A, Number of physicians engaged in each of the major professional activities.
B, Data for physicians engaged in research or teaching as their major professional
activity is shown on an expanded scale for increased clarity. Source: American
The percentage of total research project grant awards awarded to investigators
older than 50 years is shown for each degree type. For this and all other
figures, MDs include individuals with an MD degree alone plus all individuals
with an MD plus another professional degree other than PhD. Similarly, MD-PhDs
include all individuals with these 2 degrees plus any other professional degrees.
Source: National Institutes of Health (NIH).
A, Funding success rates for all investigators, regardless of experience.
B, Funding success rates for previously experienced investigators (ie, investigators
with a previously funded research project grant [RPG] award). C, Funding success
rates for investigators who have not previously been awarded an RPG are shown.
Source: National Institutes of Health (NIH).
A, Percentage of Association of American Medical Colleges (AAMC) questionnaire
respondents (surveys taken at medical school matriculation or graduation)
exhibiting an exclusive or significant interest in pursuing research as a
career activity, 1987-2003. B, Percentage of graduating respondents who exhibited
an interest in clinical or basic science teaching or research as part of their
careers, 1977-2003. Source: AAMC Matriculating and Graduating Medical Student
The total number of male and female matriculants is shown. Source: Association
of American Medical Colleges and Harvard Medical School.
Average 4-year tuition costs were obtained by adding the average costs
for each of the 4 years ending in the date shown. Source: Association of American
A, Applications by degree and year. Definitions of MDs, MD-PhDs, and
PhDs were described in the legend for Figure 2. All data were obtained by summing information from all of the
LRPs except for contraception and infertility, which was established before
2002 and which is very small compared with the new programs. New applications
refer to applicants who had not previously applied for an LRP. B, New (first-time)
applications by degree and gender. Small numbers of applicants did not specify
gender, accounting for the small difference between the total number of new
applicants shown in panel A and the data shown here. Source: Office of Loan
Repayment and Scholarship, National Institutes of Health (NIH).
A, Total cost in millions of funded K08 awards from all National Institutes
of Health (NIH) institutes, 1972-2004. B, Total numbers of K08 applications
and funded awards by year. C, Percentage of funded K08 applications by year.
A, Applications for K08 grants by degree, 1992-2004. Degree holders
were defined as in Figure 2. B, Applications
for K23 grants by degree, 1999-2004. C, First-time applicants for all research
project grant (RPG) awards by degree, 1970-2003. D, Data for MD and MD-PhD
applicants are shown on an expanded scale. First-time applicants indicates
that no other RPG application had been submitted before. E, Total R01 applications
by degree, 1992-2004. F, Applications from MD and MD-PhD applicants are shown
on an expanded scale. Source: National Institutes of Health (NIH).
Customize your JAMA Network experience by selecting one or more topics from the list below.
Ley TJ, Rosenberg LE. The Physician-Scientist Career Pipeline in 2005: Build It, and They Will Come. JAMA. 2005;294(11):1343–1351. doi:10.1001/jama.294.11.1343
Author Affiliations: Section of Stem Cell Biology,
Division of Oncology, Departments of Medicine and Genetics, Siteman Cancer
Center, Washington University School of Medicine, St Louis, Mo (Dr Ley); Department
of Molecular Biology and Woodrow Wilson School of Public and International
Affairs, Princeton University, Princeton, NJ (Dr Rosenberg).
Context Physician-scientists play a unique and critical role in medical research.
Nonetheless, a number of trends followed during the 1980s and 1990s revealed
that this career pathway was in serious jeopardy. Physician-scientists were
declining in number and were getting older. A variety of factors were thought
to contribute to this problem, including increasing indebtedness of medical
school graduates caused by rapidly rising medical school tuition costs.
Objective To evaluate the impact of recently initiated programs from the National
Institutes of Health (NIH) and several not-for-profit institutions designed
to revitalize the physician-scientist career pipeline.
Design We assessed recent trends in the physician-scientist career pipeline
using data obtained from the NIH, the American Medical Association, the Association
of American Medical Colleges, and other sources.
Main Outcome Measures Total numbers of physicians performing research, grant application numbers
and success rates for MDs, MD-PhDs, and PhDs at various stages in their careers,
interest in research among medical students, medical school tuitions and postgraduate
salaries, numbers and composition of applicants for NIH loan repayment programs,
and gender distribution of young physician-scientists.
