The income gap between men and women in the United States has been closing over the last quarter century, but not among physicians.
The earnings of male physicians exceed those of female physicians by 25 percent, a trend that has held steady from 1987 to 2010, according to a study published Sept. 2 in JAMA Internal Medicine.
Over those same years, the male-female earnings gap in the general population closed from 28 to 15 percent, the researchers found.
Meanwhile, the percentage of female physicians rose from 10 percent to 28 percent, and women now make up about half of medical school graduates.
"Given that in the overall economy women have now closed more than half the gender income gap that was present in the late 1980s and given that many more physicians are now women, we were surprised to find such persistent income disparity between men and women in medicine," said study author Anupam Jena, assistant professor of health care policy and medicine at Harvard Medical School and general internist at Massachusetts General Hospital.
The study, conducted with collaborators at the University of Southern California and Harvard Kennedy School, was based on nationally representative data from the Current Population Survey (CPS), which is collected by the U.S. Census Bureau and the U.S. Bureau of Labor Statistics.
The study compared trends in male and female physician earnings with earnings of other health care professionals and with the general population over three periods from 1987 to 2010. The researchers corrected for the number of hours worked and adjusted all of the figures to 2010 dollar amounts.
There are several causes for the disparity in pay, the researchers said.
One is that women are more likely than men to choose specialties like pediatrics and family medicine that offer more patient interaction and longitudinal relationships with patients, but are often lower paying than other specialties. But it's unclear whether women chose those specialties out of personal preference, or because they face obstacles in choosing other specialties.
The CPS does not collect data about physician specialty, so this paper does not correct for differences in specialty pay. Instead of comparing male dermatologists to female dermatologists, for example, the study compares a sampling of male physicians from many specialties with a sampling of female physicians.
"Without a better understanding of the underlying causes for those choices, we can't simply conclude that just because women choose different specialties, pay disparity isn't an issue,'" Jena said.
It's possible, he noted, that in 1987 women had equal access to opportunities in medicine and that the choices that they made then—to go into specialties that are lower paid, to work fewer hours, or to join practices that pay less because of either lifestyle factors or location—are the same as the choices they're making now.
However, it is also possible that women would prefer other specialties, but that whatever barriers to opportunity that existed in 1987 have not been eliminated in a significant way.
"If women choose to work in these particular specialties because of personal preferences, that's not necessarily an issue," Jena said. "However, if women choose not to work in particular specialties because of perceived or experienced biases, or because there are few successful senior women in the fields to serve as mentors, that's a problem."
The researchers noted that, while much of the income difference between men and women in medicine may be attributed to the relative numbers of women and men in specialties with different earnings potentials, there is also evidence that even within specialties male physicians continue to be better paid than females.
For example, among physician researchers, when you look at those who have the same number of publications, the same levels of NIH funding, the same tenure status, females earn significantly less than males, Jena said.
"It is critical to understand the overall income patterns among the profession, as well as the disparity within specialties, in order to assess the efficacy of educational and professional policies that are designed to promote gender income equity," Jena said.
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