Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 27
5
Representation of Underrepresented Minorities
NIH TRAINING GRANTS1
Associating training grants with the universities to which a program belongs, the panel
investigated two questions about the relationship of training grant awards to underrepresented
minority (URM) students and to international students.
Do institutions with heavy dependence on training grants recruit more students who are from
underrepresented minority groups (URMs) than schools with less dependence?
To explore this question, the number and percentage of URM students were plotted against
the number of training grants for each institution. Data showing the numbers of URM’s as well
as the percentage by institution are given in Figures 5-1a and 5-1b. Numbers were used in
Figure 5-1a to test the hypothesis that the more training grants an institution has, the more URMs
it will recruit. Figure 5-1b, using the percentage of URMs, shows that, even in institutions with a
large number of training grants, the representation of URMs is about average, and is similar to
institutions with fewer grants.
It is true that the programs with more URM students also are the larger departments and the
ones with higher research productivity. Hence, while a higher number of NIH training grants go
to programs with a larger number of minority Ph.D. students, it is not necessarily true that the
proportion of support going to minorities is greater because of the training grants. Program
specific data would be important for an analysis that addresses this more challenging question.
1
A note on the data: Using NIH data, we were unable to associate training grant funding with particular programs.
We were, however, able to tie them to particular institutions, and this is the approach we take in the analysis that
follows. MARC training grants were not included.
27
OCR for page 28
28 RESEARCH-DOCTORATE PROGRAMS IN THE BIOMEDICAL SCIENCES
FIGURE 5-1a Comparison of the Number of Training Grant Awards and the Number of
Underrepresented Minorities by Institution. The correlation between training grants and number of URM
students is 0.748.
OCR for page 29
REPRESENTATION OF UNDERREPRESENTED MINORITIES 29
FIGURE 5-1b Comparison of the Number of Training Grant Awards and the Percentage of
Underrepresented Minorities by Institution. The correlation between training grants and the percentage of
URM students is 0.000.
The above notwithstanding, there are some institutions that stand out as having a high
percentage of URM students, regardless of the number of training grants (see Table 5-1).
OCR for page 30
30 RESEARCH-DOCTORATE PROGRAMS IN THE BIOMEDICAL SCIENCES
TABLE 5-1 Institutions with programs having 20 percent or more URM students and the number of
their training grant awards
Average Percent Average of Number of
of URM Students Training Grant Awards
Institution Name
Howard University 95% 3
New Mexico State University Main Campus 48% 2
City University of New York Grad. Center 38% 1
University of North Texas Health Science Center 37% 2
Loma Linda University 35% 0
University of Georgia 32% 3
University of New Mexico Main Campus 31% 6
University of Southern Mississippi 30% 0
University of Miami 27% 3
Auburn University 26% 0
Florida International University 26% 0
University of North Carolina at Greensboro 25% 0
University of South Carolina Columbia 24% 0
University of Louisville 23% 5
Oklahoma State University Main Campus 23% 1
University of California-Santa Cruz 21% 5
University of Maryland Baltimore County 21% 2
More analysis is needed to identify the characteristics of these institutions that make them
particularly successful in recruiting URM doctoral students.
Do institutions with heavy dependence on training grants enroll fewer international students?
Here we looked at the percentage of international students in a program related to the number
of training grants the institution holds. As shown in Figure 5-2, institutions with greater than 15
training grant awards had an average of about 25 percent international students in their
biomedical sciences programs, compared to about 35 percent at institutions with smaller
numbers of grants. Since international students cannot be supported on NIH training grants, this
difference is not surprising.
OCR for page 31
REPRESENTATION OF UNDERREPRESENTED MINORITIES 31
FIGURE 5-2 Percent of International Students at an Institution Grouped by Number of Training
Grants (All Institutions) The correlation between training grants and the percentage of international
students is -0.240
A STATISTICAL APPROACH
Another approach to issues relating to underrepresented minorities is to develop a model of
enrollment by URM’s that relates enrollment to other program characteristics, in order to better
understand how to expand their enrollment and graduation from Ph.D. programs. Toward that
end, the biomedical sciences data of the Assessment can identify factors associated with higher
URM enrollment among the participating programs. The panel addressed three questions in turn:
• How many URM graduates are expected per year across all programs?
• What factors predict higher URM enrollment in a PhD program?
OCR for page 32
32 RESEARCH-DOCTORATE PROGRAMS IN THE BIOMEDICAL SCIENCES
• Having controlled for these factors, to what extent does URM enrollment cluster
within universities, and which universities exceed URM enrollment expectations?
URM Ph.D. Students and Graduates
There are close to 40,900 Ph.D. students in the 982 biomedical sciences programs in the
Assessment. Of these, approximately 4,700 (11.5 percent) are from underrepresented minority
groups (URMs). Figure 5-3 shows the distribution of the percentage of URM Ph.D. students
across the programs (0 = no URM students; 100% = all are URMs). The median percent of
URMS is 10 percent; the middle half of programs have between 4 and 16 percent of URM Ph.D.
enrollments, which corresponds to 1 to 7 URM students.
FIGURE 5-3 Histogram Describing the Percentage of URM Ph.D. Students for 981 Bioscience Programs2
Figure 5-4 shows the distribution of the expected number of URM graduates per year.
This measure for a program is estimated by multiplying the share of enrolled URM students by
the average number of graduates over the previous 3 years. Seventeen percent of programs are
expected to graduate more than one URM student per year; three percent of programs are
2
One of the 982 programs did not have data for URMs.
OCR for page 33
REPRESENTATION OF UNDERREPRESENTED MINORITIES 33
expected to graduate two or more. Of the approximately 4,700 new Ph.D.’s per year over the 982
departments, roughly 550 were URM graduates.
