The XX Factor: Gender and Influence in Medicine

Recent studies reveal gender pay gap between male and female physicians

Aug 05, 2012 · Doximity Insider

Editor’s note: Lily Peng, M.D., Ph.D. is a Product Manager at

It hasn’t been a summer of good news for female physicians or egalitarians. A
study by Yale economists concluded that on average, "a female
primary-care physician would have been financially better off becoming a
physician assistant."
Last month, physicians from the University of
Michigan-Ann Arbor revealed that female physician researchers earn $13,339
less in salary
, on average, than male counterparts doing the same work,
after adjustments.

If how much one earns is a proxy for value, then these studies could indicate
that female physicians are less-valued members of the medical community --- a
thought even more concerning than the atrocious income gap. Clearly, there is
more to discerning worth in the service field known for its Hippocratic Oath.
Are there proxies beyond payment that can help measure how much professional
influence women hold in the medical community? To shed some light on this
question, we turned to the database powering Doximity’s physician network. We
examined over 1.3 million colleague invitations exchanged over the past 2
years: a physician-to-physician outreach that reflects real-world professional
relationships, respect and trust. To keep the analysis simple, we focused on
the five largest specialties --- Family Medicine, Internal Medicine,
Pediatrics, Obstetrics & Gynecology, and Surgery.

We then measured the level of female influence via a formula we named XX
factor. A high XX factor meant that female physicians were receiving a
disproportionately higher number of colleague requests than would be expected
based on their gender ratio within that specialty. For instance, of surgeons
graduating medical school in 1970: if 20% were female, it would be predicted
that these women would receive 20% of colleague request volume and men the
remaining 80% of colleague invitations.

We then plotted the XX factor against the gender ratio (% female) for each
specialty by graduation decade. What we found was rather surprising. If female
physicians were valued less than male physicians by the medical community, one
would expect that the XX factor to be low. However, the XX factor never dipped
below for the no-preference zone for any graduation year. Furthermore, given
that in general, the pay gap between men and women tends to increase by
, one would expect that the XX factor would be lowest in older
generations of physicians. Yet, when we looked at physicians graduating in the
1960s and 1970s, we found females received disproportionately higher rates of
colleague requests. In fact, female surgeons who graduated in the 1970s
received colleague requests at a rate that was 50% higher than expected. Those
that graduated in the 1960s saw over a whooping 200% higher rate of colleague

Vertical Axis: The XX factor = (actual % of colleague request sent to female
physicians in that specialty – predicted %) / (predicted %) Horizontal Axis:
Gender balance of that specialty.

Z-axis (video progress slider): The decade the invitation-receiving physician
graduated medical school. Of note, this is not the year physician interaction
was measured, all colleague-request interaction studied took place within the
past two years.

Circle size: Proportional to the size of the specialty.

Based on this data, it seems that though female physicians may still earn less,
they are afforded equal if not greater amount of preference in professional
outreach. Furthermore, it seems that the smaller the percentage of women in a
specialty, the stronger the XX factor, particularly for older generations of
physicians. While this data does not tell us why this is happening, it does
point to a few possible reasons. One possibility may simply be that the more
rare a group of people is, the more memorable they are. In a sea of men, it is
not hard to pick out or remember the few women. Another possibility is that
there is something special about women who choose to go into (and succeed in)
male-dominated careers. Perhaps the skills that allowed them to thrive and
overcome the challenges associated with building a career as a female physician
also make them particularly savvy networkers, or build reputations as easy to
work with. It is also likely that the effects that we observed stem from a
combination of reasons, some of which we have not even mentioned. Measuring how
much someone is valued in the community is an imperfect science with many
proxies beyond income and network behavior.

The change in gender balance over time is also well-visualized by the graph.
The number of women attending medical school is rapidly rising, and the female
ratio is in fact greater than 50% at many medical schools today. While today
roughly one-third of practicing physicians are female, already, we see
specialties like pediatrics and OB/GYN have recently tipped to majority women,
with more following. This suggests a future of equality for historically-male
specialties. In all specialties studied, the XX Factor preference for women
equalized after female percentage in a specialty grew to 10-35% of the

These encouraging results by no means indicate that women are no longer
struggling with challenges that come with being a woman in medicine. The pay
gap between men and women is very real in many professions, including medicine.
But this data does suggest that despite being behind in monetary compensation,
female physicians are well-respected and highly-valued members of the medical

Perhaps most importantly, we’re seeing the spotlight focus brighter on this
gender gap. The results of the financial compensation studies have been
amplified across the internet thanks to journalists from The Atlantic and
The New York Times, and momentum continues to build from recent nationwide
efforts such as Rock Health’s XX in Health Week and the BlogHer
conference’s HealthMinder Day. Let’s keep it going.

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