Massachusetts General Hospital's Department of Medicine and in Harvard Medical School's Department of Health Care Policy.
By controlling for the factors, said Dr. Dan Blumenthal, a co-author of the study who works in the cardiology department at Massachusetts General, "I think we get much closer in trying to understand whether or not true bias exists in salary between male and female physicians at academic medical centers.”
The medical fields with the highest disparities for men and women included orthopedic surgery, obstetrics and gynecology, and cardiology. Obstetrics and gynecology was one of the fields women were most likely to enter, according to the study, but the adjusted difference between men and women was still about $36,000. Surgery has long been considered a male-dominated field, as has Blumenthal’s field of cardiology.
“If we can’t ameliorate these sex differences in compensation, we are going to have a much harder time trying to attract really qualified female physicians to go into specialties where we need them most,” Blumenthal said.
A pay gap between men and women across all professions has been widely reported. In 2015, women made 79 cents for every dollar men made, according to the Institute for Women's Policy Research. CNN reported that women won’t earn equal pay until 2059, according to the institute.
A gap between male and female doctors across a variety of institutions has also been studied—an April estimate suggested female doctors make 24 percent less—but the JAMA study’s size and specific information about factors that traditionally determine income make it unique, Blumenthal said. Jena added that using publicly available state data illustrates a way anyone can study salary differences across all fields and demographics in the future.
The study, which received funding from the National Institutes of Health, combined public employee information from 24 public medical schools on state websites with physician information from the database Doximity to get a final sample of almost 10,250 physicians. This allowed the authors to avoid using self-reported survey data, which has typically been used to analyze similar pay differences.
The researchers controlled for these factors you might expect to explain the pay gap: age, years since residency completion, faculty rank, specialty, whether physicians had received NIH funding, whether physicians had participated in clinical trials, publication count, whether physicians had graduated from one of the top 20 US News and World Report medical schools, and the amount physicians billed to Medicare in 2013.
The 24 medical schools covered 12 states, including California, Texas, and Florida. About 35 percent of the sample were women. The year 2013 was used because it was the most recent in which salary data were available. Without more specific data, the authors decided not to identify the schools.
The researchers could not control for whether physicians were full-time or part-time employees, but they analyzed pay based on gender for those who were more likely to be full-time and found that the gap persisted.
Although the differences between men and women held across institutions and regions overall, females had a statistically significant advantage in adjusted salary at two schools. Blumenthal suggested that collaboration between schools and studies driven by academic institutions and states could be used to raise awareness about the gap and offer further explanations for its persistence.
“You have to have data on who are the individuals, for where there are gaps between what they earn and what you’d expect they earn, and also their supervisors,” Jena said. “You’d have to do a deep dive there.”