FIGURE 5-4 Histogram Describing the Expected Number of URM PhD Graduates per Year for 982 Bioscience
Programs
Factors that Predict URM Enrollments
To identify key factors that predict the number of URM graduate students in a program, the
panel used Poisson log-linear regression to predict the expected rate of enrolled URM students
(number URM per total enrolled students) as a function of the following factors:
• number of URM faculty;
research productivity as measured by the 5th percentile of the NRC “research
•
productivity” ranking3; and
• biomedical science field.
3
Other variables (e.g., completion rate or percent of first year students with full financial support) could be used in
this analysis.
OCR for page 34
34 RESEARCH-DOCTORATE PROGRAMS IN THE BIOMEDICAL SCIENCES
The model also includes a random effect for each university to account for the correlation
among URM enrollments among programs from the same university (see below). The regression
coefficients are estimates of log relative rates of URM enrollment per unit change of the
predictor, other variables held fixed. For example, the exponential of the coefficient for the URM
faculty fraction is the factor that multiplies the expected URM student enrollments if the fraction
of URM faculty increases from 0 to 100 percent. A factor of 1.0 = exp(0) means that the
percentage of URM faculty has no effect on the fraction of URM PhD students; a factor of 3
means that an increase in URM faculty members from 10 to 20% is associated with an increase
in the fraction of URM enrolled students from 10 to 40%. Table 5-2 shows a subset of the
results of this log-linear regression.
TABLE 5-2 Predictor, Estimated Relative Rate (RR) and t-Statistic for Null
Predictor Relative Rate t-statistic
Biochemistry, Biophysics, and Structural Biology+ 1 -------
Biomedical Engineering and Bioengineering 1.17 2.26
Cell and Developmental Biology 1.16 2.44
Genetics and Genomics 1.09 1.09
Immunology and Infectious Diseases 1.32 3.56
Integrated Biological and Biomedical Sciences 0.97 -0.42
Microbiology 1.35 4.15
Neuroscience and Neurobiology 1.25 3.45
Nutrition 1.35 2.91
Pharmacology, Toxicology, and Environmental Health 1.48 6.08
Physiology 1.28 2.71
URM Faculty Fraction 2.96 3.160
Research Productivity 1.0015 1.73
NOTE: RR=1 from log-linear regression of the number of URM PhD students on the indicators of field;
biochemistry, biophysics, and structural biology is the reference program with RR assigned to be 1.0,
fraction of URM (0-1), and for the 5th percentile of the research productivity (0-100).
OCR for page 35
REPRESENTATION OF UNDERREPRESENTED MINORITIES 35
The relative rate estimates for biochemistry, biophysics, and structural biology and for
integrated biological and biomedical sciences are the smallest, indicating that among the
observed data, they are the least well-subscribed biomedical science departments by URM
students, all else being equal. Pharmacology, toxicology, and environmental health,
microbiology, immunology and infectious disease, and nutrition have the largest estimates,
which range from 35 to 48 percent higher rates of enrollment than in biochemistry, biophysics,
and structural biology.
Research productivity of the program faculty is not a strong predictor of URM Ph.D.
student enrollment, once the number of PhD students is taken into account. However, as would
be expected, the fraction of URM faculty is a very strong predictor. For a 10 percentage point
increase, say from 5 to 15 percent of URM faculty, the fraction of URM Ph.D. enrollments is
expected to increase by 26.1 percentage points, nearly a 3-to-1 ratio. This is by far the most
important predictor among those considered.
Clustering of URM Students
Many universities have a large number of Ph.D. programs (ranging from 1 to 18) in the
Assessment. Therefore, it is possible to ask whether there are unmeasured characteristics of each
university that attract URM Ph.D. students beyond the predictors considered above. Because
such factors are common to all programs from a university, their influence can be detected as
correlation or “clustering” among the rates of URM enrollments for programs from the same
university.
A simple extension of the log-linear model above can be used to estimate the degree of
clustering by adding a random “university effect” that is common to all the programs within that
institution. We have added a random intercept to the Poisson regression described above. With
this model, we have estimated the multiplicative factor that indicates how each university’s
URM enrollment is increased or decreased across all of its programs using empirical Bayes
estimation as implemented in the software package Stata (Rabe-Heckesh, Skronda, and Picles
(2002).4 Table 5-3 lists the estimated relative rates for the 10 universities with the highest values.
4
Rabe-Heckesh, S., A. Skronda, and A. Picles. 2002. Reliable estimation of generalized mixed models using
adaptive quadrature. The Stata Journal, Vol. 2, (1), 1-21.
OCR for page 36
36 RESEARCH-DOCTORATE PROGRAMS IN THE BIOMEDICAL SCIENCES
TABLE 5-3 Listing of the Universities with Highest “University Relative Rates”
Institution Relative Rate
Howard University 3.98
City University of New York 3.52
New Mexico State University 3.44
University of New Mexico Main 3.29
University of North Texas HSC 3.25
Loma Linda University 2.36
University of Texas HSC 2.36
University of Maryland Baltimore 2.12
University of Georgia 2.10
University of Miami 2.09
____________________________________________________________________________________
NOTE: These rates indicate the attractiveness of the university’s programs beyond what is predicted by
the field, percent of URM faculty, and research productivity.
The degree of clustering of URM graduate students is substantial, even after controlling
for the clustered URM faculty. The standard deviation of the university effect is estimated to be
0.50 (95 percent confidence interval 0.43 to 0.59). A standard deviation of 0.5 for a Gaussian
distribution means that roughly 1 of 3 universities would have relative rates below 0.6 or above
1.6, a demonstration of important variation among institutions in their ability to attract URM
PhD students, even after controlling for variation among them in their fractions of URM faculty,
research productivity, and field.
