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Logo of nihpaAbout Author manuscriptsSubmit a manuscriptHHS Public Access; Author Manuscript; Accepted for publication in peer reviewed journal;
Ann Surg. Author manuscript; available in PMC 2017 April 19.
Published in final edited form as:
PMCID: PMC5396390

The role of PhD faculty in advancing research in departments of surgery



To determine the academic contribution as measured by number of publications, citations, and NIH funding from PhD scientists in U.S. departments of surgery.

Summary Background Data

The number of PhD faculty working in U.S. medical school clinical departments now exceeds the number working in basic science departments. The academic impact of PhDs in surgery has not been previously evaluated.


Academic metrics for 3,850 faculty at the top 55 NIH-funded university and hospital-based departments of surgery were collected using NIH RePORTER, Scopus, and departmental websites.


MD/PhDs and PhDs had significantly higher numbers of publications and citations than MDs, regardless of academic or institutional rank. PhDs had the greatest proportion of NIH funding compared to both MDs and MD/PhDs. Across all academic ranks, 50.2% of PhDs had received NIH funding compared to 15.2% of MDs and 33.9% of MD/PhDs (p<0.001). The proportion of PhDs with NIH funding in the top 10 departments did not differ from those working in departments ranked 11–50 (p=0.456). A greater percentage of departmental PhD faculty was associated with increased rates of MD funding.


The presence of dedicated research faculty with PhDs supports the academic mission of surgery departments by increasing both NIH funding and scholarly productivity. In contrast to MDs and MD/PhDs, PhDs appear to have similar levels of academic output and funding independent of the overall NIH funding environment of their department. This suggests that research programs in departments with limited resources may be enhanced by the recruitment of PhD faculty.


The number of PhD faculty working in U.S. medical schools has been increasing for nearly four decades.1 Currently, the number of PhDs employed by clinical departments is nearly 40% higher than those employed by basic science departments.2 This trend is thought to be the result of several factors including increasing pressure on MD faculty to generate clinical revenue, growing emphasis placed on translational research by funding agencies, and greater technological specialization and training required to conduct cutting-edge research.35 As a result of these changes, medical schools have seemingly adapted by hiring more dedicated research faculty with PhDs to help carry out and diversify their academic mission.

Departments of surgery have perhaps experienced even greater strain on their research enterprise compared to other departments, as academic medical centers rely heavily on surgeons to provide a major source of revenue.6 Academic surgeons face considerable time constraints due to the high number of hours spent providing patient care relative to other medical specialties.7 A possible side effect of this is a lag in research productivity compared to other clinical departments. A survey of members of the Society of University Surgeons found that only 46% reported that they were active researchers.8 Additionally, studies have also shown that surgical NIH grant submissions are less likely to be funded than nonsurgical submissions, and when funded, receive smaller award amounts.9,10 A proposed strategy for departments to overcome surgeons’ limitations in conducting research is to increase the number of PhD faculty who have both advanced training and time devoted to surgical research.3

In 2014, 4.1% of PhD faculty working in U.S. medical schools had appointments in departments of surgery.2 The objective of this study was to examine differences in the number of publications, citations, and NIH funding between faculty with MDs, MD/PhDs, and PhDs in U.S. departments of surgery. A secondary aim is to compare the performance of PhDs working in top 10 NIH funded departments of surgery compared to departments receiving less NIH funding (ranked 11–55). Lastly, we examined academic performance of MD faculty as a function of the percentage of PhDs working within their department.


Data Source

Our study sample included faculty working in the top 50 U.S. university-based departments of surgery with the highest amounts of NIH funding according to the Blue Ridge Institute for Medical Research.11 Our sample also included 5 additional NIH funded hospital-based departments of surgery that were associated with, but separate, from a medical school. In total, 55 departments of surgery were included in our sample. Departmental websites were used to generate a list of faculty members working at these institutions. A total of 3,850 surgical faculty were identified and information on academic rank, division, and titles were collected from departmental websites as well. Additional data on the number of publications, citations, and H index for each faculty member was obtained from Elsevier’s SCOPUS bibliographic database ( History of NIH funding for each faculty member was collected using the NIH online data repository of funding, NIH RePORT ( and checked using Grantome online database ( Binary variables were created to categorize whether or not faculty had any type of NIH funding and whether or not faculty had received funding through specific mechanisms such as K awards, R21, R01, P01, and U01. Data collection occurred between September 1, 2014 and January 31, 2015. Additional information on how the surgical faculty database used in the study was developed has been previously published.12


The objective of this study was to examine differences in the number of publications, citations, and NIH funding between faculty with MDs, MD/PhDs, and PhDs in U.S. departments of surgery. Descriptive statistics on the number of MDs, MD/PhDs, and PhDs at each academic rank (instructor, assistant, associate, and professor), departmental division, and institutional funding rank (top 10 NIH funded institution vs. institutions ranked 11–55) are reported.