Results The number of physician-scientists in the United States has been in
a steady state for the past decade, but funded physician-scientists are significantly
older than they were 2 decades ago. However, the study of early career markers
over the past 7 to 10 years has demonstrated increasing interest in research
careers by medical students, steady growth of the MD-PhD pool, and a new burst
of activity in the “late bloomer” pool of MDs (individuals who
choose research careers in medical school or in residency training), fueled
by loan repayment programs that were created by the NIH in 2002. Several recent
trends for more established physician-scientists have also suggested improvement.
Conclusions Although it is too early to assess the impact of these indicators on
the long-term career pathway, the recent growth in activity in the physician-scientist
career pipeline is an encouraging development. Continued funding of these
new programs, coupled with sustained support for physician-scientists committed
to the pathway, will be required to maintain these positive trends.
Physician-scientists are defined as individuals with an MD degree who
perform medical research as their primary professional activity. These investigators
have contributed much to this nation’s preeminent position in medical
science. The majority of physician-scientists have only 1 professional degree,
an MD; a small fraction has a second (eg, PhD, MPH, JD, or MBA). Most physician-scientists
conduct clinical investigation along a broad scientific continuum, from disease-oriented
(seeking mechanisms that cause diseases and the means to diagnose and treat
them) to patient-oriented (using direct patient contact to test hypotheses
concerning etiology, pathophysiology, and management) to population-oriented
(assessing disease incidence and susceptibility with epidemiologic and biostatistical
tools). In addition, many physician-scientists perform basic research (studying
fundamental biological processes).1
The unique perspective that physician-scientists bring to the medical
research workforce is that their scientific questions arise at the bedside
and in the clinic. Regardless of the kind of research they perform, physician-scientists
are imprinted by having cared for sick human beings.
Despite this perspective and the broad range of scientific questions
emanating from it, the pipeline of physician-scientists has a serious problem,
first described more than a generation ago.2 Simply
put, the physician-scientist population in the United States is smaller and
older than it was 25 years ago. These and other disturbing trends have led
some thoughtful observers to conclude that the physician-scientist is an endangered
species, or at least a threatened one.1-16 Once
this alarm was sounded, and the evidence for it confirmed, several National
Institutes of Health (NIH)–sponsored groups, private foundations, and
national organizations called for new initiatives aimed at revitalizing the
physician-scientist career path.
Key players in the United States’ medical research enterprise,
particularly the NIH, have responded impressively to these calls.17,18 In 1998, the NIH established new
career development awards for young physicians being trained to carry out
clinical research (K23), awards for established clinical investigators (K24),
and awards for academic institutions with programs supporting clinical research
training and infrastructure (K30). In 2002, the NIH put in place a series
of competitive loan repayment programs (LRPs) offering at least 2 years of
tax-free debt relief (up to $35 000 per year) for young scientists with
significant debt and a serious commitment to clinically oriented research
The private not-for-profit sector has responded too.16,18,21 Foundations
(led by Burroughs-Wellcome and Doris Duke) created new awards for young and
established physician-scientists. The Howard Hughes Medical Institute appointed
12 new MD investigators engaged in patient-oriented research. Finally, an
increasing number of research-intensive medical schools and hospitals (where
most physician-scientists work) have constructed multifaceted programs aimed
at encouraging medical students to become involved with research before and
after receiving their MD degree and at protecting the research time of young
physician-scientists during their junior faculty appointments.22-24
All of these initiatives, begun between 1998 and 2002, were undertaken
against a very important backdrop: the commitment by Congress and the Administration
to double the NIH budget from approximately $14 billion in 1998 to approximately
$28 billion in 2003. This remarkable growth has increased funding for most
NIH programs, and it raised the tide of confidence for all those engaged in
In this report, we attempt to define the effects that all of these budgetary
and institutional initiatives have had on the physician-scientist career path.
Our data-driven survey relies on information obtained from the NIH, the Association
of American Medical Colleges (AAMC), the American Medical Association (AMA),
and other sources. Our findings offer a more encouraging picture of this professional
cadre than similar surveys performed 5 to 10 years ago.