The three primary outcomes of interest in this study were compared between MD, MD/PhD, and PhD faculty at the same academic rank in order to control for career stage. For example, the number of publications for a PhD faculty member at the assistant professor rank was only compared to assistant professors with MDs and MD/PhDs. Additionally, departments were ranked and grouped into quintiles according to the percentage of departmental faculty with PhDs in order to compare the academic performance of MD faculty across PhD percentage quintiles. Continuous outcome variables were evaluated using one-way ANOVA and independent samples T tests. Categorical outcome variables were analyzed using chi square and Fisher’s exact tests. All tests were two-tailed and alpha was set at 0.05.


In our study sample, we found that the greatest percentage of PhDs were working in divisions of research (30.5%), general surgery (19.3%), cardiothoracic (9.9%), oncology (8.5%), and transplant (7.6%). Divisions with the lowest percentage of PhDs were vascular (1.7%), acute care surgery (2.4%), pediatric surgery (2.5%), and plastic surgery (4.0%). Most MD/PhDs were working in divisions of general surgery (21.2%), transplant (17.3%), cardiothoracic (14.5%), and oncology (12.3%). Divisions with the lowest percentage of MD/PhDs were ENT (0.6%), urology (0.6%), trauma/critical care (2.2%), acute care surgery (2.2%), and vascular (4.5%). Among PhD faculty, the most common academic rank was assistant professor (28.1%), followed by associate professor (26.2%), full professor (24.0%), and instructor (21.7%). In contrast, the most common academic rank for both MDs and MD/PhDs was full professor (32.6% and 42.5%, respectively). Over 40% of PhDs and 37.5% of MD/PhDs were working in top 10 NIH-funded departments. (Table 1)

Table 1
Characteristics of academic faculty in the top 55 Departments of Surgery

At the instructor, assistant, and associate ranks, PhDs had a significantly greater number of publications, citations, and H indexes than MDs. (Table 2) There were no differences between the number of publications or citations of PhD and MDs at the professor rank (p=1.000 and 0.897). PhDs and MD/PhDs did not significantly differ in their number of publications or citations at any rank, with the exception of assistant professor, where MD/PhDs had an average of 16.6 more publications than PhDs (p=0.049). (Table 3)

Table 2
Scholarly output by degree type and academic rank
Table 3
Mean differences in publications and citations between PhDs and other faculty

PhDs had a significantly higher percentage of NIH funded researchers at each academic rank (79.2% professor, 62.1% associate, 33.9% assistant, 25.0% instructor) compared to both MDs and MD/PhDs. MD/PhDs were significantly more likely than other faculty to have received a K award, whereas significantly more PhDs had received funding through R21, R01, P01, and U01 funding mechanisms than MD and MD/PhD faculty. (Table 4)

Table 4
Percentage of faculty with NIH funding by degree type and academic rank

When comparing the number of publications and citations between PhD faculty working in a top 10 NIH funded institution and PhD faculty working in institutions ranked 11–55, we found no significant differences. There was also not a significant difference between percentages of PhD faculty with NIH funding in top 10 departments and departments ranked 11–50. (Table 5)

Table 5
Comparison of academic productivity between faculty at top 10 NIH-funded departments and those at departments ranked 11–55

There were significant differences in the percentage of MD faculty receiving NIH funding across departmental PhD quintiles. Overall, the rates of MD NIH funding were highest in departments with the largest percentage of PhD faculty (p<0.001). Specifically, R01 grants were more commonly awarded to MDs in departments that belonged to the highest PhD percentage quintile (p=0.003). The mean number of publications by MD faculty did not significantly differ across quintiles (p=0.488) (Table 6)

Table 6
Percentage of MD Faculty with NIH funding Across Departmental PhD Percentage Quintiles


Overall we found that PhDs were most likely to work in divisions of research in surgery departments. Also, a large percentage of both MD/PhDs and PhDs worked in general surgery, cardiothoracic, oncology, and transplant surgery divisions. Vascular, plastic, and trauma/critical care surgery divisions tended to have fewer MD/PhDs and PhDs than other divisions. Our results demonstrated that MD/PhD and PhD faculty working in departments of surgery published significantly more than their MD counterparts at the same academic rank. Additionally, a significantly higher percentage of PhDs had received NIH funding than MDs and MD/PhDs. When comparing PhDs working in the top 10 departments of surgery versus those working in departments ranked 11–55, we found no significant differences in their academic performance. Lastly, the number of MDs with R01 grants was significantly higher in departments with a greater percentage of PhD faculty.