We obtained the data used in this study from the National Center for
Research Resources, the Division of Information Services of the Office of
Extramural Research, and the Office of Loan Repayment and Scholarship (all
at the NIH), the AMA, and the AAMC. Specified data sets were directly requested
from the described agencies by the authors. No data sources were pooled. Unmodified
data were used in all cases. Some data were extracted by the authors from
the Matriculating and Graduating Student Questionnaires of the AAMC, available
online at http://www.aamc.org/data/msq/allschoolsreports/start.htm and http://www.aamc.org/data/gq/allschoolsreports/start.htm. Data regarding
matriculating MD-PhD students at 42 medical schools with NIH-supported Medical
Scientist Training Programs and 15 schools without such NIH support were provided
by the AAMC and Harvard Medical School. All individual measurements were followed
as a function of time and presented in a variety of formats designed to highlight
selected points deemed relevant by the authors. All data sets were assembled
and analyzed in Excel spreadsheets (Microsoft Inc, Redmond, Wash). All of
the data sets used to create the figures shown are available on request from
the corresponding author (T.J.L.).
The number of physicians engaged in patient care in the United States
has increased steadily for the past 30 years (Figure 1A). In contrast, the number of physicians engaged in research
as their major professional activity declined from peak reported values of
18 535 in 1983 and 23 268 in 1985 to 14 340 in 1995, where
it has since remained virtually constant (14 521 in 2003; Figure 1B). The number of physicians engaged in teaching and research
represents a very small portion of the total physicians in the United States.
Moreover, the percentage of physicians engaged in research has declined steadily
from a peak of 4.6% in 1985 to a level of 1.8% in 2003, both because the pool
of physicians in practice has grown and because the number of physician-scientists
Physician-scientists who successfully compete for NIH research project
grants (RPGs, which include R01, R03, R15, R21, R22, R23, R29, R33, R34, R35,
R36, R37, R55, P01, P42, PN1, PN2, UC1, U01, and U19 grants) are getting older
(Figure 2). In 1986, 306 (24.8%) of
the 1234 RPGs awarded to MDs were to persons older than 50 years; in 2004,
this proportion had increased to 43.7% (741/1696). Approximately 35% (504/1422)
of all awards given to MD-PhDs in 2004 were held by individuals older than
50 years, while nearly 38% (2593/6868) of awards to PhDs went to this age
group. All 3 groups demonstrate the same aging trend, but the effect is most
pronounced for MDs.
Is the aging effect due to an inability of young physician-scientists
to successfully compete for NIH grants? To answer this question, we examined
the success rates for all NIH grant applicants as a function of experience
and degree (Figure 3). When all applicants
are considered, it is clear that MDs, MD-PhDs, and PhDs are similarly successful
at obtaining grants from the NIH (with MD-PhDs having a small advantage in
the past; Figure 3A). When experienced
(ie, previously funded) investigators are considered (Figure 3B), there is again no evidence that physician-scientists
are less competitive. When previously unfunded investigators are evaluated
(Figure 3C), MDs and PhDs have equivalent
success rates, while MD-PhDs are slightly more successful. Previously unfunded
investigators are less successful at obtaining NIH grants, no matter what
degree they hold. In 2003, success rates for all groups were indistinguishable.
Our results suggest that physician-scientists, once in the career pipeline,
are successful at obtaining and maintaining long-term grant support. Why,
then, has there been no growth in the national pool of physician-scientists?
To address one potential explanation, we asked whether medical students are
now less interested in research careers than they were a generation ago.
For several decades, the AAMC has performed surveys of medical students
at matriculation and again at graduation. Using information obtained from
these surveys, we analyzed the number of medical students who were “exclusively”
or “significantly” interested in research as a career activity
at the beginning and end of medical school (Figure
During the decade between 1988 and 1997, research interest declined
among both matriculating and graduating students. Since 1997, there has been
a small but steady increase in interest in research as a career activity among
both matriculating and graduating students. Interest in research has consistently
been 1% to 2% higher in graduates than in matriculants, suggesting that the
medical school experience contributes to an interest in research (the “late
bloomer” effect). Since 1980, a progressively larger fraction of graduating
medical students have indicated that they have an interest in research and
teaching as part of their career activity. The vast majority of students are
interested in clinical topics, not basic research (Figure 4B).
Because the percentage of medical students who are female has nearly
doubled in the past 2 decades, we also wished to examine women’s attitudes
toward research careers. However, none of the questionnaire responses shown
in Figure 4 was classified according
to gender. We therefore examined the gender composition of MD-PhD programs
in the United States, which have exhibited slow but steady growth over the
past decade. Nearly all of this growth has been due to an increase in the
number of women (Figure 5), a trend
matched by an equivalent growth in the number of female applicants (data not
These data do not explain why more young physicians have not chosen
research careers. We therefore turned our attention to another potential disincentive
to research careers, the large debt burdens caused by rapidly rising medical
school tuition costs.