To date, few studies have examined the academic performance of PhDs in clinical departments, despite the fact that more PhD faculty are now working in these departments than basic science departments. Our results are similar to other national studies that have examined publication rates among anesthesiology faculty, which have found that MDs were 73% less likely to publish in a two year period than PhDs and 55% less likely to publish than MD/PhDs.13 Furthermore, this study also reported that for each additional MD/PhD or PhD faculty member added to a department, a corresponding increase of 1–2 publications per two year period could be expected.13 Together, these findings suggest that hiring more faculty with PhDs may be a viable strategy for departments of surgery interested in increasing their academic output. This is likely due to the fact that these faculty members may not only have more dedicated time for research, but they are also in many instances bringing a complementary skill set for conducting research due to advanced training and prior research experience in non-surgical scientific and medical fields. Furthermore, specifically investing in hiring PhDs may be more cost-effective for departments than allotting more dedicated research time to MD faculty, who are needed to generate clinical revenue and typically have higher salaries.14

In addition to increasing academic output and funding, there are several other potential benefits of appointing PhD faculty in surgical departments. One example is that they may facilitate interdisciplinary collaboration through joint appointments in other departments, which can be critical for efficiently carrying out translational research.4 Translational research requires interdisciplinary teams and it is often difficult for surgeons to obtain funding independently without collaborating.9 Our results that MDs working in departments with a greater percentage of PhDs are more likely to have NIH funding, and, specifically, R01 funding corroborate these previous findings. Improved access to cross-disciplinary collaborations may provide additional resources and expertise, such as specialized equipment or postdoctoral fellows, which may make conducting large-scale research studies more feasible for clinicians.

Some evidence suggests that MD/PhDs may have more barriers to participating in collaborative research than PhDs do. A national survey of chairs of surgery at U.S. medical schools found that only 27.2% of MD/PhDs collaborated outside their departments whereas 80.8% of PhDs did.4 Furthermore, the same study showed that surgeons are less likely to participate in institution-wide efforts than departmental activities.4 This may indicate that surgeons’ require closer proximity to their collaborators than other clinician researchers. Barriers to collaboration such as organizational silos and limited communication are reduced when researchers and clinicians reside within the same department. Employing PhD researchers in the same department provides surgeons with ready access to researchers interested in the surgical applications of their research. Additionally, the presence of PhDs in departments of surgery may help clinician-researchers by serving as research mentors who can offer expertise even on projects they are not directly involved in. This may be especially important for divisions that have low numbers of clinician-scientists, such as trauma/critical care and vascular surgery.

Another unique finding of our study was that the academic output and funding history of PhD faculty did not differ between the top 10 departments with the highest amount of funding and departments ranked 11–55. This suggests that departments with fewer financial resources to dedicate towards research may especially benefit from PhD researchers who are able to sustain academic productivity and obtain NIH funding in lower resource settings. Given the current funding environment, surgeon-scientists often need to commit a greater percentage of their time to research, which is costly, or collaborate as part interdisciplinary group to successfully compete for grants in the larger research community.9 Hiring PhDs within surgery departments provides built-in access to collaborators who have dedicated time to pursue the academic research mission.

Finally, it is important to note that surgeons at modern academic medical centers are facing increased clinical pressure to produce RVUs. Growing clinical demands limit the amount of time surgeons can dedicate to the research mission, which, although important, may be secondary to providing surgical care for patients. By providing dedicated support for research activities, PhDs may be able to extend the academic mission of surgery departments while allowing clinicians to focus more on patient care.


This study has several limitations due to its data sources and retrospective design. Departmental websites were used to identify faculty included in the study and these sites may not have been up to date or provided complete information on all faculty employed by the department. Other important data such as percent effort dedicated to research versus clinical and teaching activities, which may account for differences in research productivity, were not available in our sources. Additionally, it is possible that departments employed many PhDs identified in our cohort as non-independent faculty members. Nationally, medical schools have been employing fewer PhDs as tenure-track faculty.15 As a result, our study of surgical faculty may be biased by the fact that the PhD faculty working in these departments may have been higher performing researchers who were able to compete successfully for a faculty position. Therefore, our study only captures the impact of PhDs on faculty in departments and not those working as staff. Finally, the only funding source for grants our study considered was NIH funding. It is likely that faculty in our dataset also obtained funding from other sources such as the Department of Defense or other grant-making foundations. Unfortunately, information on these types of grant is not publicly reported so we were unable to incorporate it into our study.

Another limitation of our study is due to its cross-sectional design. Although we found that a larger percentage of PhDs worked in top 10 NIH-funded departments, we do not know whether the presence of PhDs increased the national ranking of these institutions or whether more PhDs were hired due to the better financial environment of these departments. We also cannot determine whether or not hiring more PhDs leads to increased collaboration between researchers and clinicians and whether this results in higher numbers of departmental publications.

Lastly, our study only compared differences between faculty with terminal degrees. We do not know the impact of having a master’s level degree on MD productivity. For example, our study was not able to compare the performance of MDs with other MDs that have an additional master’s degree such as an MPH. It is possible that master’s degrees may mitigate the disparity in academic productivity between MDs and PhDs by providing MDs with more experience and training in research methodology.


Independent of rank and institution, faculty with PhDs had significantly more publications, citations, and NIH funding than faculty with MDs. Investing in PhD faculty with focused research commitments may help surgery departments increase academic output and NIH funding. Furthermore, the presence of faculty with dedicated research training within surgical departments may yield greater advancements in scientific knowledge through interdisciplinary and translational research collaborations. Ultimately, patient care is improved through research and departments of surgery must find new ways to advance this central mission.


Authors were supported in part by grants from the NIH to LGK (R01 GM092758) and TAZ (R01 CA122596 and R01 CA194593).


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