Jolly25 and Morrison26 have
recently summarized the growing problem of escalating medical school debt.
The median educational debt for those graduating from private medical schools
in 2004 was more than $130 000, while those graduating from public schools
had median debts of approximately $100 000.25,26 At
graduation, nearly all physicians obtain additional training that affords
relatively low salaries compared with those of physicians in practice. Physicians
who choose research careers take on many extra years of training and are therefore
more strongly affected by the relatively low wages of residency and fellowship
To evaluate the consequences of debt for young physicians, we compared
the average 4-year tuition costs of public and private medical schools with
the average national postgraduate year 1 (PGY-1) salary (Figure 6). Postgraduate year 1 salaries have increased over the
past 2 decades at a rate that matches inflation (data not shown). However,
4-year tuition costs at private medical schools have increased at a much faster
rate. In 1978, the average cost of 4 years of tuition for private medical
schools ($15 953) was only slightly more than the average PGY-1 salary
($13 965), while the average 4-year tuition bill for public medical schools
was considerably less ($4781). In 2004, the average 4-year tuition bill for
private schools ($115 128) was nearly triple that of the average PGY-1
salary ($40 788); the 4-year tuition of public schools ($47 143)
also now exceeds it. This dramatic shift may represent a disincentive for
highly indebted students to obtain additional training at relatively low wages.
President Clinton signed several initiatives passed by the 106th Congress
that were designed to encourage heavily indebted young professionals to enter
careers in clinical research. Four LRPs (http://www.lrp.nih.gov)
were created by the NIH for clinical research, pediatric research, health
disparities research, and clinical research for individuals from disadvantaged
backgrounds; these were added to an older LRP focused on contraception and
infertility research. Individuals with substantial amounts of debt were encouraged
to apply for LRPs if they were actively receiving training in clinically oriented
research. Individuals could receive up to $35 000 per year in tax-free
debt relief for 2 years and were eligible for a third year of support with
an approved extension. In 2002, applicants also had to be the recipient of
an NIH grant or training grant. This requirement was changed in 2003 (applicants
could be funded by the NIH or any domestic not-for-profit organization), resulting
in a large increase in applications (Figure 7A).
The applicant pool for LRPs has been stable from 2003 to 2005, with
800 to 1000 new applications each year for MDs, 600 to 800 for PhDs, and 100
to 150 for MD-PhDs. Success rates for new applications have been substantial,
ranging from nearly 80% in 2002 to about 39% in 2005. A total of 1791 LRPs
were awarded to MD researchers in the first 4 years of the program, with 1356
awarded to PhDs and 303 to MD-PhDs. The number of LRPs awarded annually far
exceeds the number of 250 per year that was originally suggested by the NIH
leadership in 2002.19 As expected, indebtedness
for MD recipients of LRPs was substantially greater than for that of either
PhDs or MD-PhDs. For example, in the clinical and pediatrics programs (which
fund the largest number of applicants), the average debts for successful MD
applicants were $126 000 (clinical) and $139 000 (pediatric) in
2004. In contrast, the average debts for successful PhD applicants were $56 000
(clinical) and $64 000 (pediatric) and for funded MD-PhD applicants,
$80 000 (clinical) and $69 000 (pediatric). Women have constituted
46% to 48% of the first-time MD applicants each year and 24% to 29% of the
MD-PhD group (Figure 7B). Men and women
have had approximately equivalent success in receiving awards among all 3
degree-holding groups (data not shown).
To assess the numbers of physician-scientists entering the career pathway
via the NIH granting mechanism, we evaluated the growth of applications for
early career awards primarily targeted for the support of young physician-scientists.
The K08 awards are mentored early career awards designed to support individuals
performing clinically oriented investigation that can be either basic or translational
in nature. Since the inception of the K08 program in 1972, the NIH has increased
its total funding to nearly $38 million in 2004 (Figure 8A). As funding has increased, the applicant pool has likewise
increased but the number of funded awards has remained virtually constant
over the past decade (Figure 8B). For
this reason, the success rate for K08 applications has decreased from the
60% level in the mid 1990s to its current level of 40% (Figure 8C). The growth of the K08 applicant pool is further examined
in Figure 9A. Most of the growth in
applications over the past decade has come from MD-PhDs, with more modest
growth from MD applicants. Both have been increasing at the same rate over
the past 4 years.
The K23 awards, initiated in 1999, are mentored early career awards
for individuals doing patient-oriented research. This program has expanded
rapidly over the past several years, with most applications coming from MDs
(Figure 9B). Few MD-PhDs have sought
this type of career development support.
We also examined the number of “first-time” applicants for
RPG awards as an indicator of the size of the pool of physician-scientists
entering academic positions (Figure 9C
and Figure 9D). Although there has been
an overall increase in the number of first-time applicants in recent years
(perhaps engendered by the concurrent doubling of the NIH budget), this growth
has been largely caused by an increased number of applications from PhDs (Figure 9C). First-time MD applicants, whose numbers
hovered at 750 to 800 between 1995 and 1999, have slowly increased recently,
reaching a total of 995 in 2003 (Figure 9D).
First-time RPG applicants with MD-PhD degrees have steadily increased, from
133 in 1970 to 600 in 2003. The growth in total R01 applications (the largest
component of RPGs) is shown in Figure 9E
and Figure 9F; most of the recent growth
has come from PhD candidates (Figure 9E).
Even though MD-PhDs comprise only a small percentage of medical school graduates,
the number of R01 applications from MD-PhDs in 2004 (3859) is now approaching
that of MDs (4409; Figure 9F).
The data we have collected offer a more encouraging picture of the physician-scientist
career path than any presented over the past 5 to 10 years. While it is much
too early to declare that the problem of rescuing the physician-scientist
population has been solved, many indicators are now going in the right direction.
Of the 12 indicators we have examined, 9 offer encouraging trends, and these
extend from the earliest cohort (medical students) to the most mature (established
NIH investigators). Some of these trends warrant special emphasis.
If there is to be a secure future for physician-scientists, it must
begin with medical students. We are heartened that a progressively larger
fraction of both matriculating and graduating medical students have recently
indicated serious interest in research careers. This positive trend reverses
one noted since the late 1980s.11,14 Since
interest is higher in the graduating cohort, the data suggest that the medical
school experience actually enhances research interest. Furthermore, during
the past 20 years, a growing fraction of medical students have indicated that
they want teaching and research to be part of their career activities. These
trends are important, since medical students represent the critical pool from
which the next generation of physician-scientists (particularly the late bloomers)
must be drawn.
Three of the sampled indices (LRP, K08, and K23 applications) survey
physician-scientists during the first several years of their research training
experience. Each of these populations is characterized by positive trends.
For example, examination of the first 4 years of the LRP program shows that
there is a large, sustained pool of MDs and MD-PhDs whose indebtedness matters
enough to apply (and, almost certainly, to affect career choice). If a reasonable
fraction of the nearly 2100 MDs and MD-PhDs who have been awarded LRPs join
the ranks of committed physician-scientists, this will change the demographics
of the career ladder in a significant way. Likewise, the number of applications
for K08 awards has increased during the past 5 years for MDs and MD-PhDs alike.
So, too, have applications submitted by MDs for the newer K23 award. Sustaining
these positive trends is a major challenge that we will further discuss herein.
Five of the indicators we examined evaluate trends for this population.
The picture is mixed, but this is expected because most of the recent initiatives
taken by the NIH and medical schools have been directed toward young scientists
and because there has not been sufficient time for these efforts to have a
discernible effect on the larger population of established scientists. Thus,
we are not surprised that the overall national population of physician-scientists
is not currently increasing, nor that the fraction of grants awarded to NIH-funded
investigators older than 50 years has increased over the past 2 decades (for
MDs, MD-PhDs, and PhDs alike). However, 3 other indices in this group are
encouraging. Since 1998, more MDs and MD-PhDs are applying for their first
NIH research project grants than in the recent past, and the same trend is
noted for R01 applications. Importantly, MDs also remain as competitive as
PhDs for NIH project grants, whereas MD-PhDs have performed slightly better
than either of them. Thus, there is reason to believe that an increase in
the pool of trained physician-scientists applying for NIH grants will be translated
into a larger number who are funded.
Seven indicators offer information about this important population.
First, the national population of MD-PhD students is remarkably small at fewer
than 600 total matriculants in 2005, or approximately 4% of the total medical
student population. Over the years, however, MD-PhD graduates have constituted
a growing fraction of funded physician-scientists, and that trend continues.
They are overrepresented in the pool of K08 applicants, first-time RPG applicants,
and R01 applications, clearly indicating the success of this program for producing
successful physician-scientists with sustained academic careers.
Because the MD-PhD pool is growing slowly, and because MD-PhDs tend
to perform basic and disease-oriented research,14 late
bloomers who become attracted to research during and after medical school
will continue to be an essential source of future physician-scientists (especially
for patient-oriented research). Several pieces of evidence support the view
that this pool can be expanded. The increasing interest of medical students
in research is one example. The impressive and unexpectedly large number of
applicants for LRPs is another. The growing number of applicants for K08s
and K23s is a third. A combined approach demonstrating that this career path
is plausible and feasible, coupled with sustained efforts to remove financial
and institutional obstacles, is warranted in light of these encouraging trends.17,19
Because half of incoming medical students are now women and because
women have lagged behind men in their preference for research careers,27,28 we are particularly heartened by
3 indicators in our survey. The first shows that the fraction of MD-PhD students
who are women has increased markedly during the past 7 years (from 27% of
the total in 1997 to 41% in 2005). The second and third evaluate the gender
breakdown of the LRPs: in each year for which we have data (2002-2005), women
constituted 46% to 48% of the new MD applicant pool for LRPs, and their funding
success was not different from that of men.
We are encouraged by the results in this report but also are mindful
of the many uncertainties they raise. First, given that the “doubling
era” for the NIH budget is over, that further growth in that budget
will be very modest, and that the initiatives we have described all cost money,
how can the positive trends be continued? The answer is simply that the leadership
of the NIH and other constituencies in the US medical research enterprise
must accord these initiatives a high enough priority to be sustained (or even
expanded) in the years ahead. For example, attracting large numbers of MDs
to research via LRPs must be followed by sufficient funding of K08 and K23
awards. Continued strong funding of RPG applications will also be required
to sustain careers beyond the entry phase.
Second, when can we expect to see a younger physician-scientist workforce?
If the recipients of LRPs and early career awards are successful at the next
stage of their careers, the average age of physician-scientists should begin
to decrease during the next decade (that decrease in age may not be dramatic,
however, since research careers now begin later in life than a generation
ago because of lengthened training requirements).
Third, preparing this report has once again reminded us of the pressing
need for a national database that is capable of tracking the indices we have
examined and others like them. Such a database is essential to monitor trends,
discern issues, and make corrections as needed. We hope that the Institute
of Medicine, AAMC, and NIH will work together to address this pressing infrastructure
New programs recently initiated by the NIH and private foundations are
beginning to have a positive impact on the decisions of young physicians to
pursue research careers. To maintain this trend, strong funding commitments
will be required beyond the entry level. If these commitments are sustained,
we are cautiously optimistic that they will result in an increase in the population
of physician-scientists in the United States in the near future.
Corresponding Author: Timothy J. Ley, MD,
Division of Oncology, Section of Stem Cell Biology, Washington University
School of Medicine, Campus Box 8007, 660 S Euclid Ave, St Louis, MO 63110
Author Contributions: Drs Ley and Rosenberg
had full access to all of the data in the study and take responsibility for
the integrity of the data and the accuracy of the data analysis.
Study concept and design: Ley, Rosenberg.
Acquisition of data: Ley, Rosenberg.
Analysis and interpretation of data: Ley, Rosenberg.
Drafting of the manuscript: Ley, Rosenberg.
Critical revision of the manuscript for important
intellectual content: Ley, Rosenberg.
Statistical analysis: Ley.
Obtained funding: Ley.
Administrative, technical, or material support:
Study supervision: Ley, Rosenberg.
Financial Disclosures: None reported.
Funding/Support: The Alan and Edith Wolff Chair
provided support for Dr Ley.
Role of the Sponsor: The funding source had
no role in the design and conduct of the study, in the collection, analysis,
and interpretation of the data, or in the preparation, review, or approval
of the manuscript.
Acknowledgment: We are grateful to Alfred Johnson,
Office of Loan Repayment and Scholarship, NIH, Robert Moore, and the staff
of the Division of Information Services Office of Extramural Research, NIH,
Derek Smart at the AMA, and Le’Etta Robinson and Gwen Garrison at the
AAMC for fulfilling our many requests for data in a timely and professional
manner. We also thank Linda Burnley at Harvard Medical School for providing
data regarding the MD-PhD matriculants. We thank Denise Kampwerth and Jason
Books, Washington University Medical School, for help with data management
and Marcy Hartstein and Andrea Myles at Washington University’s MedPic
for creating the figures. Nancy Reidelberger, Washington University Medical
School, and Patricia Fox, Princeton University, provided expert assistance
with manuscript preparation.